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Bibliography on: Biofilm

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ESP: PubMed Auto Bibliography 04 Oct 2025 at 01:39 Created: 

Biofilm

Wikipedia: Biofilm A biofilm is any group of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances (EPS). The EPS components are produced by the cells within the biofilm and are typically a polymeric conglomeration of extracellular DNA, proteins, and polysaccharides. Because they have three-dimensional structure and represent a community lifestyle for microorganisms, biofilms are frequently described metaphorically as cities for microbes. Biofilms may form on living or non-living surfaces and can be prevalent in natural, industrial and hospital settings. The microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism, which, by contrast, are single-cells that may float or swim in a liquid medium. Biofilms can be present on the teeth of most animals as dental plaque, where they may cause tooth decay and gum disease. Microbes form a biofilm in response to many factors, which may include cellular recognition of specific or non-specific attachment sites on a surface, nutritional cues, or in some cases, by exposure of planktonic cells to sub-inhibitory concentrations of antibiotics. When a cell switches to the biofilm mode of growth, it undergoes a phenotypic shift in behavior in which large suites of genes are differentially regulated.

Created with PubMed® Query: ( biofilm[title] NOT 28392838[PMID] NOT 31293528[PMID] NOT 29372251[PMID] ) NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

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RevDate: 2025-10-03

Gambardella C, Basili M, Castelli F, et al (2025)

Early biofilm colonization on traditional and biodegradable plastics in the Baltic Sea using a mesocosm approach.

Marine environmental research, 212:107592 pii:S0141-1136(25)00649-X [Epub ahead of print].

Bioplastics are promising alternatives to conventional plastics, but their potential entry into marine ecosystems highlights the need for a better understanding of their interactions with microbial communities, including their role in the plastisphere. Here, we characterized the early biofilm formation on traditional plastics and bioplastics using a mesocosm approach. We tested the hypothesis that distinct bacterial communities selectively colonize traditional and biodegradable plastics in the marine environment. Specifically, fragments of the petroleum-based plastic polypropylene (PP) and the bioplastics Poly(3-hydroxybutyrate)- hydroxyvalerate (PHBv) and polylactic acid (PLA) were submerged in Baltic Sea mesocosms for three weeks. Biofilm colonization, prokaryotic abundance, and community composition were assessed through scanning electronic microscopy analysis, epifluorescence microscopy and 16S rRNA gene metabarcoding, respectively. Biofilm development increased over time on both traditional and bioplastics, with photosynthetic organisms appearing after 3 weeks. However, prokaryotic abundance decreased over time except on PLA surfaces. Prokaryotic communities' composition differed among biofilms formed on the different polymers. The microbial community associated with conventional plastic PP was more similar to that of the seawater in the control treatment, while biofilms on PLA and PHBv shared a higher degree of similarity with each other. These findings suggest that microbial communities selectively colonize different plastic types, with bioplastics supporting distinct and specific bacterial biofilm assemblages over three-week exposure. The great diversity observed in bioplastics, particularly PLA, suggests they may support more complex and potentially active plastisphere communities after only three weeks of exposure to the Baltic Sea.

RevDate: 2025-10-03
CmpDate: 2025-10-03

Singh J, Agrawal RK, Bankoti K, et al (2025)

Antibacterial, anti-biofilm and anti-virulence activity of biosynthesized silver nanoparticles against drug-resistant Staphylococcus aureus.

Veterinary research communications, 49(6):345.

Antibiotic resistance in bacteria has become a major concern for the effective treatment of infections; therefore, alternatives to antibiotics are being extensively researched to combat drug-resistant microbes. In this study, silver nanoparticles (AgNPs) were biosynthesized using aqueous extracts of papaya leaves (Carica papaya), cannabis leaves (Cannabis sativa), and cardamom (Elettaria cardamomum) and characterized by field-emission scanning electron microscopy (FE-SEM) and UV-visible spectrophotometry. Biosynthesized AgNPs were evaluated for their antibacterial, anti-biofilm, and anti-virulence potential by phenotypic and genotypic methods. AgNPs biosynthesized by all three extracts had spherical morphology and sizes in the nanoscale, average diameter ranging from 46.05 to 94.12 nm. Antibacterial susceptibility testing of S. aureus field isolates under study revealed 48% (24/50) and 38% (19/50) to be resistant to methicillin and amoxycillin-clavulanic acid, respectively. Antibacterial activity of biosynthesized AgNPs against S. aureus strains was determined by the well diffusion method. AgNPs were found to be effective on 90.90% (50/55) S. aureus strains with a zone of inhibition varying from 10 to 21 mm. The AgNPs were also found to be effective on other important bacterial pathogens (viz. Bacillus cereus ATCC 10876, Pseudomonas aeruginosa ATCC 27853, Salmonella Enteritidis ATCC 13070, Escherichia coli ATCC 43888, and Listeria monocytogenes MTCC 657) screened in the study with a ZOI of 15-18 mm. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNPs against S. aureus ranged between 0.015625-0.125 mg/mL and 0.015625-0.25 mg/mL, respectively. In the time kill assay, AgNPs were able to kill S. aureus rapidly within 0.5-1.0 h. In the haemolytic assay, 4-9% haemolysis was observed at concentrations ranging from 0.015625 to 0.25 mg/mL of AgNPs. Biofilm-forming ability of all strains of S. aureus (n = 55) determined by crystal violet assay revealed that 87.27% (48/55) were biofilm formers, while 12.73% (7/55) were non-biofilm formers. Out of 48 biofilm-forming strains, 81.25% (39/48) were strong biofilm producers, 10.41% (5/48) were moderate biofilm producers, and 8.33% (4/48) were weak biofilm producers. Anti-biofilm effect of AgNPs was found at sub-MIC (0.03125 mg/mL), phenotypically. Exopolysaccharide production was found to be reduced by 53.38% indicating the anti-virulence potential of AgNPs at sub-MIC. Relative expression analysis revealed that AgNPs downregulated the expression of biofilm-related genes, namely icaC, icaD, and spa, by 14.2, 10.6, and 8.7-fold, respectively, compared to the control at 3 h of incubation. Other biofilm-related and virulence genes, including icaA, icaB, icaR, agr, ebps, fnb-B, sar-A, and katA, were also found to be downregulated by 7.4, 7.5, 6.2, 5, 4.2, 7.3, 4, and 3.6-fold, respectively, at 3 h. All the target genes were also found to be downregulated at 24 h post-treatment with AgNPs, except icaD, icaR, and agr, which were slightly upregulated. In the present study, AgNPs were successfully biosynthesized and found to possess broad-spectrum antibacterial activity, reduce biofilm formation, and EPS production. Biosynthesized AgNPs has potential to be utilized as antibacterial, anti-biofilm, and anti-virulence agents against S. aureus, as alternative to conventional antibacterial agents.

RevDate: 2025-10-03
CmpDate: 2025-10-03

Sahai S, NK Das (2025)

Antibiotic resistance and biofilm formation in Klebsiella pneumoniae: A global health threat.

Journal of family medicine and primary care, 14(8):3610-3611.

RevDate: 2025-10-03
CmpDate: 2025-10-03

You W, Xiao F, Cai Z, et al (2025)

Biofilm-disrupting heterojunction microneedles: dual ROS amplification and glucose deprivation for accelerated diabetic wound healing.

Theranostics, 15(18):9757-9774.

Rationale: Diabetic wound healing process is critically hindered by bacterial infection, bacterial biofilm formation, and persistent hyperglycemia. Biomolecular microneedles represent a promising alternative to conventional therapies such as antibiotics and antibiotic-loaded wound dressings, owing to the advantages like reduced risk of drug resistance and enhanced long-term efficacy. However, the microneedles that fulfill the clinical needs of diabetic wounds have rarely been reported. Methods: A glucose oxidase (GOx)-laden Ti3C2/In2O3 (INTG) heterojunction was engineered as a nano-micro platform for reactive oxygen species (ROS) amplification and glucose deprivation, and subsequently immobilized onto the gelatin methacryloyl (GelMA) microneedle tips to obtain double-layer microneedles (GITG microneedles). Their physiochemical properties and biomedical applications were comprehensively investigated. Results: For INTG heterojunction, the formation of Schottky structure significantly improved the oxygen absorption capacity, facilitated the generation and migration of photogenerated electron-hole pairs, thereby promoting the ROS generation. Besides, under near-infrared (NIR) irradiation, GITG microneedles effectively inhibited bacterial proliferation and survival by generating ROS, thereby preventing the formation of bacterial biofilm. Additionally, GITG microneedles accelerated wound closure and facilitated skin tissue regeneration in a rat model through multiple mechanisms. Conclusion: This study developed an advanced microneedle platform enabling on-demand multimodal treatment, demonstrating significant potential for clinical diabetic wound management.

RevDate: 2025-10-03
CmpDate: 2025-10-03

Chen Y, Lin S, Huang X, et al (2025)

From biofilm control to biomimetic remineralization: Hydrogels in prevention and treatment of dental caries.

Frontiers in cellular and infection microbiology, 15:1663563.

Dental caries, a prevalent chronic bacterial disease globally, poses a significant threat to public health due to its complex pathogenesis involving demineralization and microbial dysbiosis. Hydrogels, with their unique three-dimensional network structures and diverse properties, have shown great potential in prevention and treatment of dental caries. This article systematically reviews recent advances in anti-caries hydrogel development. It first introduces the basis of anti-caries hydrogels, covering the applications of natural and semi-synthetic polymers as hydrogel matrices. Then, it elaborates on the mechanisms and research status of different types of anti-caries hydrogels, including probiotic formulations, antibacterial hydrogels, remineralization-inducing hydrogels, and saliva-related caries-reducing hydrogels. Finally, it summarizes the current research achievements and limitations and looks ahead to future research directions.

RevDate: 2025-10-03
CmpDate: 2025-10-03

Bennett AN, Maziarz JF, Laipply B, et al (2025)

Mechanisms of antibiofilm compounds JG-1 and M4 across multiple species: alterations of protein interactions essential to biofilm formation.

Frontiers in cellular and infection microbiology, 15:1631575.

The majority of human bacterial pathogens have the ability to form biofilms in vivo on body tissues and implantable medical devices. Biofilm-mediated chronic bacterial infections are difficult to treat due to their recalcitrance to antimicrobials and immune effectors, often requiring invasive surgical intervention to clear the infection. The difficulty in effectively executing these treatment strategies underscores the need for therapeutic agents that specifically target the biofilm state. To this end, we previously identified two small molecules, JG-1 and M4, that in vitro effectively inhibit and disperse biofilms of Salmonella Typhimurium and members of the ESKAPE pathogen group, including Enterobacter cloacae, Pseudomonas aeruginosa, and Acinetobacter baumannii. In addition to its antibiofilm effects, M4 has a bactericidal effect on Staphylococcus aureus and Enterococcus faecium. While these compounds have promising utility as antimicrobial agents, their mechanism of action remains unknown. By employing multiple techniques including RNAseq, thermal proteome profiling, and site directed mutagenesis, we identified multiple proteins essential to biofilm formation and evaluated their role in the presence of JG-1 and M4 in mutant and wildtype backgrounds. We report that the JG-1 and M4 actions are influenced by proteins important to biofilm maintenance, including OmpA, OmpC, and TrxA. Compound-bacteria interactions cause transcriptional changes that result in biofilm dispersal, and modulation of other virulence mechanisms, including invasion and motility. Additionally, we report that M4 interacts with S. aureus CodY, which promotes cell death, while the specific targets in S. Typhimurium and E. cloacae remain elusive. Collectively, this study presents an empirical investigation into JG-1 and M4's mechanism of action in S. Typhimurium, E. cloacae, and S. aureus, and how the antibiofilm compounds disrupt microbial community dynamics, ultimately driving biofilm dispersal or cell death.

RevDate: 2025-10-03
CmpDate: 2025-10-03

Withorn JM, Ramcharan K, Alfano NE, et al (2025)

Pseudomonas aeruginosa uses kinases NahK and RetS to control the motile-biofilm switch.

bioRxiv : the preprint server for biology pii:2025.09.24.678285.

The multidrug-resistant bacterium Pseudomonas aeruginosa (Pa) poses a significant threat to public health. This Gram-negative bacterium establishes pathogenicity through formation of multicellular communities, known as biofilms, that result in significant resistance to antibiotics and host immune systems. In Pa , the motile-to-biofilm transition is regulated through an interconnected signaling network known as the Gac Multikinase Network (Gac-MKN). This network comprises two regulatory branches: the HptB signaling network and GacS/A signaling network. In the Gac-MKN, several histidine kinases converge to regulate the activity of the post-transcriptional regulator protein, RsmA. Although previous studies have assessed the role of individual kinases in this network, the role of each Gac-MKN kinase in regulating RsmA activity has not been quantitatively characterized and compared in side-by-side experiments in the same reference strain, which is presented here. In this study, we show that kinases NahK and RetS are the predominant regulators of the Gac-MKN. Through controlled testing of RsmA-dependent phenotypes, we demonstrate loss of nahK or retS leads to complete inactivation of RsmA, triggering biofilm formation. Our results support previous findings that RetS regulates RsmA through the GacS/A network but present the new finding that NahK is the central kinase involved in HptB phosphorylation; previous studies have attributed HptB phosphorylation to PA1611 and SagS. Our findings demonstrate that NahK signaling controls RsmA activity to rapidly transition between the motile and biofilm states. We anticipate the results of this study will facilitate the use of targeting the Gac-MKN to trigger biofilm dispersal for improved antibiotic treatment.

RevDate: 2025-10-03

García C, Saralegui L, Morales B, et al (2025)

Identification of ShgH as a dual histidine/glutamine transporter component essential for Streptococcus suis virulence and biofilm modulation.

Microbiological research, 302:128354 pii:S0944-5013(25)00313-1 [Epub ahead of print].

Streptococcus suis is a zoonotic pathogen that affects pigs and humans. In this study, we characterised ShgH, a predicted substrate-binding component of an ABC transporter. Immunoassays confirmed that ShgH is expressed, secreted and surface-exposed in S. suis, in agreement with its proposed transporter function. Isothermal titration calorimetry demonstrated that ShgH binds glutamine and histidine, with a higher affinity for histidine. Deletion of the shgH gene significantly impaired uptake of both radiolabelled amino acids confirming its role as part of a transporter. Functional analysis revealed that shgH deletion results in a marked reduction in virulence in a murine infection model, while host colonization remained unaffected. ShgH contributes to infection by facilitating evasion of phagocytosis and resistance to oxidative stress through impaired nutrient acquisition and reduced capsule production. In addition, ShgH regulates biofilm formation and architecture. Notably, ShgH is highly conserved among pathogenic streptococci, suggesting a broader functional relevance. Altogether, our findings identify ShgH as a dual glutamine/histidine- binding protein essential for nutrient uptake and virulence in S. suis, and a promising target for future therapeutic interventions.

RevDate: 2025-10-02
CmpDate: 2025-10-03

Sato Y, Hatayama N, Suzuki Y, et al (2025)

Urinary tract infection due to Staphylococcus schleiferi biofilm formation in the subcutaneous ureteral bypass system in a cat.

BMC veterinary research, 21(1):566.

BACKGROUND: Staphylococcus schleiferi is mainly isolated from dogs and occasionally infects cats. We recently encountered a case of a biofilm-related urinary tract infection (UTI) caused by S. schleiferi in a cat with a subcutaneous ureteral bypass (SUB) system. This report presents a case of biofilm formation by S. schleiferi in the SUB system and discusses the causes of UTIs.

CASE PRESENTATION: A 9-year-old female cat had been using the SUB system since 4 years-of-age. The cat had no significant clinical history or UTIs for 4 years after the first implantation of the SUB system. The SUB system was flushed once per month. When the cat was 8 years-of-age, the subcutaneous port of the SUB system was contaminated with Staphylococcus pseudintermedius and replaced with a new one. Subsequently, the SUB system had no particular problem for 8 months. The SUB system was flushed once every 2 months. However, the cat occasionally developed gross haematuria. Additionally, S. schleiferi was detected in urine. Although doxycycline was administered to the cat, 6 weeks later, the cat had cutaneous wounds with abscesses caused by excessive grooming of the skin in contact with the subcutaneous port of the SUB system. S. schleiferi was detected in a severe abscess in the cutaneous wound, and skin necrosis was observed. As bacterial contamination of the SUB system was suspected, the SUB system was removed from the cat. Scanning electron microscopy analysis revealed biofilm formation inside the locking loop catheters and outside the subcutaneous port of the SUB system. In an in vitro assay, S. schleiferi isolated from a catheter of the SUB system had low biofilm-forming ability. After the SUB system was removed, S. schleiferi was not detected in the urine and the infection was completely cured.

CONCLUSION: Considering these results, bacterial infections in cats with SUB systems should be carefully monitored, as contamination by biofilm-forming bacteria can occur regardless of flushing frequency.

RevDate: 2025-10-02

Jabrodini A, Yazdanpanah S, Malekzadeh M, et al (2025)

Virulence factors of Candida spp. isolated from COVID-19 patients: hydrolytic enzyme activity and biofilm formation.

BMC microbiology, 25(1):611.

During the coronavirus disease 2019 (COVID-19) pandemic, an increased prevalence of Candida co-infections has been reported. However, data on the virulence factors of Candida spp. isolated from COVID-19 patients remain scarce. This study aimed to assess the virulence factors of Candida spp. isolated from COVID-19 patients and to explore their potential associations with clinical parameters. A total of 71 Candida (C.) strains were analyzed, representing four species: 49 (69.01%) C. albicans strains, 14 (19.71%) C. glabrata strains, 7 (9.85%) C. tropicalis strains, and 1 (1.40%) C. dubliniensis strain. The activities of proteinase, phospholipase, and hemolysin, as well as biofilm-forming capacity, were evaluated. All C. albicans strains and 21 (95.45%) non-albicans Candida (NAC) strains produced proteinase. Phospholipase activity was detected in 46 (93.87%) C. albicans strains and 10 (45.45%) NAC strains. High hemolytic activity was observed in all Candida strains. Biofilm formation was detected in 31 (43.66%) Candida strains, with variable intensities. These findings highlight high levels of hydrolytic enzyme activity among Candida spp. isolated from COVID-19 patients and contribute to the growing understanding of Candida pathogenesis in immunocompromised populations, providing insights for patient management.

RevDate: 2025-10-02
CmpDate: 2025-10-02

Chowdhury SR, Hosen M, Hossain H, et al (2025)

Biofilm production and virulence traits among extensively drug-resistant and methicillin-resistant Staphylococcus aureus from buffalo subclinical mastitis in Bangladesh.

Scientific reports, 15(1):34425.

Methicillin-resistant Staphylococcus aureus (MRSA) is a critical pathogen implicated in subclinical mastitis (SCM), a hidden threat to dairy productivity. This study investigated the prevalence, antibiotic resistance profiles, and virulence traits of MRSA from SCM-affected riverine buffaloes in Jamalpur, Bangladesh. A total of 344 milk samples were screened using the California Mastitis Test (CMT) and Modified Whiteside Test (MWST). Among the milk samples, 46.5% were positive for SCM by CMT. Culture, biochemical tests, and PCR confirmed 73 (21.2%) Staphylococcus spp., of which 30 (41.1%) were identified as S. aureus and 43 (58.9%) as non-aureus staphylococci (NAS). Among the 30 S. aureus-positive isolates, 10 (33.3%) were identified as methicillin-resistant S. aureus (MRSA), corresponding to a prevalence of 2.9% among the total milk samples. The MRSA isolates exhibited high multidrug resistance, especially to tetracycline (80%) and cefoxitin (80%), and commonly harbored resistance genes such as tetA (80%), aac(3)-iv (70%), and sul1 (50%). Virulence genes hla (66.7%) and sea (50%) were frequently detected, while icaA was found in 23.3% of MRSA. Notably, 60% of MRSA isolates were categorized as XDR based on international standard definitions, while 60% were biofilm producers with high MARI values up to 0.92, indicating severe resistance potential. These findings underscore a significant burden of MDR/XDR MRSA with virulence potential in buffalo SCM, posing serious risks to animal and public health.

RevDate: 2025-10-02

Mei N, Jia F, Liu Y, et al (2025)

Achieving partial nitritation-anammox in membrane-aerated biofilm reactor by hydroxylamine addition.

Journal of environmental management, 394:127404 pii:S0301-4797(25)03380-8 [Epub ahead of print].

The membrane-aerated biofilm reactor (MABR) is naturally suitable for partial nitritation-anammox (PN/A) because aerobic and anaerobic microorganisms can grow in different biofilm layers. However, suppressing nitrite-oxidizing bacteria (NOB) in the oxygen-rich inner MABR biofilms remains challenging, while anammox bacteria (AnAOB) in the outer layer are more vulnerable to many harsh treatments. This study demonstrated the strategy of applying hydroxylamine (NH2OH) to achieve stable PN/A in MABR. Over 250 days, long-term experiments showed that low dissolved oxygen (0.06-0.20 mg L[-1]) could not suppress NOB, while both continuous and intermittent 10 mg L[-1] NH2OH addition not only achieved effective NOB suppression but also significantly promoted ammonia-oxidizing bacteria and AnAOB. Consequently, the nitrogen removal efficiency increased from 74.0 ± 1.1 % to 91.7 ± 1.6 %. Fundamentally, NH2OH addition rapidly changed the transcription levels of key functional genes in membrane biofilms, resulting in a significant decrease in nxrB transcription level by 68.6 ± 3.8 % and an increase in those of amoA and hzsB by 1835.8 ± 307.2 % and 314.2 ± 112.7 %, respectively. NH2OH addition resulted in the temporary accumulation of hydrazine and nitric oxide at low levels, which collectively contributed to NOB suppression. Particularly, Nitrospira, "Ca. Nitrotoga" and Nitrolancea (all three distinct NOB genera present in MABR biofilm) relative abundances decreased by 48.6 ± 7.5 %, 10.8 ± 2.5 %, and 75.0 ± 6.8 % respectively, which alleviated NOB adaptation risk. Therefore, NH2OH can be used to support NOB suppression in MABR.

RevDate: 2025-10-02

Yang X, Zhang L, Xu L, et al (2025)

Triboelectric nanogenerator-based strategy for preventing biofilm formation in orthopedic applications.

Biochemical and biophysical research communications, 786:152726 pii:S0006-291X(25)01442-1 [Epub ahead of print].

Orthopedic implant-associated infections constitute one of the most challenging complications in musculoskeletal surgery, largely attributable to the formation of tenacious bacterial biofilms. These biofilms demonstrate inherent resistance to conventional antibiotic therapies and evade host immune mechanisms. Current prophylactic approaches-such as systemic or localized antibiotic delivery and surface modifications-often fail to establish a durable protective barrier. Moreover, their efficacy is increasingly compromised by the escalating global crisis of antimicrobial resistance. Herein, we present a self-powered antibacterial system that integrates a triboelectric nanogenerator (TENG) with titanium-based orthopedic implants, capable of harvesting biomechanical energy from daily movement and delivering localized electrical stimulation. The TENG outputs peak voltages up to 140 V, sufficient to generate localized electric fields that induce bacterial migration and disrupt membrane integrity. Finite element simulations confirmed a robust electric potential difference between titanium and platinum electrodes, guiding bacterial repulsion away from the implant surface. In vitro assays demonstrated significant inhibition of Escherichia coli biofilm formation (∼34.6 % reduction), accompanied by morphological disruption of bacterial colonies. In vivo, TENG-driven stimulation accelerated wound healing, reduced bacterial coverage on implant surfaces by ∼12.6 %, and alleviated inflammatory infiltration in peri-implant tissues. Collectively, these findings establish a proof-of-concept for TENG-powered antibacterial orthopedic implants, offering a sustainable, biocompatible, and antibiotic-free strategy to combat implant-associated infections.

RevDate: 2025-10-02

Kang HJ, You J-Y, Kim SH, et al (2025)

Genetic diversity, virulence genes, antimicrobial resistance, and biofilm formation of Klebsiella pneumoniae isolated from bovine mastitis milk in South Korea.

Microbiology spectrum [Epub ahead of print].

Klebsiella pneumoniae, a zoonotic agent, is a causative pathogen of bovine mastitis. Despite its clinical relevance in dairy farms, studies on K. pneumoniae in bovine mastitis remain limited. Additionally, studies on K. pneumoniae's genetic diversity and virulence characteristics in South Korea remain limited. Therefore, in this study, we aimed to elucidate the genetic diversity, antimicrobial resistance, virulence genes, and biofilm-forming capacity of 29 K. pneumoniae strains isolated from bovine mastitis milk samples in South Korea between 2017 and 2023. Multilocus sequence typing revealed 23 sequence types, four of which were novel, indicating substantial genetic heterogeneity and the absence of a dominant clonal lineage. Excluding intrinsic resistance, the highest resistance rates were observed for tetracycline (34.5%) and sulfisoxazole (31.0%), whereas resistance to the other antibiotics tested ranged from 0% to 20.7%. In addition, multidrug resistance (MDR) was noted in 20.7% of isolates. Virulence gene analysis revealed that most isolates carried the ureA, uge, wabG, and fimH genes, whereas allS, rmpA, iucB, and iroNB were not detected. Two isolates exhibited a hypermucoviscous phenotype, and one belonged to the capsular serotype K2. All isolates demonstrated biofilm-forming ability, with moderate-to-strong production observed in over 89.0% of cases, indicating potential for persistence and treatment challenges. In conclusion, K. pneumoniae isolates from mastitis milk carried multiple virulence genes and showed MDR as well as robust biofilm formation. Therefore, continued surveillance and further characterization of K. pneumoniae are needed to support mastitis control and protect public health.IMPORTANCEKlebsiella pneumoniae is an emerging environmental pathogen associated with clinical mastitis in dairy cows, raising concerns regarding antimicrobial resistance and public health. To the best of our knowledge, this study provides the first comprehensive characterization of K. pneumoniae isolates from mastitis milk in South Korea, including analyses of genetic diversity, antimicrobial resistance, virulence factors, and biofilm formation. The findings advance our current understanding of K. pneumoniae associated with bovine mastitis and highlight the need for continued surveillance that will contribute to mastitis control efforts and safeguard public health.

RevDate: 2025-10-01

Pendor O, Ukey S, Trivedi R, et al (2025)

Transcriptomic insights into biofilm dynamics and therapeutic targets in chronic wound infections (MIMET 107281).

Journal of microbiological methods pii:S0167-7012(25)00197-6 [Epub ahead of print].

Chronic wound infections remain a significant clinical challenge, primarily due to the formation of bacterial biofilms that hinder healing and increase antimicrobial resistance. This review explores various studies focused on biofilm development, transcriptional responses, and therapeutic strategies for combating biofilm-associated infections. Using Pseudomonas aeruginosa PAO1 in ex vivo porcine skin wound models, RNA-seq analysis revealed key genes involved in biofilm formation, notably the lapA gene encoding alkaline phosphatase, which was upregulated, while denitrification pathway genes such as nirS were downregulated. Targeting these pathways through NO induction showed potential for biofilm disruption. Novel biofilm-inhibiting strategies, including silver nanoparticles, lactoferrin, and exopolysaccharides, demonstrated antibacterial, anti-biofilm, and wound-healing effects. Additionally, metal-based nanozymes (Ru-procyanidin nanoparticles) and microneedle patches embedded with cerium/zinc composites emerged as promising solutions for oxidative stress reduction and bacterial elimination in diabetic wounds. Omics approaches, particularly transcriptomics and metabolomics, have further elucidated biofilm differentiation mechanisms and host-pathogen interactions. Advanced detection methods such as electrochemical biosensors and peptide nucleic acid fluorescent in situ hybridization (PNA-FISH) have improved the identification of biofilm-associated infections. Furthermore, comparative analyses of mixed-species and single-species biofilms highlighted their differential impact on wound healing, with polybacterial biofilms causing more severe impairment. These findings underscore the importance of integrating RNA-based diagnostics, molecular therapies, and novel biomaterials to enhance chronic wound management. Future research should focus on translating these insights into clinical applications for more effective biofilm-targeted treatments.

RevDate: 2025-10-01

Díaz-Navarro M, Crespo A, Muñoz P, et al (2025)

Biomass and metabolic activity staining biofilm techniques are not reliable enough to be used in microbiology laboratories.

Journal of microbiological methods pii:S0167-7012(25)00201-5 [Epub ahead of print].

Crystal violet and XTT staining quantify biofilms but are influenced by external factors. Testing MSSA, E. coli, and C. albicans refrigerated five weeks revealed weekly variability between researchers. These methods need careful interpretation and should be supported by more reproducible techniques for reliable results.

RevDate: 2025-10-01

Namazi P, Behbahani BA, Noshad M, et al (2025)

Anti-Listeria Mechanisms, Safety, and Predictive Modeling of Lacticaseibacillus casei UTMB9: Probiotic Profiling Targeting Virulence Gene Expression and Biofilm Formation.

Microbial pathogenesis pii:S0882-4010(25)00796-X [Epub ahead of print].

There is growing interest in probiotics due to their potential to confer health benefits. This study aimed to explore the potential probiotic characteristics, gene expression linked to biofilm formation, and anti-biofilm properties of Lacticaseibacillus casei UTMB9. L. casei UTMB9 tolerates acidic environments, with survival rates of 6.90, 7.59, and 7.96 log CFU/mL at pH 2.5, 3.5, and 4.5, respectively, and exhibits slight growth inhibition under bile concentrations up to 0.7 %. Viability declined modestly from 8.51 to 6.61 log colony forming unit (CFU)/mL under simulated gastrointestinal conditions. Surface hydrophobicity (40.9 %), auto-aggregation (30.9 %), co-aggregation (40.8 %), and adhesion (11.9 %) support its adherence potential. Antimicrobial assays showed most potent inhibition against Listeria monocytogenes (9.70 mm) versus E. coli (4.74 mm). Scanning Electron Microscopy (SEM) imaging revealed pronounced damage to L. monocytogenes cells after exposure to cell-free supernatant (CFS), accompanied by significant downregulation of prfA and flaA, and marked antibiofilm suppression. It also demonstrated antioxidant activity (2,2-diphenyl-1-picrylhydrazyl (DPPH) 43.6 %, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) 47.5 %, linoleic acid oxidation inhibition 30.3 %) and moderate anticancer activity (IC50 ≈ 55-62 mg/mL). The strain reduced cholesterol uptake by 41.9 %, was broadly antibiotic-sensitive (except for partial resistance to ampicillin), and lacked biogenic amine production, DNase, or hemolytic activity. In the second part of this study, Gaussian Process Regression (GPR) was used to predict acidity and bile salt. GPR accurately predicted acidity and bile tolerance (MAPE = 0.22 % and 0.18 %; R[2]≥ 0.99). These findings position L. casei as a promising probiotic agent with robust antimicrobial, antibiofilm, antioxidant, and predictive model-supported features.

RevDate: 2025-10-01

Ashrafi B, Heydari R, Rezaei F, et al (2025)

Investigating the release of active compounds and cytotoxicity of thymol/gallic acid/β-cyclodextrin bio-nanocomposite: a targeted strategy with the approach of disrupting the genes involved in the quorum sensing system and biofilm formation in P. aeruginosa (PAO1).

Preparative biochemistry & biotechnology [Epub ahead of print].

The quorum sensing (QS) system and cell-to-cell communication have had a significant impact on biofilm formation and virulence factor increase in Pseudomonas aeruginosa (P. aeruginosa), making this opportunistic pathogen a global concern and potentially life-threatening agent. The present study aimed to create an innovative pharmaceutical bio-nanocomposite (BNC) comprising thymol (THY) and gallic acid (GA) based on β-cyclodextrin (β-CD), which was used to investigate the release kinetics of active compounds, the level of cytotoxicity, antibacterial and anti-biofilm potential, and measuring the expression of genes effective in QS in the strain PAO1 pays P. aeruginosa. Based on this, physicochemical characteristics of the synthesized BNC were determined using Fourier transform infrared spectroscopy analysis (FTIR), UV-vis measurement, dynamic light scattering (DLS), zeta potential, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The BNC's antibacterial and anti-biofilm capabilities were assessed using the PAO1 reference strain of P. aeruginosa and the expression level of QS-effective genes (rhlI, rhlR, lasI, and lasR) in bacteria was also evaluated in the presence of the synthesized BNC. The results of FTIR spectroscopy show the formation of intramolecular hydrogen bonds between THY, GA and β-CD. Absorption peaks of the UV-vis spectroscopy spectrum of the synthesized BNC at wavelengths of 217 and 272 nm are confirmed successful encapsulation of the THY and GA into the β-CD. The maximum size of the synthesized BNC was recorded as 356.3 nm with a polydispersity index (PDI) of 0.816. SEM and TEM micrographs show the presence of THY/GA active compounds in the pores in β-CD and the formation of a dense polymer network. After 360 minutes of release kinetics, more than 70% of the complex's active chemicals had been released. The biological complex's low toxicity is indicated by average cell survival of more than 65% and the ability to preserve the spindle shape of normal fibroblast cells at high concentrations. The PAO1 strain has minimum inhibitory concentrations (MIC) of 323 and 199.6 μg/mL for minimal biofilm inhibition concentration 50% (MBIC50). The decrease in rhlI and rhlR gene expression relative to the control group (without treatment) suggests that the active chemicals released from the biological complex interact and disrupt the QS pathway. Overall, the synthesized pharmaceutical complex has promise as a clever and effective option for future research and practical advances, as well as the development of complementary therapies.

RevDate: 2025-10-01
CmpDate: 2025-10-01

Kurtzman GM, Horowitz RA, Johnston R, et al (2025)

Oral Biofilm and Gender-Specific Health Considerations.

Cureus, 17(8):e91289.

Oral biofilm plays a central role in the development of periodontal and systemic diseases, with growing evidence highlighting significant gender-specific differences. Hormonal fluctuations in women, during puberty, menstruation, pregnancy, menopause, and with oral contraceptive use, may alter the composition and behavior of oral biofilm, increasing susceptibility to gingival inflammation and periodontal disease. Conditions such as polycystic ovary syndrome (PCOS), osteoporosis, and pregnancy-associated gingivitis further demonstrate the influence of endocrine factors on oral health. In men, higher rates of severe periodontitis are observed, potentially linked to testosterone-related immune responses and behavioral factors with associations to lower sperm counts, increased incidence of prostate cancer, and erectile dysfunction. These distinctions underscore the importance of considering sex-specific biology in both the prevention and management of oral and systemic diseases influenced by biofilm. This study reviews the connections between gender-specific health and oral biofilm.

RevDate: 2025-10-01
CmpDate: 2025-10-01

Jana D, Manna T, Guchhait KC, et al (2025)

An investigation on anti-biofilm potential of Aegle marmelos fruit extract against multi-drug-resistant Staphylococcus aureus.

BMC complementary medicine and therapies, 25(1):334.

BACKGROUND: Staphylococcus aureus, member of ESKAPEE pathogens is a noteworthy contributor to the global crisis rising due to antimicrobial resistance. Biofilms are the primary reason behind the increased antibiotic resistance and tolerance of pathogens. Hence targeting bacterial biofilms has been prioritized as an alternative strategy to counter antibiotic resistance. Aegle marmelos has gained prominence in Indian traditional medicine as seeds, fruits, leaves, bark and roots of this plant are being in use extensively in treating several kinds of ailments by the inhabitants of this subcontinent due to its ethno-pharmacological relevance. The fruit of this plant has been found with remarkable anti-bacterial properties along with other therapeutic efficacies. The present study aimed to identify the anti-biofilm potential of methanolic fruit extract of Aegle marmelos (AMFE) against multi-drug-resistant (MDR) S. aureus strains as a resort to counter the global crisis of antimicrobial resistance for alternative approaches.

RESULTS: MBIC and MBEC of AMFE ranged between 100 and 200 µg.mL[-1] and 300-500 µg.mL[-1], respectively. AMFE could substantially reduce the carbohydrate and protein content of the exo-polymeric substance (EPS), crucial for biofilm production. Expressions of major biofilm promoting genes icaAD and its accessory sarA were down-regulated upon AMFE treatment as revealed from qRT-PCR analysis whereas the quorum sensing gene agr that promotes biofilm detachment was up-regulated. Fluorescence, scanning electron and atomic force microscopic studies confirm the reduction of biofilm biomass upon AMFE treatment. Up to 10 mg.mL[-1] AMFE was non-toxic to human lymphocytes with cell viability of 75.35%. GC-MS and FT-IR studies could detect the bioactive components where 9-octadecenoic acid, n-hexadecanoic acid, 9,12-octadecadienoic acid, methyl 4,7,10- hexadecatrienoate were the major components.

CONCLUSION: Anti-biofilm activity of AMFE towards MDR S. aureus have been established through in vitro biochemical and gene expression studies that were further substantiated by microscopic studies which reveal that AMFE could be explored in the management of S. aureus-associated infections.

RevDate: 2025-10-01

Soltane R (2025)

Pubescine as a Novel Antibacterial Agent Against Vancomycin-Resistant Enterococcus: Growth Inhibition, Antibiotic Synergy, and Anti-Biofilm Activity.

Current pharmaceutical biotechnology pii:CPB-EPUB-150818 [Epub ahead of print].

INTRODUCTION: The rise of Vancomycin-Resistant Enterococcus (VRE) has become a major public health concern due to its resistance to conventional antibiotics and ability to form biofilms. The urgent need for novel therapeutic strategies has led to increased interest in natural compounds with antimicrobial potential. Pubescine (PBN), a steroidal alkaloid isolated from Holarrhena pubescens, has demonstrated antimicrobial properties, but its efficacy against VRE remains unexplored.

METHODS: PBN was isolated and purified from Holarrhena pubescens using chromatographic techniques and identified through spectroscopic analysis. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were determined via broth microdilution assays. Time-kill assays assessed the bacteriostatic or bactericidal nature of PBN. Resistance development was evaluated through prolonged bacterial exposure to subinhibitory concentrations. Synergistic interactions with vancomycin and cefoxitin were analyzed using checkerboard microdilution assays. Biofilm formation and eradication were assessed via crystal violet staining and fluorescence imaging. Metabolic activity and oxidative stress induction were measured using the Alamar Blue assay and Reactive Oxygen Species (ROS) quantification, respectively.

RESULTS: PBN exhibited concentration-dependent inhibition of VRE growth, primarily exerting a bacteriostatic effect without promoting the development of resistance. Checkerboard assays revealed strong synergy between PBN and vancomycin (FICI = 0.1875) and cefoxitin (FICI = 0.3125), suggesting that PBN enhances the efficacy of these antibiotics.

DISCUSSION: PBN significantly reduced biofilm formation and facilitated biofilm disruption at concentrations as low as 4 μg/mL. Metabolic assays demonstrated that PBN suppresses bacterial metabolic activity, while ROS quantification indicated a substantial increase in oxidative stress, suggesting a multi-targeted mechanism of action.

CONCLUSION: These findings establish PBN as a promising antimicrobial agent with potent activity against vancomycin-resistant Enterococcus faecalis. Its ability to enhance antibiotic efficacy, inhibit biofilm formation, and induce oxidative stress underscores its potential as a novel therapeutic strategy against multidrug-resistant infections. Further in vivo studies and pharmacokinetic evaluations are warranted to assess its clinical applicability.

RevDate: 2025-10-01
CmpDate: 2025-10-01

Veerabathiran A, Subramania AK, Saikia M, et al (2025)

Development of 3D-printed Ti-MXene incorporated chitosan/HAP nano-composite soft-bone scaffold and its mechanical, anti-biofilm and cell-viability studies.

Scientific reports, 15(1):33762.

The prevailing scientific literature suggests that implantable plates demand resurgery, and it will result in corrosion behaviour and the formation of biofilm on the scaffold by Staphylococcus aureus, which is capable of causing a bone surgery-related detrimental effect in two-thirds of the people suffering from osteomyelitis diseases. The development of a nanocomposite scaffold by 3D-bioprinting to improve potent mechanical features with substantial biological characteristics. By incorporating hydroxyapatite (10% w/v) into chitosan (10% w/v) at 1:1 ratio mimicking the natural structure of soft bone tissue. Furthermore, a better structural hydrogel was synthesized for 3D bio-printing through the incorporation of Ti-MXene into the Chitosan/Hydroxyapatite nanocomposite at two distinct ratios. Apart from this, 0.3 mg/mL of Ti-MXene containing 3D-printed nanocomposite scaffold revealed better structural morphology with very less biofilm formation when compared to other 3D-printed scaffolds. Furthermore, mechanical testing such as tensile revealed 23.3 MPa for 0.3 mg/mL of Ti-MXene incorporated Chitosan/HAP nanocomposite. Additionally, this scaffold exhibits a favorable contact angle (74.70°) with a low swelling ratio (27.6%) and degradation rate (1.1%). Further, an in-vitro cell viability test showed a higher cell attachment without cell death. These results find the absence of toxic effect and suggest an enhancement in cell attachment.

RevDate: 2025-10-01
CmpDate: 2025-10-01

Kashyap S, Rathod Y, S Biswas (2025)

Murraya koenigii methanolic extract inhibits bacterial growth and biofilm of Staphylococcus aureus and Enterococcus faecalis.

Scientific reports, 15(1):34056.

Hospital-acquired infections caused by Staphylococcus aureus and Enterococcus faecalis are significant global health challenges due to their biofilm-forming ability, also contributing to the derived antibiotic resistance and environmental persistence. This growing resistance poses serious global health challenges, emphasizing the need for better surveillance and new treatments. Plant-derived bioactives have emerged as possible therapeutics to such opportunistic pathogens and they are potential alternatives to traditional antimicrobials. This study investigates the in vitro activity of Murraya koenigii's methanolic (MKM) leaf extract and its compounds against the growth and biofilm-forming ability of S. aureus and E. faecalis. Results revealed that the MKM extract effectively inhibited the growth of S. aureus and E. faecalis at their respective MIC levels. Furthermore, flow cytometry and confocal imaging demonstrated substantial membrane damage in MKM-treated cells compared to DMSO-treated and untreated controls. Additionally, the MKM extract significantly disrupts biofilm formation and leads to reduced extracellular polymeric substance (EPS) production. Scanning electron microscopy provided visual evidence of disrupted biofilm architecture following MKM extract treatment. HR-LC/MS analysis identified bioactive compounds within the extract, which were further evaluated for drug-likeness properties through ADME analysis. In silico molecular docking studies confirmed strong binding affinities of MKM-derived compounds with key biofilm-related receptor proteins, SpA in S. aureus and Esp in E. faecalis. These findings highlight the significant potential of MKM extract as a novel and effective phytotherapeutic resource for developing strategies to combat biofilm-associated infections.

RevDate: 2025-09-30
CmpDate: 2025-10-01

Rafique A, Baig N, Naim A, et al (2025)

Utilization of clove and cinnamon essential oils as an alternative to inhibit MDR and biofilm producing E. coli from raw chicken meat.

Scientific reports, 15(1):34079.

The microbial contamination and spoilage found in chicken meat is responsible for food-borne illnesses and outbreaks leading to hospitalizations. E. coli is the most commonly reported microorganism. The dissemination of bacterial strain with biofilm-formation ability and resistance to antimicrobials at the end of the food chain is a global concern; as well. Eco-friendly and novel means like essential oils are required to break these vicious patterns and ensure the longevity of quality food products. The study aimed to probe the prevalence, pattern of antimicrobial resistance and the biofilm formation ability in E. coli isolated from chicken meat samples. It also explored the antimicrobial and anti-biofilm formation ability of clove and cinnamon essential oils. 150 chicken meat samples from different localities of Karachi, Pakistan were isolated and identified by selective culturing and conventional microbiological techniques. Following antibiogram analysis, antibacterial activity of clove and cinnamon essential oils was evaluated. Putative biofilm production ability was also explored using the test tube, microplate reader, and scanning electron microscopy. Finally, the molecular characterization of potentially strong biofilm producers was done along with exploration of the pathogenic gene (PapC). 49 chicken meat samples out of 150 were contaminated with E. coli. 90% (44 isolates) of E. coli were multidrug resistant. 59.2% (29 isolates) were biofilm producers (BPs). Out of 29 BPs, nine (31%) were strong biofilm producers (SBPs). No significant correlations were observed between antimicrobial resistance and biofilm producing ability of E. coli isolates (p value ≥ 0.05). 40% of SBPs were inhibited when subjected to both clove (MIC: 250 to 500 µL/mL) and cinnamon (MIC: 62.5 µL/mL) EOs. Activity of both neat CO and CinO had no significant difference (p value ≥ 0.05). The identity of 3 SBPs (Strains: AR11E, AR12E and AR22E) were further confirmed by molecular identification (16SrRNA) and SEM revealed potential degradation of the bacterial cells with a reduction in count when treated with CinO and CO. Only one strain (AR22E) was positive for the papC gene. The prevalence of E. coli and strong-biofilm producers in retail chicken meat was not very high; however, the majority of the isolates were multi-drug resistant. Therefore, it is important to keep a tab on the prevalence of these commensal and pathogenic microorganisms in retail chicken meat since they are an exposure site close to the consumer. The use of alternative means like essential oils in poultry, meat and meat-products is a good strategy since they have proven efficacy against pathogenic E. coli.

RevDate: 2025-09-30
CmpDate: 2025-09-30

Choudhary J, M Shariff (2025)

Characterization of carbapenem-resistant biofilm forming Acinetobacter baumannii isolates from clinical and surveillance samples.

Scientific reports, 15(1):33892.

Acinetobacter baumannii (A. baumannii) is an important nosocomial pathogen responsible for a wide range of human infections. The emergence of multidrug resistance (MDR) causes life-threatening nosocomial infections. Also, the formation of biofilm helps it survive on abiotic surfaces and is transferred through healthcare workers, thereby causing nosocomial infections. Hence, we study the current antibiotic resistance patterns and virulence factors in our clinical and colonizing isolates. A total of 92 isolates (44 colonizing and 48 clinical) of A. baumannii were included in the study. Antibiotic susceptibility testing was performed by VITEK 2. Biofilm formation was assessed by the tissue culture plate method. Polymerase chain reaction (PCR) for oxacillinases, MBLs and biofilm-associated genes were performed. Meropenem resistance was found in 42 (87.5%) of the clinical and 44 (97.7%) of the colonizing isolates. A strongly adherent biofilm was produced by 11 (22.91%) of the clinical and 12 (27.27%) of the colonizing isolates. Biofilm-associated genes, ompA, bap and csuE were present in 45 (93.7%), 47 (97.9%) and 44 (91.6%) of the clinical isolates, respectively and in all the colonizing isolates. blaOXA23-like was more prevalent in colonizing than clinical isolates. blaOXA-58-like and blaOXA-24-like were present in very few isolates. The presence of metallo beta-lactamase (MBLs) was observed to be lower than oxacillinases. NDM1 was present in 15.29%, SIM in 27%, GIM in 14.11%, VIM in 32.9%, SPM in 5.8%, and IMP in 1.2% of the meropenem-resistant isolates. Carbapenem resistance (XDR) is increasing in A.baumannii. Biofilm formation is an important virulence factor responsible for its survival in the hospital environment and causes nosocomial infections. Biofilm-producing isolates were also found to be carbapenem-resistant. Strict disinfection procedures are to be followed to prevent its spread in the hospital.

RevDate: 2025-09-30
CmpDate: 2025-09-30

Nebo UC, Arotupin DJ, AO Olalemi (2025)

Biodegradation of heavy petroleum polycyclic aromatic hydrocarbons (PAHs) in polluted soil by biofilm-forming Bacillus tropicus UCB and Pseudomonas aeruginosa SYLI isolated from crude oil-contaminated sludge.

Biodegradation, 36(5):97.

Crude oil pollution poses a threat to soil ecosystems, particularly in oil-producing regions. This study assessed the biodegradation potential of biofilm-forming Bacillus tropicus UCB and Pseudomonas aeruginosa SYLI isolated from crude oil sludge. Sludge samples were seasonally collected and bacterial counts determined using standard methods while microbial enrichment was conducted in mineral salt medium containing 1% crude oil. Biofilm formation was assessed using Congo red agar and microplate assays. Isolates were identified through cultural, biochemical, and 16S rDNA analysis. Dose-response toxicity test examined degradation across 1%, 3%, 7%, and 10% crude oil concentrations, while PAHs degradation in soil microcosm was analysed using GC-MS. Seasonal variations significantly influenced bacterial populations, with highest count (1.53 × 10[8] CFU/mL) in the dry season and the least 3.17 × 10[6] CFU/mL) during wet season. Optical density peaked at 2.86 nm in enrichment III. Results revealed molecular identities of the isolates as B. tropicus UCB and P. aeruginosa SYLI. Both isolates metabolized crude oil from 1 to 10%, with B. tropicus producing 601 mg/L CO2 with 10% at day 12 and P. aeruginosa yielding 616 mg/L with 1% at day 4. In addition, results showed over 99% removal of low molecular weight PAHs and 75% degradation of high molecular weight PAHs, upon biostimulation. These findings highlight complementary strengths of B. tropicus on high-oil loads and P. aeruginosa rapid initial degradation at lower concentrations. This study suggests that biofilm formation coupled with biostimulation may improve bacterial efficiency in bioremediation. It also represents the first in vitro report on PAHs degradation by Bacillus tropicus.

RevDate: 2025-09-30

Suyama H, Luu LDW, Zhong L, et al (2025)

Proteomic comparison of epidemic Australian Bordetella pertussis biofilm cells.

Microbiology spectrum [Epub ahead of print].

Bordetella pertussis causes whooping cough, a severe respiratory infectious disease. Studies have compared the currently dominant single nucleotide polymorphism (SNP) cluster I (pertussis toxin promoter allele, ptxP3) and previously dominant SNP cluster II (ptxP1) strains as planktonic cells. Since biofilm formation is linked with B. pertussis pathogenesis in vivo, this study compared the biofilm formation capabilities of representative strains of cluster I and cluster II. Confocal laser scanning microscopy found that the cluster I strain had a denser biofilm structure compared to the cluster II strain. Differences in protein abundance of the biofilm cells were then compared using tandem mass tagging and high-resolution multiple reaction monitoring. In total, 1,453 proteins were identified, of which 40 proteins had significant differential abundance between the two strains in biofilm conditions. Of particular interest was a large increase in the abundance of energy metabolism proteins (cytochrome proteins PetABC and BP3650) in the cluster I strain. When the abundance of these proteins was compared between six additional strains from each cluster, it was found that the protein abundance varied between all strains. These findings suggest that there are large levels of individual proteomic diversity between B. pertussis strains in biofilm conditions despite the highly conserved genome of the species. Overall, this study revealed visual differences in biofilm structure between B. pertussis strains and highlighted strain-specific variation in protein abundance that dominates potential cluster-specific changes that may be linked with the dominance of cluster I strains.IMPORTANCEBordetella pertussis causes whooping cough. The currently circulating cluster I strains have taken over previously dominant cluster II strains. It is important to understand the reasons behind this evolution to develop new strategies against the pathogen. Recent studies have shown that B. pertussis can form biofilms during infection. This study compared the biofilm formation capabilities of a cluster I and a cluster II strain and identified visual differences in the biofilms. The protein abundance between these strains grown in biofilms was compared, and proteins identified with varied abundance were measured with additional strains from each cluster. It was found that despite the highly conserved genetics of the species, there was varied protein abundance between the additional strains. This study highlights that strain-specific variation in protein abundance during biofilm conditions may dominate the cluster-specific changes that may be linked to the dominance of cluster I strains.

RevDate: 2025-09-30
CmpDate: 2025-09-30

Yang SB, Ku D, Moon JH, et al (2025)

Complete genome sequence of Streptococcus hominis isolated from subgingival biofilm.

BMC genomic data, 26(1):69.

OBJECTIVE: Streptococcus hominis is a recently described species within the genus Streptococcus, yet its genomic characteristics remain poorly understood, particularly in the context of the oral microbiome. Previously, only two complete genomes from non-oral sources were available. To address this gap, we sequenced and analyzed S. hominis strain KHUD_010, isolated from the subgingival biofilm of a healthy Korean adult.

DATA DESCRIPTION: Genomic DNA from KHUD_010 was extracted and confirmed as S. hominis by 16 S rRNA gene sequencing. Whole-genome sequencing using the PacBio Sequel II platform generated 135,974 HiFi reads (N50: 10,345 bp). De novo assembly with SMRT Link v11.0 produced a single circular chromosome of 1,883,665 bp with 39.04% GC content. Annotation via the NCBI Prokaryotic Genome Annotation Pipeline predicted 1,793 protein-coding genes, four rRNA operons (5 S, 16 S, 23 S), and 120 tRNAs. BUSCO analysis showed 99.1% completeness. Comparative genomics with NSJ-17 and UMB6992B revealed 1,416 core, 223 dispensable, and 398 strain-specific gene clusters. KHUD_010 harbored 18 unique gene clusters comprising 20 genes, mostly assigned to COG category L (replication, recombination, repair). This high-quality genome expands the genomic landscape of S. hominis and provides a valuable reference for future studies on oral microbiome diversity and host adaptation.

RevDate: 2025-09-29
CmpDate: 2025-09-29

Lordejani AS, Tajbakhsh E, Khamesipour F, et al (2025)

Prevalence, Antibiotic Resistance, and Biofilm Formation of Proteus mirabilis in Dairy Products: Implications for Veterinary and Public Health.

Veterinary medicine and science, 11(6):e70600.

Dairy products are essential components of human and animal nutrition, providing vital nutrients such as proteins, vitamins and minerals. However, their susceptibility to microbial contamination, particularly by pathogens like Proteus mirabilis, poses significant risks to both animal and public health. This study investigated the prevalence, antibiotic resistance patterns and biofilm-forming ability of P. mirabilis in various dairy products, with a focus on raw milk, in Shahrekord, Iran. A total of 480 samples, including raw cow, goat and sheep milk, as well as cheese, yogurt, cream, curd and a traditional Iranian fermented yogurt-based beverage (doogh), were analysed under controlled laboratory conditions. The findings revealed a 12.29% prevalence rate of P. mirabilis, with raw cow's milk showing the highest contamination rate (21.66%). Among the isolates, 88.12% were capable of forming biofilms, and 71.15% exhibited strong biofilm production. Antibiotic susceptibility testing identified a high prevalence of multidrug-resistant strains, with the highest resistance rates observed for cotrimoxazole (59.32%) and gentamicin (50.84%). In addition, 25.42% of the isolates were identified as extended-spectrum beta-lactamase (ESBL) producers, with blaCTX-M being the most prevalent resistance gene. A significant correlation was found between biofilm-forming ability and the presence of antibiotic resistance genes, highlighting the dual challenges of microbial persistence and antimicrobial resistance. These findings emphasize the need for improved hygiene practices in dairy production, targeted biofilm-disrupting strategies and enhanced surveillance programs to mitigate risks to both animal and public health. This study provides critical insights for veterinary professionals and policymakers to develop effective interventions aimed at reducing contamination and combating antimicrobial resistance in dairy products.

RevDate: 2025-09-29

Shan W, Du F, Zhang H, et al (2025)

D-histidine exhibited anti-biofilm activity against Aggregatibacter actinomycetemcomitans.

Microbiology spectrum [Epub ahead of print].

Aggregatibacter actinomycetemcomitans is a key pathogen implicated in periodontitis. The bacterium in biofilms exhibits significant resistance to antimicrobial agents and host immune responses compared to its planktonic form, posing a major challenge for periodontal therapy. Recently, D-histidine has emerged as a promising anti-biofilm agent against Pseudomonas aeruginosa infections. However, its potential application in the oral field remains unexplored. This study investigated the anti-biofilm effect of D-histidine on A. actinomycetemcomitans and examined its influence on the expression of virulence factor genes to elucidate possible underlying mechanisms. Our results demonstrated that D-histidine inhibited biofilm formation and disrupted established biofilms in a concentration-dependent manner, without affecting bacterial growth. Furthermore, D-histidine downregulated the expression of virulence factors by inhibiting quorum sensing (QS)-related genes. Notably, combining D-histidine with antibiotics, such as amoxicillin, minocycline, and metronidazole, synergistically enhanced biofilm eradication and enabled the use of lower antibiotic dosages. These findings support the further evaluation of D-histidine as a potential anti-biofilm agent in the treatment of periodontitis.IMPORTANCEThe increasing prevalence of antibiotic-resistant A. actinomycetemcomitans biofilms posed a significant challenge in periodontitis management. This study demonstrated that D-histidine effectively targeted A. actinomycetemcomitans biofilms by disrupting structural integrity and suppressing virulence gene expression, without exerting bactericidal effects that could promote resistance development. Notably, D-histidine showed potent synergy with minocycline, significantly enhancing biofilm eradication while potentially enabling reduced antibiotic dosages. These findings established D-histidine as a promising adjunctive therapeutic agent, addressing the urgent need for novel approaches to overcome biofilm-associated antibiotic tolerance in periodontal treatment.

RevDate: 2025-09-29
CmpDate: 2025-09-29

Adhikari S, Khanal S, Marasini A, et al (2025)

Antimicrobial resistance and biofilm-forming ability in Staphylococcus aureus causing clinical bovine mastitis in Chitwan, Nepal.

Veterinary and animal science, 30:100508.

This cross-sectional study, conducted from August to December 2024, investigated the antimicrobial resistance and biofilm-forming abilities of Staphylococcus aureus from clinical bovine mastitis in Chitwan, Nepal. Out of 134 California Mastitis Test-positive milk samples, 32 (23.9%) were confirmed as S. aureus by biochemical tests and species-specific nuc gene PCR. Antimicrobial susceptibility testing of the 32 isolates against 12 antibiotics revealed high resistance rates, particularly to ampicillin (78.1%), nalidixic acid (75.0%), and enrofloxacin (62.5%). The prevalence of multidrug resistance (MDR), defined as resistance to ≥3 antibiotic classes, was alarmingly high, with 27 (84.4%) isolates classified as MDR. Presumptive methicillin-resistant S. aureus (MRSA), detected via cefoxitin resistance, was identified in 14 (43.8%) isolates, all of which were also MDR. Biofilm-forming abilities were assessed qualitatively and quantitatively, with 5 (15.6%) isolates classified as strong biofilm producers. Fisher's exact test revealed no significant association between biofilm formation and overall MDR status (p > 0.05). However, a statistically significant correlation was found between strong biofilm formation and high-level MDR (resistance to ≥ 4 classes) (p < 0.05), as well as between strong biofilm formation and presumptive MRSA status (p < 0.01). These findings highlight the co-existence of high-level resistance and strong virulence phenotypes in S. aureus from bovine mastitis in Nepal, underscoring the urgent need for robust antimicrobial stewardship, enhanced surveillance, and the development of strategies to mitigate biofilm-associated treatment failures.

RevDate: 2025-09-28
CmpDate: 2025-09-28

Kim MJ, Kim E, Mangal U, et al (2025)

Biofilm-resistant zwitterionic resin-based adhesive for orthodontic bracket-tooth interfaces: an in vitro evaluation.

Clinical oral investigations, 29(10):478.

OBJECTIVES: An in vitro study to verify the potential effectiveness of an orthodontic adhesive incorporating a polybetaine zwitterionic mixture in preventing biofilm formation.

MATERIALS AND METHODS: 2-methacryloyloxyethyl phosphorylcholine (MPC) and sulfobetaine methacrylate (SBMA), were added to An adhesive at 1 wt% (MS1) And 3 wt% (MS3). The MS0 group had no zwitterions. Flowability measurement, shear bond strength (SBS), the adhesive remnant index (ARI), and the contact angle were assessed. Bracket bonding was performed, and cross-sections were examined using scanning electron microscopy (SEM). Biofilm formation was analyzed using confocal laser scanning microscopy. Statistical analyses were conducted using R software. Wilcoxon tests with the Holm correction were used for non-parametric data, and pairwise t-tests with the Bonferroni correction were used for parametric data. Significance was set at P < 0.0001.

RESULTS: Flow analysis showed no significant differences in the experimental groups compared to the MS0 group (P > 0.05). The SEM images confirmed uniform bonding in all groups. SBS decreased significantly with higher MS content (P < 0.0001), And ARI scores shifted with the addition of zwitterionic mixtures, increasing scores to 1 And 2. MS3 showed a significantly lower contact angle compared to MS0 (P < 0.05). MS3 exhibited reduced biofilm formation and lower fluorescence intensity (P < 0.05).

CONCLUSIONS: Despite reductions in SBS, all adhesives remained at minimum acceptable levels. The 3 wt% zwitterionic adhesive effectively suppressed biofilm formation and may help prevent demineralization.

CLINICAL RELEVANCE: An orthodontic adhesive containing a zwitterionic mixture can satisfy clinical properties and prevent side effects due to biofilm formation.

RevDate: 2025-09-28
CmpDate: 2025-09-28

Shin J, Park DH, Jun W, et al (2025)

Optimization of the Purification Process for Lactiplantibacillus plantarum Lipoteichoic Acid with Anti-Biofilm Properties against Dental Pathogens.

Journal of microbiology and biotechnology, 35:e2506045 pii:jmb.2506.06045.

Biofilms formed by oral pathogens play a critical role in the initiation and development of various dental diseases by enhancing resistance to dental medicaments. Previously, we reported the potent anti-biofilm activity of Lactobacillus lipoteichoic acid (LTA), a major cell wall component of Gram-positive bacteria, against various dental pathogens. Nevertheless, the practical application of LTA as an anti-biofilm agent is limited due to its complex, cost- and labor-intensive purification processes. Therefore, to minimize the purification processes required to obtain LTA with anti-biofilm activity, we isolated LTA from Lactiplantibacillus plantarum (Lp.LTA) and its intermediates following each purification step, and compared their anti-biofilm activity against dental pathogens. The Lp.LTA intermediates underwent sequential purification after butanol extraction and hydrophobic-interaction chromatography, and these were designated as LTA-Butanol and LTA-HIC, respectively. The results of Western blot analysis demonstrated that LTA-HIC has a higher concentration of LTA than LTA-Butanol. Although both LTA-Butanol and LTA-HIC dose-dependently inhibited Streptococcus mutans and Porphyromonas gingivalis biofilm formation, the anti-biofilm activity of LTA-HIC was superior to that of LTA-Butanol and comparable to Lp.LTA. Furthermore, sodium hydroxide treatment of LTA-HIC diminished its anti-biofilm activity, suggesting that LTA is a key component responsible for the anti-biofilm capacity of LTA-HIC. Collectively, these results demonstrated that LTA-HIC serves as an intermediate in the LTA purification, retaining its anti-biofilm properties and offering a viable solution to the challenges associated with the LTA purification process.

RevDate: 2025-09-28

Song Y, Zhang X, Kong Z, et al (2025)

Enhancing the productivity of caproic acid in open culture chain elongation: A comparative study of biofilm systems.

Journal of environmental management, 394:127395 pii:S0301-4797(25)03371-7 [Epub ahead of print].

Growing global energy consumption and climate challenges have emphasized the need for biotechnology-based methods to synthesize valuable chemicals. Biological chain elongation (CE) shows great potential for decarbonization by producing valuable biochemicals - specifically medium-chain fatty acids (MCFAs) - from waste streams containing simple short-chain chemical building blocks like acetic acid and ethanol. However, one of the key parameters that impacts the commercial viability of CE, hence its integration in sustainable chemical manufacturing, is the volumetric productivity. In this study, we compared two biofilm systems using commercially available carriers (respectively AnoxK™ Z-200 and K5) with a planktonic system to examine how biofilms enhance the conversion of acetate and ethanol to caproic acid (a medium chain carboxylic acid). The results show that the Z-200 and K5 systems achieved productivity up to 3.46 ± 0.08 g caproate/L/d and 8.1 ± 0.8 g caproate/L/d, respectively, outperforming the planktonic system at 3.02 ± 0.12 g caproate/L/d. Cycle studies further proved the superior performance of the biofilm systems, as shown by short lag-time and fast reaction kinetics. We validated biofilm formation in the CE process through microscopic visualization using scanning electron microscopy (SEM), confocal laser scan microscopy (CLSM), biomass quantification, and analysis of extracellular polymeric substances (EPS). Analysis of the microbial community through 16S rRNA gene sequencing revealed that the biofilm systems were enriched by functional microbes (including Clostridium sensu stricto 12, Bacteroides, Lachnoclostridium, Caproiciproducens, and Proteiniphilum) previously associated with chain elongation microbiomes. The superior performance in the biofilm systems likely stems from improved biomass concentration, enriched functional microbes, and increased EPS production favouring retention of functional taxa. Overall, this work demonstrates how microbial biofilms can improve productivity of MCFA in CE systems, potentially expanding CE applications and improve decarbonization potential.

RevDate: 2025-09-28

Zhang Y, Huang C, Qiu Y, et al (2025)

Synergistic elimination of bacillus Calmette-Guérin biofilm and tissue restoration facilitated by ultrasound-mediated nanoparticles and antioxidants.

International immunopharmacology, 166:115582 pii:S1567-5769(25)01573-5 [Epub ahead of print].

Biofilm formation in Mycobacterium tuberculosis (MTB) enhances antibiotic resistance by impeding drug penetration and evading host immunity. This poses a significant challenge to conventional drug therapies, highlighting the urgent need for novel treatment strategies to overcome MTB's biofilm-mediated resistance. This study introduces the development of low-intensity ultrasound-mediated levofloxacin (LEV) and catalase (CAT) -loaded PEG-PLGA nanoparticles (LEV@CAT-NPs) for antimicrobial sonodynamic therapy (aSDT), offering an innovative strategy to combat BCG biofilm infection, by utilizing BCG as a model for MTB. N-acetylcysteine (NAC) was supplemented during the latter stages of the treatment process of anti-infection therapy to facilitate the transformation of macrophages to the M2 phenotype and to promote tissue repair. Ultrasound-mediated LEV@CAT-NPs, along with the subsequent addition of NAC not only enhanced repair at the infection site but also led to a progressive resolution of the inflammatory response in tissues. The treatment regimen induced a shift in macrophage polarization towards the M2 phenotype and modulated cytokine expression, decreasing pro-inflammatory while increasing anti-inflammatory cytokines, which contributed to the restoration of redox balance in the infected tissues. This study proposes a novel therapeutic strategy that not only targets drug-resistant MTB but also promotes tissue repair, highlighting its dual role in infection management.

RevDate: 2025-09-28
CmpDate: 2025-09-28

Setiawan M, Gaffar M, Wartati S, et al (2025)

Correlation of bacterial biofilm profile based on optical density cut-off with clinical severity in patients with chronic suppurative otitis media tubotympanic type.

The Medical journal of Malaysia, 80(5):537-543.

INTRODUCTION: Chronic suppurative otitis media (CSOM) is a middle ear infection with a high incidence in ear cases, is often recurrent, and causes hearing impairment. Bacteria in the CSOM frequently form biofilms, which enhance antibiotic resistance and contribute to disease progression. The aim of this study was to determine the correlation of bacterial biofilm profiles based on optical density cut-off with the clinical picture of patients with tubotympanic type CSOM.

MATERIALS AND METHODS: This was a cross-sectional study using a descriptive analytical design. The study was conducted at the tertiary teaching hospital of Hasanuddin University and the network hospital in Makassar, Indonesia, from July 2023 to July 2024. The study population consisted of patients with the CSOM tubotympanic type who met the inclusion criteria. Bacterial cultures and biofilm examinations were performed using the tissue culture plate method. Data were analyzed using SPSS® version 28.

RESULTS: A total of 53 patients with the CSOM tubotympanic type were included in this study. The mean age of the patients was 30±14 years. Pseudomonas aeruginosa was the most dominant bacterium (32.1%), with 20 other bacteria, and all these bacteria formed biofilms with either weak or moderate strength. There was a significant association between biofilm formation and nature of secretion (r=0.395, p=0.003). The chronicity of the disease (r=0.407, p=0.002) and the degree of hearing impairment (r=0.294, p=0.032) were also significant. A significant positive association was found between total clinical score and biofilm formation (r=0.429, p=0.001).

CONCLUSION: All bacteria found in the tubotympanic CSOM formed biofilms. The correlation analysis revealed a significant positive relationship between several clinical variables and biofilm formation. The substantial formation of biofilms may account for the fact that patients with elevated scores frequently experience infections that are challenging to manage with conventional antibiotic treatments.

RevDate: 2025-09-27

Wang J, Zhu W, Zhang X, et al (2025)

Charge-specific impacts of polystyrene nanoplastics on acidogenesis and biofilm adaptation in Ethanoligenens harbinense.

Bioresource technology pii:S0960-8524(25)01356-2 [Epub ahead of print].

Despite increasing awareness of the risks posed by nanoplastics (NPs) to environmental microbes, the charge-specific effects of functionalized NPs on anaerobic acidogenic bacteria remain poorly understood. This study investigated the impact of functionalized polystyrene (PS) NPs on Ethanoligenens harbinense, a model hydrogen-producing anaerobe. The growth, metabolic, and transcriptomic responses of this bacterium to non-functionalized (PS-NPs), amino-modified (PS-NH2), and carboxyl-modified (PS-COOH) variants were examined. Compared with the control group without NPs addition, PS-NH2 exerted the strongest inhibition, reducing hydrogen and ethanol production by 16% and 20%, respectively, while elevating reactive oxygen species (ROS) level by 148%. It also decreased biomass and down-regulated the expression of ribosome- and translation-related genes. In parallel, biofilm adaptation resulted in an 12% increase in polysaccharide. PS-COOH enhanced biofilm reinforcement with a 21% increase in polysaccharides and up-regulation of bapA and membrane transporter-related genes. Overall, PS-NH2 induced broad transcriptional changes, particularly in pathways related to the phosphotransferase system (PTS), ATP-binding cassette (ABC) transporters, genetic information processing, and signaling/regulatory systems in E. harbinense. These findings provide new insights into how surface charge modifications of NPs affect anaerobic bacterial metabolism and underscore their potential environmental risks.

RevDate: 2025-09-27

Sun H, Li W, Zhang S, et al (2025)

Differential profiles of antibiotic resistance genes in activated sludge and biofilm in wastewater treatment plants.

Journal of hazardous materials, 498:139955 pii:S0304-3894(25)02874-2 [Epub ahead of print].

Wastewater treatment plants (WWTPs) serve as significant sources of antibiotic resistance genes (ARGs) in natural water bodies, with activated sludge and biofilm being the two most critical biological treatment processes in WWTPs. A systematic comparison of ARG composition in these two processes is essential for optimizing the design and operation of wastewater treatment systems. This study collected samples from 16 WWTPs, including one year of longitudinal monitoring data from a full-scale facility and encompassing five biofilm types. The high-throughput sequencing results revealed that the relative abundance of ARGs in activated sludge was significantly higher than in biofilms, with average relative abundances of 2075.05 ppm and 1288.78 ppm, respectively. We also identified plasmids and microbial community structure as key factors contributing to the differences in ARG composition between activated sludge and biofilm. Plasmids primarily influenced the ARGs associated with enzymatic modification mechanisms, while the microbial community structure mainly impacted the abundance of ARGs, particularly through its effect on Bacteroidia. This structural influence was particularly pronounced on ARGs related to enzymatic inactivation, enzymatic modification, efflux pumps, target modification, and target protection mechanisms. These findings provide valuable insights for improving the management of ARGs in WWTPs and contribute to the development of strategies for mitigating ARG proliferation in wastewater treatment systems.

RevDate: 2025-09-27

Zhu B, Pan X, Guo H, et al (2025)

'Inner membrane - outer gel' PEDOT:PSS/MXene composite material enhances the extracellular electron transfer process by promoting biofilm growth.

Biosensors & bioelectronics, 291:118021 pii:S0956-5663(25)00897-8 [Epub ahead of print].

Against the backdrop of surging global energy demand, microbial fuel cells (MFCs) have garnered significant attention for their potential in green energy conversion. To solve the problem of low efficiency of long-distance electron transfer by microorganisms at the anode interface of MFCs, we propose a novel 'inner membrane - outer gel' PEDOT:PSS/MXene dual-phase hydrogel electrode. The electrode is fabricated via electrochemical polymerization, which further enables it to use a flexible heterogeneous interface to promote three-dimensional (3D) biofilm generation. Experimental results indicate that the composite anode exhibits a charge transfer resistance (Rct) as low as 4.71 Ω, with a maximum power density of 4.55 ± 0.17 W m[-2], which is 1.8 times the maximum power density of a pure hydrogel (only PEDOT:PSS hydrogel). Furthermore, 16S rRNA sequencing revealed that the relative abundance of Geobacter increased to 62.22 %, indicating a significant enrichment of electrogenic microorganisms. Molecular docking simulations further elucidated the electrostatic complementarity and hydrogen bonding interactions between PEDOT and the OmcZ protein, providing theoretical support for efficient electron transfer between conductive nanowires and electrodes within biofilms. Overall, this study provides both experimental and theoretical evidence for the feasibility of the 'inner membrane - outer gel' electrode in enhancing MFC performance, offering new insights into the design of high-performance conductive bioelectrodes in microbial energy conversion devices.

RevDate: 2025-09-27
CmpDate: 2025-09-27

do Nascimento JL, da Costa MCV, de Macêdo LF, et al (2025)

Laponite[®]-Based Smart Hydrogels for Sustained Topical Delivery of Silver Sulfadiazine: A Strategy for the Treatment of Contaminated or Biofilm-Forming Wounds.

Pharmaceutics, 17(9): pii:pharmaceutics17091234.

Background/Objectives: Silver sulfadiazine (AgSD) is widely used in the topical treatment of burns and infected wounds, but its conventional formulations present drawbacks such as poor water solubility, the need for multiple daily applications, and patient discomfort. To overcome these limitations, this study aimed to develop and evaluate Laponite[®] (LAP)-based hydrogels loaded with AgSD for controlled release and enhanced antimicrobial and antibiofilm efficacy, offering a promising alternative for the treatment of contaminated or biofilm-forming wounds. Methods: Laponite[®]-based hydrogels containing 1% and 1.2% AgSD (LAP@AgSD) were prepared using a one-pot method. The formulations were characterized rheologically, thermally, and structurally. In vitro drug release was assessed using Franz diffusion cells, and mathematical modeling was applied to determine release kinetics. Antibacterial and antibiofilm activities were evaluated against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa using standardized microbiological methods. Results: LAP@AgSD hydrogels exhibited pseudoplastic behavior, high structural integrity, and enhanced thermal stability. In vitro release assays revealed a sustained release profile, best fitted by the Weibull model, indicating diffusion-controlled mechanisms. Antibacterial assays demonstrated concentration-dependent activity, with LAP@AgSD 1.2% showing superior efficacy over LAP@AgSD 1% and comparable performance to the commercial silver sulfadiazine cream (CC-AgSD). Biofilm inhibition was significant for all formulations, with CC-AgSD 1% exhibiting the highest immediate activity, while LAP@AgSD 1.2% provided sustained antibiofilm potential. Conclusions: LAP-based hydrogels are promising smart delivery systems for AgSD, combining mechanical robustness, controlled drug release, and effective antibacterial and antibiofilm activities. These findings support their potential use in topical therapies for infected and chronic wounds, particularly where biofilm formation is a challenge.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Liang TT, Wen JQ, Chen GP, et al (2025)

Identification and Validation of Promising Targets and Inhibitors of Biofilm Formation in Pseudomonas aeruginosa: Bioinformatics, Virtual Screening, and Biological Evaluation.

Pathogens (Basel, Switzerland), 14(9): pii:pathogens14090855.

Pseudomonas aeruginosa, a member of the "ESKAPE" group of bacterial pathogens, exhibits biofilm-forming capacity, a key factor contributing to its resistance to conventional antibiotics and posing significant challenges in clinical treatment. To develop more effective therapeutics against such infections, identifying potential drug targets through bioinformatics analysis is essential. Consequently, we utilized data from the GEO database to investigate differentially expressed genes between planktonic and biofilm groups, and identified drug targets through the construction of a protein-protein interaction (PPI) network and the cytoHubba algorithm. Inhibitors targeting this protein were identified through molecular docking screening of the FDA-approved drug library, and their anti-biofilm activity was validated in vitro. Through bioinformatics analysis, we identified GacS as the drug target in this study for treating biofilm-related infections. Virtual screening revealed that oxidized glutathione (GSSG) and arformoterol tartrate (ARF) are both capable of tightly binding to GacS and demonstrating good stability. In vitro experiments further confirmed that both GSSG and ARF demonstrated anti-biofilm activity, particularly when combined with azithromycin (AZM) or clarithromycin (CAM), significantly enhancing the biofilm inhibition effects of these antibiotics. This combination therapy offers a new and innovative strategy to combat biofilm-associated infections, showcasing the potential of GacS inhibitors in clinical applications. In conclusion, GSSG and ARF may serve as effective GacS inhibitors, and their combination with AZM or CAM could provide a novel approach for treating biofilm-related infections, paving the way for more effective treatment options.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Bridi V, do Prado DPG, Ferreira SRR, et al (2025)

Antimicrobial Resistance and Biofilm Formation in Bacterial Species Isolated from a Veterinary Hospital.

Pathogens (Basel, Switzerland), 14(9): pii:pathogens14090845.

Micro-organisms are abundant in nature and can also be found in hospital settings, causing high rates of infections. This study aimed to identify bacteria isolated from a veterinary hospital, as well as to perform antimicrobial susceptibility testing using the disk diffusion method (Kirby-Bauer), biofilm production tests using 96-well polystyrene microtiter plates and crystal violet dye, and genetic analysis of the ica operon of Staphylococcus isolates. Three collections were made from eleven surfaces and objects in the hospital's non-critical areas (general areas) and critical areas (surgical center), totaling thirty-three samples. A total of 66 different bacterial isolates were obtained, with 77% (51/66) Gram-positive and 23% (29/66) Gram-negative. Resistance profiles were found for multidrug-resistance (MDR), methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE), and other unidentified species of methicillin-resistant coagulase-negative (MRCNS) and extended-spectrum beta-lactamase (ESBL), as well as biofilm production rates of 57% (38/66) of the isolates. Analysis of the operon genes for Staphylococcus sp. showed divergence in some samples when compared to the phenotypic test performed. In summary, there is a high presence of micro-organisms with resistance and virulence factors spread throughout the various areas of the veterinary hospital.

RevDate: 2025-09-27
CmpDate: 2025-09-27

De Plano LM, Iaconis A, Papasergi S, et al (2025)

Role of NaCl and Glutamine on Biofilm Production from Pseudomonas aeruginosa.

Microorganisms, 13(9): pii:microorganisms13092198.

Pseudomonas aeruginosa is an opportunistic pathogen capable of forming antibiotic-resistant biofilms, contributing to persistent infections and treatment failure. Environmental factors such as osmolarity and nutrient availability are known to influence biofilm formation and virulence. In this study, we investigated the effects of NaCl depletion and glutamine supplementation on biofilm production in three P. aeruginosa strains: the laboratory strain ATCC 27853 and two clinical isolates with distinct antibiotic resistance profiles and phenazine production patterns (P. aeruginosa Pr, pyorubrin-producing, and P. aeruginosa Pc, pyocyanin-producing). Bacteria were cultured in standard Luria-Bertani (LB) medium, LB without NaCl, and LB in which yeast extract was replaced by glutamine. For each strain and condition, we assessed growth kinetics, phenazine production, and biofilm formation. Biofilm development was quantified via XTT assays and compared to secondary metabolite profiles. NaCl removal did not substantially affect growth, whereas glutamine supplementation reduced growth, especially in the laboratory strain. Both conditions modulated secondary metabolite production and biofilm formation in a strain-specific manner. In P. aeruginosa ATCC 27853, NaCl depletion significantly increased pyoverdine, pyocyanin, and QS gene expression, while biofilm formation showed significant differences only at 72 h; in contrast, glutamine supplementation affected only pyoverdine. A similar trend was observed in the clinical strain P. aeruginosa Pc, although NaCl depletion did not significantly impact pyoverdine production but already enhanced biofilm formation at 48 h. In P. aeruginosa Pr, only glutamine appeared to alter the considered parameters, increasing pyoverdine production while reducing pyocyanin and biofilm levels, although the absence of NaCl also negatively impacted biofilm formation. These findings highlight the impact of osmotic and nutritional signals on P. aeruginosa virulence traits.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Shen J, Li Y, H Miao (2025)

The PP2A Catalytic Subunit PPH21 Regulates Biofilm Formation and Drug Resistance of Candida albicans.

Microorganisms, 13(9): pii:microorganisms13092093.

Candida albicans (C. albicans) biofilms exhibit enhanced resistance to conventional antifungal agents; however, the underlying pathogenic mechanisms warrant deeper exploration. Protein phosphatase 2A (PP2A), especially its catalytic activity, is crucial for maintaining physiological balance. This study focused on the role of the PP2A catalytic subunit coding gene PPH21 in biofilm formation and drug resistance of C. albicans. The mutant strain (pph21Δ/Δ) was generated and identified. The oxidative stress was detected by the reactive oxygen species (ROS) and mitochondrial membrane potential (MMP). The autophagic activity was evaluated, and the autophagosomes were observed by transmission electron microscopy (TEM). The biofilm formation was measured by XTT reduction assay, crystal violet (CV) staining, and scanning electron microscopy (SEM). The susceptibility to antifungal agents was examined by XTT reduction assay and spot assay. Additionally, the antioxidant N-acetylcysteine (NAC) was applied to clarify the regulatory effect of C. albicans autophagy on oxidative stress. The pathogenicity of PPH21 in oral C. albicans infection was evaluated through in vivo experiments. We found that PPH21 deletion led to increased oxidative stress and autophagic activities, but it can be reversed by the application of NAC. Moreover, PPH21 deletion also impaired the biofilm formation ability and reduced resistance to antifungal agents. Our findings revealed that PPH21 is involved in both virulence and stress adaptation of C. albicans.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Jotic A, Cirkovic I, Bozic D, et al (2025)

Antibiofilm Effects of N-Acetyl Cysteine on Staphylococcal Biofilm in Patients with Chronic Rhinosinusitis.

Microorganisms, 13(9): pii:microorganisms13092050.

Staphylococcal bacterial biofilm plays an important role in the pathogenesis and bacterial persistence of chronic rhinosinusitis. N-acetyl cysteine (NAC) has an inhibitory role in biofilm formation, suppressing adhesion and matrix production or favoring dispersal of preformed biofilm. The aim of this study was to examine the in vitro effect of NAC on Staphylococcal biofilm formation by bacterial strains isolated from tissue samples of patients with chronic rhinosinusitis with or without nasal polyps (CRSwNP and CRSsNP). Prospective study included 75 patients with CRS. The biofilm-forming capacity of isolated strains was detected by microtiter-plate method and the effects of sub-inhibitory (1/2x, 1/4x, and 1/8x minimal inhibitory concentration, MIC) and supra-inhibitory minimal concentrations (2x, 4x, and 8xMIC) of NAC on biofilm production were investigated. Staphylococcal bacterial strains were isolated in 54 (72%) patients, and the most frequently isolated species were Staphylococcus aureus (40.7%). Coagulase-negative Staphylococci species were weak producers of biofilm, while S. aureus was a strong biofilm producer. Concentration of 3.1 mg/mL (1/2 MIC) was sufficient to completely prevent biofilm formation in 77.8% of the isolates, where 49.6 mg/mL (8xMIC) led to the complete eradication of formed biofilm in 81.5% of the isolates. The subinhibitory and eradication effects were dose- and strain-dependent. There were no significant differences in MIC values between isolates from patients with CRSwNP and CRSsNP isolates. NAC proved to be effective in inhibiting biofilm formation and reducing formed biofilm by Staphylococcal isolates from patients with CRS. A comparable antibiofilm effect was exhibited in both phenotypes of CRS, indicating that NAC's antibiofilm activity was independent of the underlying clinical phenotype, and more targeted on biofilm matrix components.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Hessling M, Meulebroeck W, B Alsanius (2025)

A Collection and Analysis of Simplified Data for a Better Understanding of the Complex Process of Biofilm Inactivation by Ultraviolet and Visible Irradiation.

Microorganisms, 13(9): pii:microorganisms13092048.

Biofilms are communities of microorganisms that pose a problem in many areas, including the food industry, drinking water treatment, and medicine, because they can contain pathogens and are difficult to eliminate. For this reason, the possibility of biofilm reduction by ultraviolet (UV) or visible light was investigated using data from published reports. Results for different applications, spectral ranges, and microorganisms were compared by performing MANOVA tests. Approximately 140 publications were found that dealt with the irradiation of water or surfaces for biofilm reduction or reduction in biofilm formation. Irradiation of surfaces with UV or visible light in the spectral range 200-525 nm had a positive effect on biofilm reduction and reduction in biofilm formation, although the results for irradiation of water were conflicting. Most investigations were carried out on P. aeruginosa biofilms, but other Gram-positive and Gram-negative bacteria, as well as some fungi and their biofilm sensitivities to irradiation, were also analyzed. Limited data were available for the UVB (280-315 nm) and UVA (315-400 nm) range. Most experiments to date have been carried out in the UVC (100-280 nm) or in the visible violet/blue spectral (400-500 nm) range, with the UVC range being 2-3 orders of magnitude more efficient in terms of applied irradiation dose. Other quantitative statements were difficult to make as the results from the different working groups were highly scattered. Irradiation can reduce the microorganisms in biofilms but does not completely remove biofilms. New biofilm formation can at least be delayed by surface irradiation. Whether it is also possible to prevent the formation of new biofilms in the long term is open to question. Which irradiation wavelengths are optimal for anti-biofilm measures is also still unclear.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Furnica DT, Falkenstein J, Dittmer S, et al (2025)

Human-like Biofilm Models to Study the Activity of Antifungals Against Aspergillus fumigatus.

Microorganisms, 13(9): pii:microorganisms13092040.

Aspergillus fumigatus is an opportunistic filamentous fungus that primarily affects the respiratory tract of the human body. Depending on its host's immune response, the pathogen can cause invasive pulmonary aspergillosis (IPA). Biofilm formation by A. fumigatus increases virulence and resistance against antifungals and immune response and is one important factor in IPA development. Here, two human-like models, precision cut lung slices (PCLS) and a biofilm co-culture model, have been developed to test the anti-biofilm activity of voriconazole, amphotericin B, as well as luliconazole against A. fumigatus. In both assays, metabolically active A. fumigatus biofilms were examined at different biofilm developmental stages using an XTT assay. A decrease in the metabolic activity of the fungal biofilms was detected for each of the tested agents in both assays. Significant anti-biofilm effects exist against early-stage biofilm in the co-culture model. In the PCLS assay, amphotericin B showed the strongest inhibition after 24 h. In conclusion, the applied PCLS ex vivo model can be used to study the property and activity of certain antifungal compounds against Aspergillus biofilm. With its close resemblance to human conditions, the PCLS model has the potential for improving the current understanding of biofilm treatments in laboratory settings.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Risheq S, Sancho A, Friedman M, et al (2025)

Ciprofloxacin-Coated Tympanostomy Tubes with Sustained-Release Varnish: A Novel Strategy to Combat Biofilm Formation by Pseudomonas aeruginosa.

Microorganisms, 13(9): pii:microorganisms13092039.

OBJECTIVE: The aim of this study is to develop and evaluate the antibacterial and anti-biofilm efficacy of ciprofloxacin-coated tympanostomy tubes (TTs) using a sustained-release varnish (SRV-CIPRO) and introduce a novel tympanic membrane model for preclinical evaluation.

STUDY DESIGN: This was an in vitro experimental study.

SETTING: This study was conducted in a biofilm research laboratory in an academic medical center.

METHODS: Sterile fluoroplastic TTs were coated with SRV-CIPRO or placebo varnish. A novel tympanic membrane (TM) model was developed using a layered agar-plastic system. Antibacterial activity, biofilm inhibition, and bacterial viability were assessed through agar diffusion, MTT, ATP quantification, HR-SEM, and SD-CLSM.

RESULTS: SRV-CIPRO-coated TTs exhibited sustained antibacterial activity for up to 10 days. Compared to the placebo, SRV-CIPRO significantly inhibited biofilm formation, reduced metabolic activity, and decreased bacterial viability (p < 0.05). Imaging confirmed fewer bacterial colonies on SRV-CIPRO TTs. The TM model allowed realistic testing of tube insertion and infection simulation.

CONCLUSION: SRV-CIPRO-coated TTs offer sustained antibiotic delivery, potentially reducing postoperative otorrhea and biofilm-related complications. The TM model provides a platform for preclinical evaluation of middle ear devices.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Maravić-Vlahoviček G, Kindl M, Andričević K, et al (2025)

Modulatory Effects of Satureja montana L. Essential Oil on Biofilm Formation and Virulence Factors of Pseudomonas aeruginosa.

Pharmaceuticals (Basel, Switzerland), 18(9): pii:ph18091269.

Background: Antimicrobial resistance is a major global health threat, particularly from pathogens such as Pseudomonas aeruginosa, known for forming biofilms and producing virulence factors that cause persistent infections. Essential oils (EOs) offer promising alternatives to conventional antimicrobial therapy due to their antimicrobial and antibiofilm properties. This study aimed to investigate the modulatory effects of a thymol-rich EO from Satureja montana L. on planktonic growth, biofilm formation, swarming motility, proteolytic activity and pyocyanin production of P. aeruginosa PAO1. Methods: The essential oil, isolated by hydrodistillation from S. montana aerial parts, was analysed by GC-MS. The minimum inhibitory concentration (MIC) of the EO and thymol was determined using the broth microdilution method. Sub-MICs were tested for planktonic growth and biofilm formation. Virulence was assessed by testing swarming motility, proteolytic activity and pyocyanin production. Results: The EO was characterised by a very high content of monoterpenes, with thymol dominating (56.47%). MIC for both EO and thymol was 4 mg/mL. They showed a biphasic effect: higher concentrations significantly inhibited planktonic growth (36-58% reduction; p < 0.05), while lower concentrations promoted it (10-17% increase; p < 0.05). Biofilm biomass varied, but the biofilm index indicated promotion at higher concentrations (0.125-0.5 mg/mL; p < 0.05). Both inhibited swarming at 0.5 mg/mL (thymol was more effective). Thymol decreased proteolytic activity, while EO increased pyocyanin production. Conclusions: S. montana essential oil and thymol show concentration-dependent modulation of P. aeruginosa growth, biofilms and virulence, suggesting their potential as anti-virulence agents, although the biphasic responses require careful dosing.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Elhawary EA, Soltane R, Moustafa MH, et al (2025)

Sustainable MnO2/MgO Bimetallic Nanoparticles Capped with Sword Fern Methanol Extract Attain Antioxidant/Anti-Biofilm Potential: A UPLC-ESI/LC/MS and Network Pharmacology-Supported Study.

Pharmaceuticals (Basel, Switzerland), 18(9): pii:ph18091262.

Background: Nephrolepis exaltata (sword fern) possesses a considerable amount of phytochemicals and different biological activities. The current study investigates the anti-biofilm potential of greenly synthesized bimetallic nanoparticles of Nephrolepis exaltata leaf methanol extract (NEME-MnO2-MgO BNPs). Methods: The NEME was subjected to UPLC/MS analysis, followed by characterization of its NPs by size, zeta potential, FTIR, entrapment efficiency, and release. Then, antioxidant, antimicrobial and antibiofilm assays were employed, followed by in silico studies. Results: The UPLC/MS analysis of NEME led to the tentative identification of 27 metabolites, mostly phenolics. The MnO2-MgO BNPs presented a uniform size and distribution and exhibited IC50 values of 350 and 215.6 μg/mL, in the DPPH and ABTS assays, respectively. Moreover, the NPs exhibited antimicrobial and anti-biofilm efficacies against Pseudomonas aeruginosa, Klebsiella pneumonia (ATCC-9633), Staphylococcus aureus (ATCC-6538), Escherichia coli, Bacillus cereus, and C. albicans, with MIC values of 250-500 μg/mL. The MnO2-MgO BNPs inhibited Candida albicans biofilms with a % inhibition of 66.83 ± 2.45% at 1/2 MIC. The network pharmacology highlighted epigallocatechin and hyperoside to be the major compounds responsible for the anti-biofilm potential. The ASKCOS facilitated the prediction of the redox transformations that occurred in the green synthesis, while the docking analysis revealed enhanced binding affinities of the oxidized forms of both compounds towards the outer membrane porin OprD of P. aeruginosa, with binding scores of -4.6547 and -5.7701 kcal/mol., respectively. Conclusions: The greenly synthesized Nephrolepis exaltata bimetallic nanoparticles may provide a promising, eco-friendly, and sustainable source for antimicrobial agents of natural origin with potential biofilm inhibition.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Jung EH, Hwang G, KR Kim (2025)

Effect of 6-Shogaol Derived from Ginger (Zingiber officinale) on Dual-Species Biofilm Formation by Streptococcus mutans and Candida albicans.

Nutrients, 17(18): pii:nu17182999.

BACKGROUND/OBJECTIVES: Dental plaque, a biofilm composed of accumulated oral microorganisms, is a key contributor to various oral diseases. 6-shogaol, a bioactive compound of ginger, is known to have pharmacological activities, including anticancer, anti-inflammatory, and antimicrobial activities. Therefore, we aimed to determine the effects of 6-shogaol on dual-species biofilms of Streptococcus mutans (S. mutans) and Candida albicans (C. albicans).

METHODS: Dual-species oral biofilms were formed on hydroxyapatite (HA) disks for 42 h and exposed to 6-shogaol. The pH was measured in the experimental medium, and the biomass, colony-forming unit (CFU) of microbial cells, and insoluble extracellular polysaccharides (EPS) were quantified in the biofilm formed on the HA disk. Confocal laser scanning microscopy (CLSM) was used to assess biofilm morphology, and quantitative polymerase chain reaction was performed to analyze gtf gene expression.

RESULTS: 6-shogaol dose-dependently reduced insoluble EPS, CFU counts, and dry weight of biofilms. The pH was maintained above 5.5 in the 6-shogaol-treated group. CLSM images showed that S. mutans proliferation, C. albicans hyphal development, and EPS production were markedly inhibited in biofilms treated with 6-shogaol. The expression of gtfB and gtfC was significantly downregulated by 6-shogaol.

CONCLUSIONS: These findings suggest that 6-shogaol has the potential to be a promising natural product for the prevention and management of oral biofilm-related oral diseases.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Murray RK, Martin AE, Zipkowitz S, et al (2025)

α-Amylase-Mediated Antibiotic Degradation and Sequestration in Pseudomonas aeruginosa Biofilm Therapy.

Antibiotics (Basel, Switzerland), 14(9): pii:antibiotics14090941.

BACKGROUND: As of 2022, 80% of all documented microbial infections are biofilm-associated: communities of microorganisms adhered to a surface and enclosed in a complex extracellular polymeric substance (EPS). The EPS acts as a physical barrier protecting the bacteria from antimicrobial agents and host immune responses. To combat this hurdle, the application of glycoside hydrolases (GH) has been investigated due to their ability to cleave particular structural polysaccharides within the EPS, thus breaking down the protective barrier and improving antibiotic clearance. While various studies demonstrate the capacity of GHs to improve antibiotic efficacy against biofilms in combination, there is clear differential success between these treatments depending on the GH and antibiotic chosen. Due to the overlap of GH targets and antibiotic structures, it is imperative to ensure that the antibiotics in combinatorial treatments are not degraded by the GH.

METHODS: This study aimed to screen the GH α-amylase produced from Aspergillus oryzae (AO) and Bacillus subtilis (BS), combined with various antibiotics from different classes, charges, and mode of actions by determining MICs. against the bacterium Pseudomonas aeruginosa (PA) of 6 antibiotics with or without α-amylase and treat 2-day PA biofilms with antibiotics with or without GHs. Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) stability assays and Differential Scanning Fluorimetry (DSF) were conducted to determine antibiotic and GH degradation as well as antibiotic sequestration.

RESULTS: Increased MICs in the presence of GHs as well as decreased antibiotic clearance against 2-day biofilms were suggestive of antibiotic degradation. LC-MS/MS stability assays of tetracycline and ciprofloxacin in the presence and absence of α-amylase further demonstrated the α-amylase-mediated antibiotic sequestration. Differential scanning fluorimetry (DSF) assays confirmed α-amylase-antibiotic interactions.

CONCLUSIONS: This study suggests that α-amylase is capable of degrading and sequestering a variety of antibiotics, and the degree to which these phenomena occur varies depending upon the source of the GH. As a potential treatment for biofilm-associated infections, it is imperative that the GH + antibiotic combinations are determined compatible prior to clinical use.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Oliveira MCF, Canellas ALB, Berbert LC, et al (2025)

Assessment of Antimicrobial Resistance and Virulence of Biofilm-Forming Uropathogenic Escherichia coli from Rio de Janeiro.

Antibiotics (Basel, Switzerland), 14(9): pii:antibiotics14090869.

Background/Objectives: Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections in both community and hospital settings worldwide. Antimicrobial-resistant UPEC strains pose a significant challenge for effective antibiotic therapy. In this study, 50 bacterial isolates recovered from urine samples of patients attended in different sectors of a public hospital in Rio de Janeiro over five months were analyzed to assess antimicrobial resistance and virulence profiles through broad gene screening. Methods: Biofilm production was assessed using a semi-quantitative adherence assay. PCR was employed to investigate 27 resistance genes, 6 virulence genes, sequence types (STs), and phylogroups. Susceptibility to 25 antimicrobial agents was determined by disk diffusion testing. Furthermore, the pathogenic potential was evaluated in vivo using the Tenebrio molitor larvae infection model. Results: Most UPEC isolates were moderate or strong biofilm producers (41/50; 82%). The sul1 and sul2 resistance genes were the most frequently detected (58%). Two virulence gene patterns were identified: fyuA, iutA, fimH, cnf1 and fyuA, iutA, fimH (13 isolates; 26%). ST131 and ST73 were the most common sequence types (16% each), and phylogroup B2 was the most prevalent (50%). Thirty isolates (60%) were multidrug-resistant, most of which belonged to phylogroup B2. UPEC exhibited dose-dependent lethality, causing 100% mortality at 2.6 × 10[8] CFU/mL within 24 h. Conclusions: These findings reinforce the urgent need for surveillance strategies and effective antimicrobial stewardship in clinical practice.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Oh Y, TJ Kim (2025)

Temperature Adaptive Biofilm Formation in Yersinia enterocolitica in Response to pYV Plasmid and Calcium.

Antibiotics (Basel, Switzerland), 14(9): pii:antibiotics14090857.

Background/Objectives: Yersinia enterocolitica is a pathogenic bacterium that forms biofilms, enhancing its persistence and resistance to antimicrobial agents. Biofilm formation in Y. enterocolitica is influenced by environmental factors such as temperature, calcium, and the presence of the virulence plasmid pYV. This study aims to explore how temperature, calcium, and pYV modulate biofilm formation in Y. enterocolitica, with a focus on motility and extracellular polymeric substance (EPS) production as key factors. Methods: Y. enterocolitica strains with and without the pYV plasmid were cultured at two different temperatures (26 °C and 37 °C). The effect of calcium (5 mM) on biofilm formation was tested at both temperatures. Biofilm formation was measured using crystal violet staining, motility was assessed using soft agar plates, and EPS production was quantified to determine its role in biofilm stabilization. Results: At 26 °C, biofilm formation increased in pYV-negative strains, driven primarily by motility and flagellar expression. In contrast, at 37 °C, pYV-positive strains showed strong biofilm formation despite reduced growth, with EPS production as the key stabilizing factor. Calcium modulated biofilm formation in a temperature-dependent manner: at 26 °C, 5 mM calcium modestly reduced biofilm formation in pYV-negative strains, while at 37 °C, it significantly suppressed both EPS production and biofilm formation by approximately 50% in pYV-positive strains. Conclusions: This study reveals a novel regulatory switch where temperature, calcium, and pYV modulate biofilm formation in Y. enterocolitica. These findings suggest that Y. enterocolitica can adapt between motility- and EPS-dominated biofilm strategies depending on environmental conditions. Understanding these mechanisms offers potential targets for controlling biofilm-related persistence in clinical and food safety contexts.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Tegegne DT, Abbott IJ, B Poźniak (2025)

Catheter-Associated Urinary Tract Infections: Understanding the Interplay Between Bacterial Biofilm and Antimicrobial Resistance.

International journal of molecular sciences, 26(18): pii:ijms26189193.

The increasing use of urinary catheters in healthcare, driven by an aging population and escalating antimicrobial resistance, presents both benefits and challenges. While they are essential to managing urinary retention and enabling precise urine output monitoring, their use significantly increases the risk of catheter-associated urinary tract infections (CAUTIs), the most common type of healthcare-associated infection. CAUTI risk is closely linked to the duration of catheterization and the formation of bacterial biofilms on catheter surfaces. These biofilms, often composed of polymicrobial communities encased in an extracellular matrix, promote persistent infections that are highly resistant to conventional antimicrobial therapies. Common CAUTI uropathogens include E. coli, E. faecalis, P. aeruginosa, P. mirabilis, K. pneumoniae, S. aureus, and Candida spp. The complexity and resilience of these biofilm-associated infections underscore the urgent need for innovative treatment strategies. Therefore, dynamic in vitro bladder infection models, which replicate physiological conditions such as urine flow and bladder voiding, have become valuable tools for studying microbial behavior, biofilm development, and therapeutic interventions under real clinical conditions. This review provides an overview of CAUTIs, explores the role of biofilms in sub-optimal responses to antimicrobial treatment and advances in model systems, and presents promising new approaches to combating these infections.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Liberatore A, Bertoldi A, Balboni A, et al (2025)

Biofilm Formation, c-di-GMP Production, and Antimicrobial Resistance in Staphylococcal Strains Isolated from Prosthetic Joint Infections: A Pilot Study in Total Hip and Knee Arthroplasty Patients.

International journal of molecular sciences, 26(18): pii:ijms26188929.

Total joint arthroplasty (TJA) and total joint replacement (TJR) are effective treatments for end-stage osteoarthritis, but prosthetic joint infections (PJIs) remain a significant complication. These infections are often associated with bacteria that form biofilms, which contribute to their persistence and resistance to treatment. The aim of this study was to investigate the biofilm-forming ability, cyclic diguanylic acid (c-di-GMP) production, and the presence of biofilm-associated genes in Staphylococcus aureus and coagulase-negative Staphylococci (CoNS) isolates obtained from synovial fluid samples of patients with PJIs following TJA and TJR. A total of 198 samples were analyzed, with bacterial growth detected in 33 samples (16.7%). Among these, 10 strains of S. aureus and 22 strains of CoNS were identified. Biofilm formation was evaluated using the crystal violet assay, and c-di-GMP levels were measured. A statistically significant linear regression was found between biofilm formation and c-di-GMP production (p = 0.016, R[2] = 0.18). Genetic analysis revealed the presence of biofilm-associated genes, including icaA, clfA, fnbA in S. aureus, and atlE, fbe in CoNS. Furthermore, there was a statistically significant difference in c-di-GMP production between strains harboring the icaA gene and strains without icaA (p = 0.016), while oxacillin resistance was detected more frequently in strains carrying fbe gene (p = 0.031). The study emphasizes the variability in antibiotic resistance profiles among staphylococcal isolates, underscoring the complexity of managing these infections.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Huang X, Yang H, Wang C, et al (2025)

Pterostilbene Eliminates MRSA Independent of Metabolic State and Effectively Prevents Biofilm Formation in Milk Matrices.

Foods (Basel, Switzerland), 14(18): pii:foods14183236.

The relentless spread of antimicrobial resistance poses a severe threat to global public health, food safety, and environmental security. Natural products with potent antimicrobial activity offer prospective substitutes for traditional antibiotics and chemical preservatives. Here, we demonstrate that pterostilbene (PT), a natural dietary compound, exhibits rapid lytic activity against methicillin-resistant Staphylococcus aureus (MRSA). PT displayed metabolism-independent bactericidal effects, effectively eradicating dormant persister cells within one hour, though its activity was partially attenuated under anaerobic conditions. Mechanistically, PT disrupted membrane integrity by increasing permeability, dissipating membrane potential, depleting cellular ATP, and suppressing reactive oxygen species (ROS) generation. Its efficacy was modulated by membrane phospholipid composition, with phosphatidylglycerol (PG) and cardiolipin (CL) critically influencing antimicrobial potency. Crucially, PT robustly inhibited MRSA biofilm formation in milk. These findings highlight PT's potential as a structurally stable, natural antimicrobial for controlling resilient MRSA, particularly against biofilm-associated and persister subpopulations in food systems.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Agboola OE, Agboola O, Ayinla ZA, et al (2025)

Integrated Virtual Screening for Anti-Caries Compounds from Neem: Dual-Target Inhibition of Biofilm Formation and Bacterial DNA Replication.

Biomedicines, 13(9): pii:biomedicines13092202.

Background: Dental caries arise from polymicrobial biofilms and require interventions that address both local virulence and systemic burden. Methods: A curated set of 124 neem-derived phytochemicals was screened against Streptococcus mutans glucansucrase (3AIC) and Staphylococcus aureus DNA gyrase B (3U2D) using harmonized AutoDock Vina parameters. Ligand standardization and receptor preparation followed conventional protocols. Results: The most favorable docking scores reached -10.7 kcal·mol[-1] for 3AIC and -8.9 kcal·mol[-1] for 3U2D. Redocking produced pose RMSD values of 1.52 Å (3AIC) and 0.96 Å (3U2D). Per-receptor ADMET profiles for the six top-ranked compounds indicated median logP values of 4.93 (3AIC) and 4.52 (3U2D), median TPSA values of 80.3 and 62.9 Å[2], median rotatable bonds of 2.5 and 1.0, and median QED values of 0.41 and 0.76, respectively. Conclusions: An integrated, dual-target screen prioritized neem constituents with plausible local anti-cariogenic activity and physicochemical features compatible with systemic disposition. These in silico findings motivate targeted experimental validation.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Ding X, An Q, Kang H, et al (2025)

Whole-Genome Analysis of a Novel Multidrug-Resistant Escherichia coli Strain from Dairy Calves in Northeast China: Mechanisms of Antibiotic Resistance and Biofilm Formation.

Biology, 14(9): pii:biology14091257.

The use of antibiotics is so widespread in animal husbandry, but negligent management and lack of policies often lead to the massive use of antibiotics on farms. In this study, we collected cases of epidemic calf diarrhea in northeastern China and isolated a new strain of multidrug-resistant Escherichia coli (MDR-E. coli). In order to explore the information of this pathogen in detail, we used whole-genome sequencing to determine the genome sequence, and explored in detail the resistance, pathogenicity, genetic evolution and other biological processes of the strain through bioinformatics analysis. The results showed that the E. coli isolated in this study was a new multidrug-resistant strain with a large number of drug resistance genes (77) and virulence genes (84), including a circular chromosome and five circular plasmids, which are basically impossible to treat by currently commonly used antibiotics. The findings of this study suggest that the prolonged misuse of antibiotics in agricultural settings may contribute to the development of antibiotic-resistant strains of E. coli. This, in turn, has the potential to trigger outbreaks of antibiotic-resistant bacterial diarrhea, leading to substantial economic losses and posing significant public health risks. These results underscore the necessity for the judicious use of antibiotics and will inform the development of pertinent policies and regulations.

RevDate: 2025-09-27
CmpDate: 2025-09-27

Oh JH, Kim E, M Cho (2025)

Biofilm Formation by Rice Rhizosphere Nitrogen-Fixing Microorganisms and Its Effect on Rice Growth Promotion.

Biology, 14(9): pii:biology14091249.

Excessive nitrogen fertilizer use contributes to environmental pollution and undermines agricultural sustainability. Enhancing symbiotic interactions between rice and nitrogen-fixing microorganisms offers a promising strategy to potentially improve nitrogen use efficiency (NUE). This study investigates the role of rice root exudates in promoting biofilm formation by nitrogen-fixing microbes to enhance nitrogen fixation. Nine nitrogen-fixing microbial strains were evaluated for biofilm formation in response to flavone and apigenin treatments, with Gluconacetobacter diazotrophicus KACC 12358 serving as the reference strain. The most responsive strain was selected, and a library of 1597 natural compounds was screened to identify those that promote biofilm formation in both the selected and reference strains. A. indigens KACC 11682 exhibited the highest biofilm-forming capacity, with apigenin treatment showing an OD595 value approximately 1.4 times higher than the DMSO control. Screening identified 68 compounds that enhanced biofilm formation by more than 500% compared to the control. Among them, eight compounds induced strong biofilm formation (O.D. > 2.0) in A. indigens. Cardamomin, a chalconoid flavonoid, emerged as one of the most effective compounds, showing a 245% increase in biofilm formation. Growth promotion assays showed that A. indigens increased rice fresh weight by approximately 128% compared to untreated controls. This study demonstrates the potential of rice root exudate-derived compounds to promote beneficial symbiosis with nitrogen-fixing microbes. These findings offer a novel approach that may contribute to enhancing rice NUE. Future research will focus on evaluating the long-term effects of these compounds and microorganisms, assessing their applicability in real agricultural settings, and conducting further validation across various rice cultivars.

RevDate: 2025-09-26

Russo S, Muscetta M, Liotta I, et al (2025)

Sunlight driven photo-treatment of polyhydroxybutyrate microplastics mediated by carbon nanodots-doped ZnO mesocrystals: Induced surface changes boost degradation in soil and biofilm formation.

Journal of hazardous materials, 498:139933 pii:S0304-3894(25)02852-3 [Epub ahead of print].

Plastics are widely used due to their versatility. However, their accumulation as microplastics and nanoplastics in the environment poses a significant threat for the ecosystems. Although biodegradable polymers, like polyhydroxybutyrate (PHB), offer a sustainable alternative, their degradation could still lead to fragmentation and MP accumulation, hence it is essential to enhance biodegradation rates in order to mitigate environmental impacts. This study investigates the integration of photocatalytic pretreatment with natural biodegradation to accelerate PHB biodegradation. Photoactive ZnO mesocrystals doped with biowaste-derived carbon nanodots, prepared via a wet-chemical approach, are proposed to improve the photocatalytic efficiency under sunlight. ZnO mesocrystals doped with 30 wt% of carbon nanodots exhibited superior photocatalytic properties, thus photodegrading PHB microplastics more efficiently than bare ZnO. Phototreated PHB microplastics exhibit an improved biodegradation in soil when exposed for a controlled irradiation time. Additionally, PHB microplastics photo-treated in the presence of doped mesocrystals showed an enhanced microbial colonization indicating improved biofilm formation. These findings highlight the potential of photocatalytic pretreatment in modifying surface properties to boost degradation in soil, thus offering a promising strategy for reducing microplastic accumulation.

RevDate: 2025-09-26
CmpDate: 2025-09-26

Cedeño-Pinargote AC, Jara-Medina NR, Pineda-Cabrera CC, et al (2025)

Impact of Biofilm Formation by Vaginal Candida albicans and Candida glabrata Isolates and Their Antifungal Resistance: A Comprehensive Study in Ecuadorian Women.

Journal of fungi (Basel, Switzerland), 11(9): pii:jof11090620.

Candida albicans and Candida glabrata are key fungal pathogens linked to candidiasis, with rising concerns due to antifungal resistance and biofilm abilities. However, data from Latin America remains limited. This study assessed biofilm formation and antifungal susceptibility of vaginal Candida isolates from Ecuadorian women. Biofilm formation at 24 and 48 h was evaluated using biomass and CFU assays and the biofilm formation index. Antifungal resistance in planktonic cells and patient microbiota profiles were also analyzed. Biofilm assessment showed 57.14% of isolates were high biofilm formers, 33.33% intermediate, 4.76% low, and 4.76% non-formers. Planktonic susceptibility testing included fluconazole, voriconazole, posaconazole, caspofungin, anidulafungin, micafungin, flucytosine, and amphotericin B. Micafungin showed the lowest MBEC90 value among tested antifungals, with an average MIC of 0.15 µg/mL, MBIC90 of 1.26 µg/mL, and MBEC90 of 1.86 µg/mL. Fluconazole followed with MIC, MBIC90, and MBEC90 values of 4.19, 63.33, and 66.59 µg/mL. Flucytosine had the highest values (MIC = 11.36 µg/mL; MBIC90 = 244.71 µg/mL; MBEC90 = 245.33 µg/mL). Both micafungin and flucytosine produced similar reductions in viable biofilm cells (1.44 log CFU), while fluconazole induced a slightly lower reduction of 1.39 log CFU. Findings suggest echinocandins may be effective against biofilm-forming Candida in this Ecuadorian population subset.

RevDate: 2025-09-26
CmpDate: 2025-09-26

Liu M, B Liao (2025)

Modelling of Diffusion and Reaction of Carbon Dioxide and Nutrients in Biofilm for Optimal Design and Operation of Emerging Membrane Carbonated Microalgal Biofilm Photobioreactors.

Membranes, 15(9): pii:membranes15090269.

The biological performance and carbon dioxide (CO2) flux of the novel and emerging concept of a membrane carbonated microalgal biofilm photobioreactor (MC-MBPBR) for wastewater treatment were investigated using mathematical modelling in conjunction with the finite-difference method. A set of differential equations was established to model the performance of an MC-MBPBR. The impacts of CO2 partial pressure, wastewater characteristics, and biofilm thickness on the concentration profiles and fluxes of CO2 and nutrients (N and P) to the biofilm of the MC-MBPBR were systematically studied. The modelling results showed profound impacts of these parameters on process efficiency (CO2 transfer and N and P removals) and the existence of an optimal biofilm thickness for maximum CO2, N, and P fluxes into the biofilm. Penetration of CO2 through the biofilm into the bulk water phase might occur under certain conditions. An increase in gaseous CO2 and increased influent N and P concentrations led to higher CO2, N, and P fluxes. The optimal biofilm thickness varied with the change in wastewater characteristics and gaseous CO2 concentration. The modelling results were in relatively good agreement with experimental results from the literature. The proposed mathematical models can be used as a powerful tool to optimize the design and operation of the novel MC-MBPBR for wastewater treatment and microalgae cultivation.

RevDate: 2025-09-26
CmpDate: 2025-09-26

de Andrade JG, Natali AFF, Loureiro C, et al (2025)

Synergistic Effect of Sodium Hypochlorite and Carbon Dioxide Against Enterococcus faecalis Biofilm.

Dentistry journal, 13(9): pii:dj13090417.

Objectives: This study aimed to evaluate whether the addition of pressurized carbon dioxide (PCD) influences the antimicrobial efficacy of 2.5% sodium hypochlorite (NaOCl) against Enterococcus faecalis biofilm in root canals and dentinal tubules. Methods: Forty extracted human mandibular premolars with single canals were contaminated with E. faecalis for 10 days and randomly assigned to four groups (n = 10): 2.5% NaOCl, 2.5% NaOCl + CO2, sterile saline, and sterile saline + CO2. The pH and temperature of the NaOCl solution were measured before and after CO2 incorporation. Microbial load was assessed by CFU counts before and after irrigation, and in dentin samples from the cervical, middle, and apical thirds. Oxidative stress was evaluated via lipid peroxidation (TBARS), protein carbonyl content, and total protein quantification. Biofilm metabolic activity was analyzed using the XTT reduction assay. Data were analyzed using one-way ANOVA on ranks and two-way repeated measures ANOVA (α = 0.05), a very large effect size (Cohen's d) ≈ 1.756 was assumed. Results: All irrigation protocols significantly reduced bacterial load (p < 0.05). Both NaOCl groups outperformed the saline controls (p = 0.009). The addition of CO2 to NaOCl slightly enhanced disinfection in the main canal but did not improve antimicrobial action in dentinal tubules. CO2 incorporation reduced the pH of NaOCl from ~13.4 to 7.4 and slightly increased the temperature, making the solution more chemically reactive. However, both oxidative stress markers and the XTT assay showed that the combination with CO2 impaired the antimicrobial effectiveness of NaOCl. Conclusions: Despite the improvement in bacterial reduction in the root canal lumen, the combination of PCD with NaOCl failed to enhance intratubular disinfection and reduced the oxidative damage and metabolic inactivation of the biofilm. CO2 pressurization appears to limit the antimicrobial action of NaOCl.

RevDate: 2025-09-26
CmpDate: 2025-09-26

Bao H, Yu F, Dai P, et al (2025)

Construction of an Electrochemical Impedance Spectroscopy Matching Method Based on Adaptive Multi-Error Driving and Application Testing for Biofilm Impedance Verification.

Biosensors, 15(9): pii:bios15090604.

Electrochemical impedance spectroscopy (EIS) is a technique used to analyze the kinetics and interfacial processes of electrochemical systems. The selection of an appropriate equivalent circuit model for EIS interpretation was traditionally reliant on expert experience, rendering the process subjective and prone to error. To address these limitations, an automated framework for both model selection and parameter estimation was proposed. The methodology was structured such that initial model screening was performed by a global heuristic search algorithm, adaptive optimization was guided by an integrated XGBoost-based error feedback mechanism, and precise parameter estimation was achieved using a Differential Evolution-Levenberg-Marquardt (DE-LM) algorithm. When evaluated on a purpose-built dataset comprising 4.8 × 10[5] spectra across diverse circuit and biofilm scenarios, a model classification accuracy of 96.32% was achieved, and a 72.3% reduction in parameter estimation error was recorded. The practical utility of the method was validated through the quantitative analysis of bovine serum albumin-Clenbuterol hydrochloride (BSA-CLB), wherein an accuracy of 95.2% was demonstrated and a strong linear correlation with target concentration (R[2] = 0.999) was found. Through this approach, the limitations of traditional black-box models were mitigated by resolving the physical meaning of parameters. Consequently, the automated and quantitative monitoring of processes such as biofilm formation was facilitated, enabling the efficient evaluation of antimicrobial drugs or anti-fouling coatings.

RevDate: 2025-09-26
CmpDate: 2025-09-26

Yöney B, Obořilová R, Lacina K, et al (2025)

Pathogen-on-a-Chip: Impedance-Based Detection of Biofilm Formation of Staphylococcus aureus and Staphylococcus epidermidis.

Biosensors, 15(9): pii:bios15090596.

Bacterial biofilms are complex microbial communities that contribute to the pathogenesis of chronic infections. Therefore, it is crucial to detect biofilm-associated infections in early stages as their delayed treatment becomes more complicated. Herein, we describe a label-free electrochemical impedance spectroscopy (EIS) method for detecting biofilm formation by Staphylococcus aureus and Staphylococcus epidermidis. Printed circuit board-based biamperometric gold electrodes were modified with poly-L-lysine to enhance bacterial attachment to the sensor surface. Formation and inhibition of biofilms were evaluated based on changes in charge transfer resistance (Rct). The control Rct value increased by ~90 kΩ for S. epidermidis biofilm and by ~60 kΩ for S. aureus biofilms. Antibiotic-treated samples exhibited similar values to those using the control. In addition, biofilm formation was evaluated through optical microscopy using safranin staining, and the micrographs suggest significant biomass on the electrodes, whereas the control appeared clear. Atomic force microscopy was used to visualize the biofilm on the electrode surface, obtain cross-sectional profiles, and evaluate its roughness. The roughness parameters indicate that S. aureus forms a rougher biofilm than S. epidermidis, while S. epidermidis forms a more compact biofilm. These findings suggest that the optimized EIS-based method effectively monitors changes related to biofilms and serves as a promising tool for evaluation of new anti-biofilm agents, such as antibiotics, phages or antibodies.

RevDate: 2025-09-26

Giovanni A, Shi YZ, Wang PC, et al (2025)

Comparative Evaluation of Oral Biofilm and Killed Cell Vaccines Against Streptococcus iniae in Four-Finger Threadfin Fish (Eleutheronema tetradactylum): Immune Response and Protection Efficacy.

Journal of fish diseases [Epub ahead of print].

Mariculture, a significant component of the maritime industry that focuses on marine food production, faces challenges in maintaining productivity during bacterial disease outbreaks, particularly in high-value aquaculture such as the four-finger threadfin fish in Taiwan. Streptococcosis, caused by Streptococcus iniae, is a major contributor to the mortality of the four-finger threadfin (Eleutheronema tetradactylum). Recurrent streptococcosis outbreaks have highlighted the pressing need for highly effective vaccination strategies. Given its safety, environmental friendliness, and protective effects, vaccination is widely acknowledged as an effective means of preventing aquatic diseases. An innovative approach involves using biofilm-forming S. iniae as vaccine candidates for aquaculture. This study presents an effective approach for developing a biofilm-based vaccine by cultivating S. iniae on chitosan particles, facilitating robust biofilm formation and enhancing immune responses in four-finger threadfin fish. For comparison, a formalin-killed cell (FKC) vaccine, prepared from whole-cell S. iniae, was evaluated. Immune responses were examined in the blood, mucus, and gut lavage from both the vaccinated and control groups. These responses include immune-related gene expression, antibody titers, and lysozyme activity. At 30 days post-vaccination, the biofilm vaccine group exhibited elevated antibody titers, with values of 0.23 ± 0.02 in serum, 0.09 ± 0.01 in mucus, and 0.16 ± 0.01 in gut lavage. Following vaccination, both the FKC and biofilm vaccines significantly upregulated the expression of key proinflammatory cytokines (tumour necrosis factor-α, interleukin [IL]-10, IL-12) in the spleen and kidney, indicating robust activation of the innate immune response. However, the biofilm vaccine induced markedly higher expression of these cytokines, highlighting its stronger stimulation of innate immune responses. These results suggest that the biofilm-based formulation stimulates early immune signalling pathways that are critical for protection against S. iniae infection. In the challenge experiments, the relative percent survival was of 22.85% for the biofilm and 42.8% for the FKC vaccine groups. This study demonstrates that while both FKC and biofilm vaccines activated innate and adaptive immunity, the FKC vaccine provided higher protection (RPS 42.8% vs. 22.85%), indicating that strong immunogenicity does not always translate into effective protection and that oral vaccine strategies require further refinement. Further optimisation of oral vaccine formulations is required to improve the protective efficacy of biofilm-based vaccines in aquaculture.

RevDate: 2025-09-26

Li L, Zhao Z, Gao Y, et al (2025)

Dynamic Metal-Phenolic Coordinated Hydrogel for Synergistic Photothermal/Chemodynamic Therapy against Biofilm-Infected Wounds and Real-Time Monitoring.

ACS applied materials & interfaces [Epub ahead of print].

The development of multifunctional hydrogel dressings integrating injectability, self-healing capability, tissue adhesion, multimodal antibacterial mechanisms, and real-time wound status monitoring remains a critical challenge for combating bacterial biofilms and accelerating wound healing. Herein, we present a dynamically cross-linked nanocomposite hydrogel (QCS-TA/LDH-panis) via Fe[3+]/Mn[2+]-mediated coordination between tannic acid (TA)-modified quaternized chitosan (QCS-TA) and polysulfonatoaniline-intercalated FeMn-layered double hydroxide (LDH-panis). The LDH-panis nanohybrids, synthesized through in situ polymerization of 3-sulfonatoaniline within FeMn-LDH interlayers, exhibit a near-infrared (NIR)-responsive photothermal effect (η = 64.3%) and pH/H2O2-activated peroxidase-like activity for biofilm-disrupting hydroxyl radical ([•]OH) generation. Concurrently, the QCS-TA matrix enables a "capture-and-kill" mechanism via electrostatic interactions (quaternary ammonium groups) and bacterial affinity adhesion (catechol/pyrogallol moieties). Under near-infrared (NIR) irradiation, synergistic mild photothermal/chemodynamic therapy (mPTT/CDT) combined with contact-killing achieved >95% eradication of Staphylococcus aureus and Escherichia coli biofilms. Notably, the hydrogel's conductivity enabled real-time monitoring of wound exudate and temperature fluctuation during the healing progression. In vivo evaluations confirmed accelerated infected wound regeneration (98.2% closure in 12 days) through biofilm elimination, inflammatory suppression, reepithelialization, and collagen deposition. This multifunctional hydrogel unifies dynamic adaptability, multimodal antibacterial therapy, and sensing intelligence, offering a promising strategy for the clinical management of biofilm-associated infection.

RevDate: 2025-09-26
CmpDate: 2025-09-26

Li J, Squyres GR, Duong K, et al (2025)

Extracellular matrix chemistry tunes bacterial biofilm metabolism and optimizes fitness.

bioRxiv : the preprint server for biology pii:2025.09.18.677115.

Chemically complex extracellular matrices define cellular microenvironments and shape cell behavior. We hypothesized a composition-properties-function relationship in these natural living materials, where interactions among matrix components govern material properties and cellular physiology. Using Pseudomonas aeruginosa biofilms as a model system, we show that electrostatic interactions between the cationic polysaccharide Pel and extracellular DNA (eDNA) regulate retention of pyocyanin (PYO), a redox-active metabolite that supports anaerobic metabolism via extracellular electron transfer (EET). Biofilm-mimetic hydrogels and natural biofilms revealed that altering Pel's charge via pH adjustment or chemical acetylation, or tuning the Pel:eDNA ratio, predictably modulates PYO retention and EET efficiency. Functionally, a lower Pel:eDNA ratio enhances metabolism under oxygen limitation, whereas a higher ratio promotes survival under antibiotic stress. These findings highlight how matrix chemistry encodes tunable material properties that confer biofilm fitness advantages and establish a materials-based framework for understanding extracellular matrices in multicellular communities.

RevDate: 2025-09-26
CmpDate: 2025-09-26

Gloag E, Marshall CW, Kubota N, et al (2025)

Pseudomonas aeruginosa biofilm-deficient mutants undergo parallel adaptation during chronic infection.

bioRxiv : the preprint server for biology pii:2025.09.20.677542.

Pseudomonas aeruginosa readily adapts to infection by acquiring stable and heritable mutations. Previously, we discovered that the first adaptations in a porcine wound model were rugose small-colony variants (RSCVs) caused by mutations in the wsp operon. These mutants overproduce Pel and Psl biofilm exopolysaccharides that improve defense against host responses. To identify other mechanisms of host adaptation that lead to hyperbiofilm phenotypes, we created a mutant with an activated wsp pathway but unable to produce these exopolysaccharides. Porcine wounds were infected with this mutant and biopsies were sampled at days 7, 14 and 35. Small colony variants were isolated from the wound, and whole genome sequencing revealed these variants had acquired mutations in genes in lipopolysaccharide and type IV pili biosynthesis, with wzy and pilU genes being most commonly targeted. pilU mutants were associated with a hyperbiofilm phenotype that outcompeted the parental strain, and wzy mutants were associated with a hyperbiofilm phenotype and increased tolerance to host antimicrobial products. We further identified that several variants had acquired large genome deletions that spanned up to 320 consecutive genes and other variants with high copy numbers of Pf6 filamentous phage. Together our results suggest that the hyperbiofilm phenotype is adaptive in chronic infections and that P. aeruginosa has redundant and diverse pathways to generate this phenotype.

RevDate: 2025-09-26

Piovesan LF, de Lima Fontes M, Gimenes MDS, et al (2025)

Orodispersible film based on hyaluronic acid and morin for dental biofilm control.

Biofouling [Epub ahead of print].

Orodispersible films (ODFs) are an innovative oral drug delivery method benefiting pediatric, geriatric, and non-compliant patients. They are portable, easy to swallow, and enhance bioavailability. Hyaluronic acid (HA) stands out among hydrophilic polymers for oral delivery of antimicrobial agents. This study evaluated the physicochemical properties, in vitro release profile, and antimicrobial/antibiofilm activity of HA-based ODFs combined with the flavonoid morin, known for its antimicrobial properties. Antimicrobial activity and microbial viability were assessed via biomass quantification. The films were thin (12-27 µm), flexible, homogeneous, and mechanically resistant. A burst release of morin was observed, reaching complete release at 210 min. Cytotoxicity analysis confirmed the non-toxic profile, showing cell viability. HA-morin films significantly reduced Streptococcus mutans biofilm mass, viability, and acidogenicity compared to the controls. Findings confirmed the non-toxic, and their significant antibiofilm activity against S. mutans. This innovative mucoadhesive system has potential for managing dental diseases and oral drug delivery.

RevDate: 2025-09-25
CmpDate: 2025-09-26

Khan MS, Jahan N, Khatoon R, et al (2025)

Risk factors and clinical outcomes of multidrug-resistant and biofilm-producing infections in diabetic foot ulcers: a two-year cohort study.

World journal of microbiology & biotechnology, 41(10):346.

This two-year prospective study analysed 124 diabetic foot ulcer (DFU) patients admitted to the Department of Surgery to identify clinical and microbiological predictors of multidrug-resistant (MDR) and biofilm-producing infections. The cohort was predominantly male (82.3%), with a mean age of 54.3 ± 11.6 years and a high prevalence of tobacco use (63%) and illiteracy (48.4%). Most patients (91.1%) exhibited poor glycaemic control (mean HbA1c 8.3 ± 1.3%), with neuropathy (79%) and retinopathy (72.6%) as the most common comorbidities. Ulcer severity ranged from Wagner grade 1 to 4, with 60.5% persisting for over one month. Microbiological analysis revealed 59.7% monomicrobial and 33.9% polymicrobial infections, with biofilm formation detected in 60.5% of isolates. Multivariable logistic regression showed significant associations between MDR isolates and tobacco use (OR: 4.06, P = 0.049), polymicrobial infections (OR: 20.75, P < 0.001), and biofilm formation (OR: 3.84, P = 0.033). Predictors of biofilm production included male sex (OR: 7.89, P = 0.023), neuropathy (OR: 4.44, P = 0.040), prolonged ulcer duration (OR: 0.09, P = 0.001), non-necrotic ulcers (OR: 0.16, P = 0.014), and MDR organisms (OR: 3.64, P = 0.034). Clinical outcomes included a 30.6% amputation rate (22.6% minor, 8.1% major) and an 8.9% mortality rate, with a mean hospital stay of 22.9 ± 9.2 days. These findings highlight the multifactorial nature of MDR development and biofilm-associated infections, emphasizing the critical roles of biofilm formation, polymicrobial infections, and tobacco use in DFU management. Early intervention and tailored therapies are essential to mitigate these risks and improve patient outcomes.

RevDate: 2025-09-25

Pourhajibagher M, Moghaddam EK, Moeininejad M, et al (2025)

Ex vivo assessment of blue laser-activated berberine-loaded nanoniosomes in enhancing photodynamic therapy against Streptococcus mutans biofilm on tooth enamel.

Photodiagnosis and photodynamic therapy pii:S1572-1000(25)00760-4 [Epub ahead of print].

BACKGROUND: Dental caries is a biofilm-mediated disease primarily caused by Streptococcus mutans, which produces extracellular polysaccharides via glucosyltransferases such as GtfB, promoting biofilm formation and cariogenicity. Photodynamic therapy (PDT) has gained attention as a promising alternative to conventional antimicrobials. This study investigates the efficacy of blue laser-activated berberine-loaded nanoniosomes (nNios@Ber) in enhancing PDT against S. mutans biofilms formed on tooth enamel.

MATERIALS AND METHODS: An ex vivo model using human tooth enamel slabs was employed to cultivate S. mutans biofilms. Berberine was encapsulated in nanoniosomes (nNios@Ber) to improve stability and delivery. Following determination of minimum inhibitory concentration (MIC) of nNios@Ber, biofilms were treated with various concentrations of nNios@Ber combined with blue laser irradiation (405 ± 10 nm nm) to activate PDT. Additionally, quantitative real-time PCR was used to quantify gtfB gene expression.

RESULTS: The MIC of nNios@Ber against S. mutans was found to be 15.6 μg/mL. All PDT-treated groups showed significant reductions in biofilm viability and a dose-dependent downregulation of gtfB expression. Specifically, gtfB expression decreased by 4.8-, 5.7-, and 7.4-fold in the 2 × MIC, 4 × MIC, and 8 × MIC nNios@Ber plus blue laser groups, respectively (P < 0.05). Neither nNios@Ber nor laser alone produced statistically significant effects (P > 0.05). These findings confirm that nNios@Ber's anti-biofilm efficacy is enhanced when photoactivated by blue laser.

CONCLUSION: Blue laser-activated nNios@Ber significantly inhibit S. mutans biofilm formation and virulence gene expression, offering an effective and targeted approach for caries management. This photoactivated nNios@Ber enhances the photodynamic activity, providing a promising adjunct or alternative to conventional antimicrobial agents such as CHX in oral healthcare.

RevDate: 2025-09-25

Lim TW, Lee J, Ab Ghani SM, et al (2025)

Ultrasonic Cleaning and its Effects on Denture Biofilm: A Systematic Review.

International dental journal, 75(6):103921 pii:S0020-6539(25)03205-8 [Epub ahead of print].

INTRODUCTION AND AIMS: Denture biofilm is associated with various oral and systemic diseases. Therefore, an effective denture-cleaning method should be adopted by denture wearers. This systematic review aimed to evaluate the efficacy of ultrasonic denture cleaning in reducing plaque quantity and microbial load and changing the microbial composition.

METHODS: Clinical studies published in English with no restriction on the year of publication that compared ultrasonic denture cleaning with other cleaning methods were included. Literature was searched across 5 electronic databases (PubMed, Embase, Web of Science, Scopus, and Cochrane Central Register for Controlled Trials). An additional search via other methods was performed until June 2025. The Revised Cochrane Handbook risk-of-bias tools (RoB 2) for individually randomised and parallel-group trials, cluster-randomised trials, and crossover trials were employed for the risk of bias assessments. A narrative synthesis of the included studies was generated.

RESULTS: A total of 2,811 articles were identified. Fifteen studies underwent full-text article screening, and an additional 4 articles were added through manual search. Ultimately, 10 randomised controlled clinical trials reporting the efficacy of ultrasonic denture cleaning contributed to this review. All included studies, assessed using the RoB 2, were considered to be of 'some concerns' to a 'high risk' of bias. The present review identified a diverse range of ultrasonic cleaning protocols. From the synthesis of the 10 included studies, positive outcomes were observed in reducing denture plaque quantity and microbial load, particularly when a chemical cleansing method was combined with ultrasonic cleaning.

CONCLUSION: There was consistent evidence from randomised clinical trials that supported ultrasonic cleaning reduced denture plaque quantity and modified microbial load, particularly when supplemented with an effervescent denture cleanser.

CLINICAL RELEVANCE: Ultrasonic cleaning combined with chemical cleansing should be adopted by older adults to reduce denture plaque coverage and microbial loads.

RevDate: 2025-09-25

Ivanov M, Đorđevski N, Dabić J, et al (2025)

Cutibacterium acnes growth and biofilm formation is inhibited by flavonoids.

Natural product research [Epub ahead of print].

Cutibacterium acnes is the cause of inflammatory acne and implanted devices associated infections. This study investigated flavonoids belonging to the 4 classes: flavanones (hesperidin, neohesperidin, naringenin, naringin, and eriodictyol), flavones (diosmetin, diosmin), isoflavone (genistein), and flavonols (kaempferol, galangin) as inhibitors of C. acnes growth in planktonic and biofilm form and assessed its potential to impact the integrity of cell membrane. Flavonoids could inhibit C. acnes growth, minimal inhibitory concentration (MIC) was in range 50-200 mg/L, with the lowest MIC (50 mg/L) for neohesperidin and eriodictyol. Minimal biofilm inhibitory concentrations were in range 25-200 mg/L, with the lowest values and highest antibiofilm potential recorded for eriodictyol, genistein, and kaempferol. Impact on cell membrane was significant in the presence of almost all examined flavonoids, as determined by crystal violet uptake assay. Flavonoids, especially eriodictyol, represent promising underexplored agents for combating infections and processes linked with the presence of C. acnes.

RevDate: 2025-09-25

Jenjitwanich A, Marx H, M Sauer (2025)

Metabolic Shifts Induced by pH Variation in Yarrowia lipolytica Biofilm.

FEMS microbiology letters pii:8263926 [Epub ahead of print].

The yeast Yarrowia lipolytica adapts its metabolite production based on cultivation conditions, with the pH value playing a critical role. At pH 3, most Y. lipolytica strains produce polyols, while at pH 5, they accumulate predominantly organic acids. Y. lipolytica has demonstrated the ability to transition from a planktonic, free-floating state to an immobilized state as a biofilm. This study aims to clarify the effects of pH level and carbon sources on the physiological state of Y. lipolytica when grown in a biofilm state. These pH variations were applied to the same biofilm culture to assess the capacity of given Y. lipolytica cells to undergo metabolic shifts and recovery under changing environmental conditions. Interestingly, a pH shift from 3 to 5 leads-as expected-to a metabolic shift from polyols to citric acid. However, the shift back to pH 3 does not revert back to polyols as major products. This study not only revealed an unexpected production pattern but also provided benefits for the industrial process in general. Understanding biofilm cultivation methods supports continuous bioprocesses using the immobilized nature of biofilm. pH-alternating experiments reveal how environmental condition fluctuations affect biofilm culture physiology.

RevDate: 2025-09-25
CmpDate: 2025-09-25

Martins SB, Teixeira SC, de Souza G, et al (2025)

In vitro assessment of Brazilian red propolis against mycobacteria: antibacterial potency, synergy, inhibition of biofilm formation, and intramacrophage effects.

Frontiers in pharmacology, 16:1630134.

BACKGROUND: Tuberculosis persists as a major global health threat and remains the leading cause of death from infectious disease. Efforts to control the disease are increasingly hampered by the emergence of drug-resistant Mycobacterium tuberculosis strains. At the same time, non-tuberculous mycobacteria are an expanding clinical concern, with few effective therapies available. Brazilian red propolis (BRP) has shown broad-spectrum antibacterial activity, yet its efficacy against mycobacteria is poorly characterized.

METHODS: This study evaluated the in vitro antimycobacterial potential of a crude hydroalcoholic extract of BRP (CHEBRP). Minimum inhibitory concentrations were determined against drug-susceptible and rifampicin-resistant M. tuberculosis strains (M. tuberculosis H37Rv-ATCC 27294, clinical isolate, and rifampicin-resistant clinical isolate; M. kansasii ATCC 12478 and clinical isolate; M. avium ATCC 25291 and clinical isolate). Fractional inhibitory concentration indices were calculated to assess interactions with isoniazid and rifampicin. Biofilm inhibition was measured, and cytotoxicity was assessed in RAW 264.7 macrophages. Intracellular activity was quantified using infected macrophage cultures.

RESULTS: CHEBRP exhibited potent activity against most M. tuberculosis strains tested, including rifampicin-resistant strains. Its combination with isoniazid or rifampicin yielded an indifferent interaction, supporting the feasibility of co-administration. CHEBRP significantly inhibited biofilm formation, showed minimal cytotoxicity toward macrophages, and achieved substantial clearance of intracellular bacilli.

CONCLUSION: These in vitro findings highlight CHEBRP as a promising candidate for adjunctive antimycobacterial therapy. Further studies should investigate its in vivo efficacy, pharmacokinetics, and activity against a broader range of mycobacterial species.

RevDate: 2025-09-25

Wang S, Cai L, Edwards AN, et al (2025)

Pseudomonas aeruginosa Adhesion and Biofilm Formation on Poly(l-lysine)-Tethered Hydrogels: Synergistic Effect of Substrate Stiffness and Positive Charge Density.

Langmuir : the ACS journal of surfaces and colloids [Epub ahead of print].

Infections associated with antibacterial-resistant Pseudomonas aeruginosa (P. aeruginosa) are the major cause of morbidity and mortality of patients, presenting one of the greatest therapeutic challenges for treatment of community-acquired and nosocomial infections. To develop antimicrobial hydrogel coatings to control the adhesion and subsequent biofilm formation of P. aeruginosa, we have used photo-cross-linked poly(ethylene glycol) diacrylate (PEGDA) hydrogels with varied cross-linking densities and covalently grafted poly(l-lysine) (PLL) at different weight compositions (ϕPLL). Both surface stiffness and positive charge density of the hydrogels were efficiently tuned over a broad range to investigate their effects on two main strains of P. aeruginosa, PA01 and PA14. We found that both number and viability of attached cells were positively correlated with the hydrogel stiffness, leading to thicker and larger coverage of cell colonies at 72 h postseeding on the stiffer substrates. The dependence of both PA01 and PA14 strains on ϕPLL, however, was nonmonotonic. Positive charges from dissociated amine groups in the grafted PLL chains significantly promoted initial adhesion and proliferation of both strains at low ϕPLL and developed into the thickest biofilms on the stiffest hydrogels grafted with ϕPLL of 1-2%. Nevertheless, on the softest hydrogels grafted with PLL at high ϕPLL of 7-10%, the bacteria no longer attached or survived. These results not only improved our fundamental understanding of bacteria-material interactions but also provided a series of PLL-grafted PEGDA hydrogels with controlled stiffness and positive charge density as ideal surface coating materials to prevent bacterial infections.

RevDate: 2025-09-24

Kobayashi F, Kawahara T, Narai-Kanayama A, et al (2025)

Nanobubble water for the effective removal of biofilm formed by Escherichia coli.

Journal of microbiological methods pii:S0167-7012(25)00192-7 [Epub ahead of print].

The removal of biofilm (BF) formed by Escherichia coli using nanobubble (NB) water prepared with different gases and two generation methods was investigated. The E. coli BF removal efficiencies of all NB water samples tested were significantly higher than those of the non-NB water. In particular, nitrogen (N2) NB water exerted the greatest effect on the removal of E. coli BF. The surface tension of N2NB water was the lowest, although that of airNB water was the highest. The dissolved oxygen (O2) concentration in the O2NB water was drastically increased, although that in the N2NB and carbon dioxide (CO2) NB water was decreased. The pH of CO2NB water was significantly decreased, although that of N2NB, airNB, and O2NB water was increased. The E coli BF removal efficiencies of N2NB water were not different in the NB generators between ejector and shearing types. However, the surface tension, pH, and size distribution varied among the NB generator types. Therefore, it was found that NB water removed E. coli BF, and that its efficiencies differed depending on the gas type.

RevDate: 2025-09-24
CmpDate: 2025-09-24

Hansen KH, Golcuk M, Byeon CH, et al (2025)

Structural basis of Pseudomonas biofilm-forming functional amyloid FapC formation.

Science advances, 11(39):eadx7829.

Biofilm-protected Pseudomonas aeruginosa causes chronic infections that are difficult to treat. FapC, the major biofilm-forming functional amyloid in Pseudomonas, is essential for biofilm integrity, yet its structural details remain unresolved. Using an integrative structural biology approach, we combine a solution nuclear magnetic resonance-based structural ensemble of unfolded monomeric FapC, a ~3.3-angstrom-resolution cryo-electron microscopy (cryo-EM) density map of FapC fibril, and all-atom molecular dynamics (MD) simulations to capture the transition from the unfolded to folded monomer to the fibrillar fold, providing a complete structural view of FapC biogenesis. Cryo-EM reveals a unique irregular triple-layer β solenoid cross-β fibril composed of a single protofilament. MD simulations initiated from monomeric and fibrillar FapC mapped structural transitions, offering mechanistic insights into amyloid assembly and disassembly. Understanding FapC reveals how Pseudomonas exploits functional amyloids for biofilm formation, and establishes a structural and mechanistic foundation for developing therapeutics targeting biofilm-related infection and antimicrobial resistance.

RevDate: 2025-09-24
CmpDate: 2025-09-24

Rasheed N, Ali X, -Ud-Din S, et al (2025)

The function of Anr in the differential effects of oxygen levels on biofilm development and nitrogenase performance in Pseudomonas stutzeri A1501.

PloS one, 20(9):e0333183 pii:PONE-D-25-31925.

Pseudomonas stutzeri A1501 exhibits a rare and notable trait: nitrogenase activity, which functions under microaerophilic conditions with limited oxygen availability. Optimal biofilm formation occurs in minimal media under nitrogen-depleted conditions. Anr is a transcription regulator with a widespread influence that accelerates the process of biofilm development. The lack of Anr adversely affects nitrogen fixation by regulating the activity of nifA, nifH, and ntrC. The anr insertion mutant significantly reduced the nitrogenase activity. Nitrogenase activity demonstrated considerable variation at different oxygen concentrations. The quantitative reverse transcription polymerase chain reaction (qRT-PCR) demonstrated a reduction in the expression of nif island genes during nitrogen fixation in the absence of anr gene. The discovery revealed that different oxygen levels in the environment significantly influence nitrogenase activity and biofilm formation. The qRT-PCR investigation demonstrated an upregulation of narL gene expression during biofilm formation, suggesting that reduced oxygen levels initiate a signaling cascade that activates the anr gene. This influences both the expression of RpoS (sigma factor) genes and the process of biofilm formation.

RevDate: 2025-09-24

Oster S, Bollinger E, Schreiner VC, et al (2025)

Functional stability despite structural changes in freshwater biofilm communities exposed to an antibiotic and an herbicide - the role of nutrient conditions.

FEMS microbiology ecology pii:8262894 [Epub ahead of print].

Freshwater autotrophic biofilms play a vital role in primary production and nutrient cycling in freshwater ecosystems but are increasingly exposed to chemical stressors such as antibiotics or herbicides. Although nutrient availability may modulate biofilm sensitivity, its impact on biofilm responses to these stressors remains poorly understood. In four independent experiments, we investigated the functional (ash-free dry weight and chlorophyll a, b and c) and structural (16S/18S rRNA metabarcoding) responses of stream-derived biofilms under low- and high-nutrient levels to chronic exposure (14 days) to the antibiotic ciprofloxacin and the herbicide propyzamide in laboratory stream microcosms. High-nutrient levels strongly increased biofilms functional responses and altered the community composition. Chemical exposure led to pronounced shifts in prokaryotic (ciprofloxacin) and eukaryotic (propyzamide) communities, but without significant effects on functional responses, suggesting functional redundancy and ecological buffering capacity of freshwater biofilms. These results highlight the critical role of nutrient supply in biofilm responses and the need for caution when extrapolating laboratory results to field conditions.

RevDate: 2025-09-24
CmpDate: 2025-09-24

Favaro JC, Geha O, Canavarros TN, et al (2025)

Addition of silver nanoparticles to universal adhesive: In vitro effect on biofilm and shear bond strength.

Brazilian dental journal, 36:e236255 pii:S0103-64402025000100226.

Silver nanoparticles (AgNPs) have been incorporated into dental materials at low concentrations to provide antibacterial action without compromising mechanical properties. This in vitro study evaluated the antibiofilm effect and bond strength of an experimental universal adhesive with AgNPs (EAg). Streptococcus mutans biofilm was induced by incubating samples with 0.01% and 0.02% AgNPs, based on a pilot study, compared to a control (experimental without AgNPs, ES) in a 20% sucrose medium. This was followed by sonication and counting of viable cells after 1 and 7 days (n = 9). Enamel and dentine bovine micro shear bond strength test (μ-SBS) was performed (n=10) with EAg0.01% and controls (ES and the commercial OPT (Optbond Universal; Kerr). μ-SBS data of enamel and dentin were evaluated for normality and homogeneity by Shapiro-Wilk and Levene, respectively, resulting in normality. Therefore, they were subjected to ANOVA. The failure type was evaluated using a stereoscopic magnifying glass at '40 and categorized as adhesive, cohesive, and mixed failure. The 0.01% concentration demonstrated the antibiofilm effect at the lowest AgNP concentration and was selected for the μ-SBS test. For μ-SBS ANOVA, there were no statistically significant differences between experimental and commercial adhesives (p<0.05). Evaluation of failure mode showed a predominance of adhesive failure on both substrates for all adhesives. The EAg exhibited antibiofilm activity with adhesive performance statistically similar to that of the commercial adhesive. Experimental universal adhesive containing silver nanoparticles showed antibacterial activity without compromising μ-SBS to enamel and dentin.

RevDate: 2025-09-24

Wang H, Li Y, Chen H, et al (2025)

Perfluorooctanoic Acid Can Increase Biofilm Resilience and Virulence in Drinking Water Distribution Systems.

Environmental science & technology [Epub ahead of print].

Despite the prevalence of perfluorooctanoic acid (PFOA) in drinking water distribution systems (DWDSs), its effects on biofilm formation and tolerance to residual disinfectants remain largely unknown. Here, we report that DWDS-relevant levels of PFOA (1-80 ng/L) promoted Pseudomonas aeruginosa biofilm formation (by 1.8- to 4.5-fold) and chlorine tolerance (by 7-22%). PFOA also enhanced biofilm tolerance to common antibiotics, increasing their minimum inhibitory concentrations by 25-67%. In a flow-through system, biofilm evolution toward higher resilience was attributed to PFOA-exerted oxidative stress, which fortuitously upregulated quorum sensing and stimulated extracellular polymeric substances production. PFOA exposure also increased bacterial chemotaxis and activated cyaA and cyaB genes, which enhanced the cAMP/Vfr signaling pathway, contributing to the upregulation of virulence factor genes. PFOA-induced chlorine and antibiotic resistance and increased virulence were also verified with a mesocosm system and a real DWDS pipeline biofilm. Overall, these results underscore the need for proactive microbial risk assessment associated with such indirect effects of emerging pollutants in DWDSs.

RevDate: 2025-09-24

Fortes CV, Ribeiro AB, Wever B, et al (2025)

Evaluation of biofilm formation, adhesive strength and effectiveness of cleaning protocols on adhesive-containing acrylic resin specimens: An in vitro study.

Dental and medical problems [Epub ahead of print].

BACKGROUND: Denture adhesives promote greater stability and retention of dentures. However, they can also facilitate biofilm formation related to oral diseases.

OBJECTIVES: The study aimed to evaluate the influence of 2 adhesives on the microbial load of mixed biofilm and adhesive strength. Additionally, the objective was to assess the effect of 3 hygiene protocols on the microbial load and cell metabolism of this biofilm.

MATERIAL AND METHODS: The study compared Corega Ultra Cream (CCA) and OlivaFix® Gold (OFA) adhesives by evaluating the biofilm formation of Candida albicans, Candida glabrata, Staphylococcus aureus, and Streptococcus mutans by colony-forming unit (CFU), as well as adhesive strength. The implemented hygiene protocols included brushing and immersion in water (BW), 0.15% triclosan (BT0.15%), or 0.25% sodium hypochlorite (BSH0.25%). The control groups were either without adhesive (CG) or without any hygiene protocols (CGwH). The one-way and two-way analyses of variance (ANOVAs) with Tukey's post hoc test and a generalized linear model with Bonferroni adjustment were used for statistical analysis (α = 0.05).

RESULTS: The microbial load of C. albicans was higher when OFA was used (p < 0.001). The microbial loads of C. glabrata and S. mutans were similar between adhesives and higher in the CG (p < 0.001). The influence of the adhesives on the microbial load of S. aureus was not statistically significant (p = 0.287). The adhesive strength promoted by OFA was greater and more stable than when CCA was used (p = 0.007). The immersion in sodium hypochlorite led to a reduction in the microbial load of C. albicans (p < 0.001), C. glabrata (p = 0.002) and S. mutans (p = 0.012), independent of the adhesive. For S. aureus, the microbial load was lower with OFA/BSH0.25% (p = 0.022). All hygiene protocols resulted in a decreased cell metabolism when compared to the CGwH (p < 0.001).

CONCLUSIONS: Brushing with BSH0.25% solution was the most effective hygiene protocol, resulting in a reduction in the microbial load and metabolism. This protocol may be recommended as a first-line option for the disinfection of dentures.

RevDate: 2025-09-24
CmpDate: 2025-09-24

Salman SAK, BMM Al Muhana (2025)

Detection of biofilm genes in MDR Staphylococcus aureus isolated from human and cattle urinary tract infections in Babylon Governorate, Iraq.

Open veterinary journal, 15(6):2551-2561.

BACKGROUND: Staphylococcus aureus (S. aureus) is a major pathogenic bacterium in veterinary medicine and human health. It is one of the most important bacterial agents causing urinary tract infection (UTI). The increasing incidence of multidrug-resistant and biofilm-forming S. aureus is a great problem today. The aim of the study was to investigate the phenotypic and genotypic aspects of biofilm formation in multiple drug-resistant (MDR) S. aureus isolated from UTI infection in human and cattle in Babylon, Iraq.

METHODOLOGY: A total of 168 and 172 urine samples were collected from UTI infection in humans and cattle, respectively, during the period from November 2023 to February 2024. Morphological and biochemical identification was used to diagnose S. aureus. Additional confirmation was performed by the automated Vitek 2 compact system.

RESULTS: Among the 168 human isolates, 24 (14.2%) and 172 cattle isolates, 16 (9.3%) isolates were diagnosed as S. aureus. Genotypically identification of the isolates was performed using the 16s RNA gene. Twenty-two (91.6%) from 24 human source S. aureus isolates and 8 (50%) from 16 animal source S. aureus isolates were found to be MDR according to the Vitek 2 compact system. Results revealed that 19 (86.3%) and 7(87.5%) MDR isolates were phenotypically positive for biofilm production in concern to human and animal source isolates, respectively. Genotypically, three polysaccharide intracellular adhesion genes and one MSCRAMMs (fib) were screened in MDR bacteria using specific primers. The prevalence rate of genes was icaA (100%), icaB (100%), and icaC (100%) in all 30 MDR isolates. fib gene were present in 63.6% of human isolates and 75% of cattle source isolates.

CONCLUSION: The study has shown that the biofilm-forming S. aureus that causes UTI were resistant to multiple antibiotic agents. These findings underscore the necessity of development effective treatment approaches to control UTI infections in humans and animals.

RevDate: 2025-09-24
CmpDate: 2025-09-24

Strzelecki P, Ferté T, Klimczuk T, et al (2025)

Trans-Cinnamaldehyde-Driven Silver Nanoparticles: Dual Role in Targeting Biofilm Disruption and Control of Biofilm‑Forming Pathogens via Impairing Ferrous Ion Uptake.

Nanotechnology, science and applications, 18:387-403.

PURPOSE: Biofilm-related infections, especially those associated with medical devices like catheters, pose significant clinical challenges due to their resistance to conventional treatments. This study investigates a green chemistry-based approach to synthesize silver nanoparticles (AgNPs) stabilized with trans-cinnamaldehyde (t-CA) and evaluates their potential for combating microbial biofilms and based on novel mechanism of action.

METHODS: Silver nanoparticles (t-CA-AgNPs) were synthesized using t-CA as both a reducing and stabilizing agent. The NPs were then thoroughly characterized using UV-Vis spectroscopy, X-ray diffraction (XRD), electron microscopy (TEM, SEM, STEM), and dynamic light scattering (DLS). We evaluated its antimicrobial potential against the most prevalence biofilm-forming pathogens including Pseudomonas aeruginosa, Escherichia coli and Candida albicans using minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) assays. Moreover, we investigated the mechanism of action of t-CA-AgNPs underlying biofilm inhibition. Biofilm formation and structure were verified by SEM imagining.

RESULTS: DLS analysis confirmed that t-CA-AgNPs had an average particle diameter of 2.5 nm, coupled with a notably negative zeta potential (-45 mV), indicative of good colloidal stability. t-CA-AgNPs displayed potent antimicrobial properties, with MIC values ranging from 26 to 412 µg/mL and MBC values from 103 to 825 µg/mL. Biofilm formation inhibitory properties reached 88.74% of inhibition for P. aeruginosa and 70.60% for E. coli. Moreover, we found potent metal ion-chelating capabilities, importantly, in binding and reducing ferrous ions, the crucial factor of biofilm formation. Furthermore, t-CA-AgNPs substantially impaired biofilm development on catheter surfaces, underscoring their robust antibiofilm potential.

CONCLUSION: Presented here t-CA-AgNPs exhibit significant antimicrobial and antibiofilm activity. By effectively targeting critical elements in biofilm formation, such as ferrous ions, coupled with antimicrobial potential of both active compounds, these green-synthesized NPs have potential applications in significantly improving the safety and effectiveness of medical devices. However, further studies are needed to ensure their efficacy in clinical use.

RevDate: 2025-09-23

Rajalakshmi E, J L ES, Balakrishnan A, et al (2025)

Exploring the impact of quercetin on the growth and biofilm formation of Leptospira interrogans.

Folia microbiologica [Epub ahead of print].

Leptospira interrogans, the causative agent of leptospirosis, presents major challenges due to its ability to form environmental biofilms, persistent virulence, and emerging antimicrobial resistance. Plant-derived bioactive compounds offer promising alternatives to conventional antibiotics in targeting bacterial biofilms. This study investigates the antibiofilm and antimicrobial potential of quercetin, a plant-derived polyphenol, against L. interrogans. Quercetin significantly inhibited biofilm formation (91%), induced 44% biofilm dispersion at 500 µg/mL, and reduced viable cell counts by 92% at 1000 µg/mL compared to the untreated control. These effects were further validated using fluorescence-activated cell sorting (FACS), which demonstrated reduction in the live cells in the presence of quercetin. The expression levels of key genes associated with virulence and biofilm regulation were assessed using quantitative RT-PCR, revealing downregulation of csrA and upregulation of lipL32 in quercetin-treated cells. Potential molecular interactions between several leptospiral proteins and quercetin were proven through AutoDock Vina and PyMOL. These findings highlight quercetin's potential as an anti-leptospiral agent for managing leptospiral biofilm formation and dispersions.

RevDate: 2025-09-23

Zhao H, Dufour D, Ghobaei N, et al (2025)

DNA adenine methylation influences gene expression and biofilm formation in Streptococcus mutans.

Applied and environmental microbiology [Epub ahead of print].

UNLABELLED: Streptococcus mutans, a key oral pathogen, utilizes quorum sensing to regulate biofilm formation-a major virulence factor in the development of dental caries (tooth decay). Our recent research uncovered a complex interplay between the CSP-ComDE quorum sensing pathway and the Type II DpnII restriction-modification (R-M) system in S. mutans. The DpnII R-M system methylates adenine at 5'-GATC-3' sites and cleaves unmethylated DNA, significantly influencing foreign DNA acquisition and gene expression. In this study, we investigated the impact of a ΔRM mutant, which lacks adenine methylation, on biofilm formation. The ΔRM mutant formed fragile biofilms that easily detach from surfaces, with significantly reduced exopolysaccharide content and increased extracellular DNA, which appears to be associated with membrane vesicle production rather than cell lysis. RNA-seq analysis revealed only few differentially expressed genes directly involved in biofilm formation, such as gtfC, suggesting that the biofilm defect may result from indirect effects or alternative regulatory mechanisms. Notably, the downregulation of mutanobactin-related genes and upregulation of genes involved in de novo purine nucleotide biosynthesis point to novel pathways influenced by DNA methylation. These findings contribute to a deeper understanding of the multifactorial nature of biofilm formation and the role of epigenetic modifications in microbial behavior.

IMPORTANCE: This study highlights the critical role of DNA methylation in regulating biofilm formation and virulence in Streptococcus mutans. By examining the interplay between adenine methylation, extracellular DNA (eDNA), membrane vesicles (MVs), and glucan production, we provide new insights into the complex biology of biofilm development. Our findings challenge traditional views by emphasizing the importance of MVs and eDNA in maintaining biofilm integrity. Understanding these epigenetics modifications not only advances our knowledge of microbial regulation but also identifies novel targets for antimicrobial therapy. Since adenine methylation is rare or absent in mammalian cells, targeting this modification presents a promising strategy to disrupt biofilm formation and combat bacterial infections. The insights gained from this study may inform the development of innovative approaches to manage biofilm-associated infections and improve oral health outcomes.

RevDate: 2025-09-23

Arbulu S, Oftedal TF, M Kjos (2025)

Transcriptomic response in planktonic and biofilm-associated cells of S. mutans treated with sublethal concentrations of chlorhexidine.

FEMS microbiology letters pii:8262271 [Epub ahead of print].

Chlorhexidine, an antimicrobial with a broad inhibitory spectrum, is commonly used to treat oral infections as an active ingredient in mouthwash. While typically used at high concentrations (1-2 mg/ml), oral bacteria can be exposed to sublethal concentrations due to the bioavailability and protective barrier of biofilms (dental plaques). Sublethal concentrations can cause transcriptional remodelling of bacteria such as Streptococcus mutans, a key player in dental caries. Using an RNA-seq approach, this report provides a compendium on the effect of sublethal concentrations of chlorhexidine on the transcriptome of S. mutans as planktonic cells and in biofilm states. S. mutans showed major transcriptional remodelling between planktonic and biofilm states. The transcriptional response towards chlorhexidine was more pronounced in planktonic cells compared to sessile cells. However, the response observed for biofilm-associated cells was not specific to chlorhexidine, as the transcriptional response in biofilms exposed to the β-lactam amoxicillin was similar to those observed for chlorhexidine. Furthermore, we found that S. mutans modulates transcription of a multitude of ABC transporters both in planktonic and biofilm-associated cells upon exposure to these antimicrobials.

RevDate: 2025-09-23

Yang T, Han Y, Zhang M, et al (2025)

Quorum sensing enhances extracellular electron uptake of electrotrophic biofilm via metabolic cascade for aerobic biochemical oxygen demand sensing.

Bioresource technology, 439:133363 pii:S0960-8524(25)01330-6 [Epub ahead of print].

Electrotrophic biocathodes enable rapid biochemical oxygen demand (BOD) sensing but face challenges like slow colonization, low current, and poorly understood microbial interactions. This study employed exogenous quorum sensing signals (C6-HSL and 3O-C12-HSL) to enhance biofilm development on oxygen-reducing biocathodes. These two N-acyl-homoserine lactones (AHLs) accelerated formation and boosted current density 5-6 times. Candidatus Tenderia served as key electrotrophs, while non-electroactive Moheibacter promoted early adhesion and extracellular polymeric substance (EPS) production. Metagenomics showed upregulation of genes related to iron metabolism, adhesion, and electron transfer, alongside increased fulvic-like shuttle secretion. A cascade model was proposed: AHLs initiate non-electrotrophic EPS production, facilitating electrotrophs colonization and electron transfer. AHL-enhanced biofilm showed improved BOD sensing sensitivity and linearity, providing a new strategy and mechanistic basis for developing efficient biocathode biosensors.

RevDate: 2025-09-22

Chalana A, Thakur V, Gupta V, et al (2025)

Synergistic Combination of Imipenem and 7-Fluoroindole Inhibits β-lactamases and Biofilm in Carbapenem-resistant Acinetobacter baumannii.

Journal of applied microbiology pii:8261528 [Epub ahead of print].

BACKGROUND: Acinetobacter baumannii is a nosocomial opportunistic pathogen responsible for hospital and community-acquired infections. It has been categorised as a high-priority ESKAPE pathogen due to escalating resistance, underscoring the urgent need for effective treatment options. This study explores the use of 7-Fluoroindole (7-FI) as an adjuvant to imipenem for combating Carbapenem-Resistant Acinetobacter baumannii (CRAB).

METHODS: Clinical strains of A. baumannii were subjected to disc diffusion assay for antibiotic resistance profile, and Fractional Inhibitory Concentration (FIC) of 7-FI was determined with imipenem by checkerboard assay. Expression of β-lactamases, efflux pumps, and outer membrane proteins was determined by qRT-PCR. Biofilm inhibition by 7-FI in combination with imipenem was evaluated by Confocal Laser Scanning Microscopy.

RESULTS: 7-FI reduced the MIC of imipenem by 2 to 8-fold in CRAB strains, and also enhanced susceptibility to meropenem. Mechanistically, 7-FI inhibited the β-lactamase activity by 2.3 to 3.8-fold and downregulated the expression of Class B (blaNDM-1) and D (blaOXA-23 and blaOXA-51) β-lactamases. The efflux pump activity was reduced by 2 to 8.6-fold, and expression of efflux pump genes adeB, adeJ, abeM and emrA was also significantly (p < 0.001) downregulated. 7-FI in combination with imipenem inhibited biofilm formation by 80% even at 1 × FIC (1/4 MIC of imipenem and 1/3 MIC of 7-FI).

CONCLUSION: The combination of 7-FI and imipenem synergistically mitigated carbapenem resistance in A. baumannii by inhibiting the activity of β-lactamases, downregulating the expression of β-lactamases and efflux pumps. The study shows 7-FI as a useful adjuvant to imipenem against CRAB strains.

RevDate: 2025-09-22
CmpDate: 2025-09-22

Sakyi Opoku NYP, Mishra A, Fletcher H, et al (2025)

Enhancing Antimicrobial Susceptibility Testing for Acinetobacter baumannii Using Physiologically Relevant Culture Media and Biofilm Formation Assays.

Current protocols, 5(9):e70207.

Acinetobacter baumannii is a high-risk pathogen associated with increased patient morbidity and mortality. Host-pathogen interactions amplify its virulence, in part by promoting biofilm formation-a crucial factor in antimicrobial resistance and persistence. Given the bacterium's strong propensity for acquiring resistance, antimicrobial susceptibility testing (AST) is essential for guiding effective therapeutic interventions. However, discrepancies have been observed between in vitro AST results and therapeutic outcomes, with some antimicrobials being deemed to show in vivo efficacy despite appearing ineffective in vitro. This discordance may stem from traditional AST protocols, which rely on bacteriological media such as Mueller Hinton broth (MHB) optimized for bacterial growth but not for mimicking the host environment. Moreover, conventional AST does not account for virulence traits such as biofilm formation, which further contribute to treatment failure. Incorporating physiologically relevant culture media, such as Roswell Park Memorial Institute (RPMI) 1640 medium, alongside assessment of biofilm formation may improve the predictive value of AST. This work outlines two complementary protocols for improving AST interpretation in A. baumannii infections. Basic Protocol 1 compares minimum inhibitory concentration (MIC) values generated using MHB and RPMI. Basic Protocol 2 evaluates biofilm formation in MHB, tryptic soy broth (TSB; control), and RPMI, with and without antimicrobial exposure. Together, these approaches aim to inform alternative AST strategies that better reflect in vivo conditions and optimize therapeutic decision-making. © 2025 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Comparing A. baumannii minimum inhibitory concentration (MIC) results in bacteriological (MHB) versus physiological (RPMI) media Basic Protocol 2: Comparing A. baumannii isolate(s) biofilm formation following assays completed in bacteriological culture media (MHB and control TSB) and physiological medium (RPMI).

RevDate: 2025-09-22

Maree M, Ushijima Y, Krama A, et al (2025)

Mixed-biofilm natural transformation assay reveals the presence of staphylococci in human environments that can transfer SCCmec to Staphylococcus aureus.

mSphere [Epub ahead of print].

Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen that causes healthcare-, community-, and livestock-associated infections. The methicillin resistance gene mecA is embedded in the mobile genetic element termed Staphylococcal Cassette Chromosome (SCCmec). SCCmec is shared among staphylococci inhabiting human and animal hosts, which are recognized epidemiologically as the genetic reservoir of SCCmec. However, the ability of diverse methicillin-resistant staphylococci (MRS) to serve as SCCmec donors for S. aureus has not been tested experimentally. Here, we investigated the ability of 157 MRS isolates from pets, meat, livestock, and humans to transfer SCCmec to methicillin-sensitive S. aureus strains using a recently developed natural transformation protocol in mixed biofilms. We found that 25 out of 157 isolates were able to transfer SCCmec to S. aureus. The most effective donor species were S. epidermidis (~33% of the tested isolates), S. felis (40%), and S. capitis (30%). Isolates from meat and livestock (collected in Vietnam and Thailand) had lower transfer rates of SCCmec (5% and 3%, respectively), compared to human and pet isolates from Japan (35% and 25%, respectively). The SCCmec transfer depended on site-specific integration/excision mediated by an intact attB site, which is recognized by the SCC recombinase Ccr. Our study experimentally demonstrates the presence of SCCmec donors in our living environments, highlighting the importance of specific staphylococcal species.IMPORTANCEHow MRSA emerges has long been the pivotal question regarding the ever-increasing burden of antimicrobial resistance (AMR) issues for over half a century. Extensive research efforts in bacteriology, epidemiology, genome biology, and healthcare fields have led to the common understanding that SCCmec is transmitted among distinct staphylococcal species. However, global efforts to provide empirical evidence for intercellular SCCmec transmission have yielded limited results. We recently established the mixed-biofilm transformation assay to evaluate intercellular and interspecies SCCmec transmission. This novel assay system allows us to gain insight into the question "How MRSA emerges," and here, we provide the first experimental results about the potential donor species and habitats. This is the first report to show the ability of staphylococci from distinct sources to transfer SCC to S. aureus. Moreover, the new finding of S. felis as an effective donor that is not commensal to humans reinforces the importance of the One Health concept.

RevDate: 2025-09-22
CmpDate: 2025-09-22

García MT, Morán MC, Pons R, et al (2025)

Arginine-Derived Cationic Surfactants Containing Phenylalanine and Tryptophan: Evaluation of Antifungal Activity, Biofilm Eradication, Cytotoxicity, and Ecotoxicity.

Journal of xenobiotics, 15(5): pii:jox15050140.

Due to the growing emergence of bacterial and fungal resistance, there is an urgent need for novel antimicrobial compounds. Cationic surfactants are effective antimicrobial agents; however, traditional quaternary ammonium compounds (QACs) are increasingly scrutinized due to their cytotoxicity, poor biodegradability, and harmful effects on aquatic ecosystems. While the antimicrobial efficacy of many new biocides, including QACs, has been extensively studied, comprehensive experimental strategies that simultaneously assess antimicrobial activity, mammalian cell toxicity, and ecotoxicity remain limited. Recent studies have reported that amino-acid-based surfactants containing arginine-phenylalanine and arginine-tryptophan exhibit excellent antibacterial activity and are biodegradable. This work extends their biological characterization to evaluate their potential applications. Specifically, we examined how variations in the head group architecture and hydrophobic moiety influence antifungal and antibiofilm activity. We also assessed how these structural parameters impact cytotoxicity and ecotoxicity. These compounds demonstrated strong activity against a wide range of Candida strains. Their hydrophobic character primarily influenced both antifungal efficacy and cytotoxicity. Importantly, these surfactants exhibited potent antimicrobial and antibiofilm effects at non-cytotoxic concentrations. Notably, their aquatic toxicity was significantly lower than that of conventional QACs.

RevDate: 2025-09-22
CmpDate: 2025-09-22

Heine N, Bittroff K, Szafrański SP, et al (2025)

Influence of species composition and cultivation condition on peri-implant biofilm dysbiosis in vitro.

Frontiers in oral health, 6:1649419.

INTRODUCTION: Changes in bacterial species composition within oral biofilms, known as biofilm dysbiosis, are associated with the development of severe oral diseases. To better understand this process and help establish early detection systems, models are needed which replicate oral biofilm dysbiosis in vitro - ideally by also mimicking natural salivary flow conditions.

METHODS: For this purpose, the present study cultivated two different combinations of oral commensal and pathogenic strains - Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar/parvula, Fusobacterium nucleatum and Porphyromonas gingivalis - comparatively within an established flow chamber model on the implant material titanium, and statically in 6-well plates for 21 days. Biofilm morphology, species distribution, and bacterial metabolism were analyzed by fluorescence microscopy, molecular biological methods, and metabolic interaction prediction.

RESULTS: Biofilm growth and composition were strongly influenced by bacterial species selection, and to a more minor extent, by cultivation conditions. Within the model containing V. dispar and a laboratory P. gingivalis strain, a diversification of commensal species was observed over time along with a significantly reduced pH-value. In contrast, the model containing V. parvula and the clinical isolate P. gingivalis W83, a dysbiotic shift with increased pathogen levels, pH-value, and virulence factors was achieved.

CONCLUSION: Within the present study, different in vitro oral multispecies biofilm models were successfully developed. Depending on bacterial species selection, these models were able to depict the infection-associated dysbiotic shift in species composition under flow conditions solely by intrinsic interactions and without the use of external stimuli.

RevDate: 2025-09-22

Kivimaki SE, Dempsey S, Camper C, et al (2025)

Type IV Pili-Associated Secretion of a Biofilm Matrix Protein From Clostridium perfringens That Forms Intermolecular Isopeptide Bonds.

Molecular microbiology [Epub ahead of print].

Clostridium perfringens is a gram-positive, anaerobic, spore-forming bacterial pathogen of humans and animals. C. perfringens also produces type IV pili (T4P) and has two complete sets of T4P-associated genes, one of which has been shown to produce surface pili needed for cell adherence. One hypothesis about the second set of T4P genes is that they comprise a type II secretion system (TTSS) like those found in gram-negative bacteria, but for gram-positive bacteria, the TTSS would aid transit across the thick peptidoglycan (PG) layer. The secretome of mutants lacking type IV pilins was examined, and a single protein, BsaC (CPE0517), was identified as being dependent on pilin PilA3 for secretion. The bsaC gene is in an operon with genes encoding a SipW signal peptidase and two putative biofilm matrix proteins, BsaA and BsaB, both of which have remote homology to Bacillus subtilis biofilm protein TasA. Since BsaA forms long oligomers that are secreted, we analyzed BsaA monomer interactions with de novo modeling. These models projected that the monomers formed isopeptide bonds as part of a donor strand exchange process. Mutations in residues predicted to form the isopeptide bonds led to the loss of oligomerization, supporting an exchange and lock mechanism, and isopeptide bonds were detected by mass spectrometry methods. Phylogenetic analysis showed the BsaA family of proteins is widespread among bacteria and archaea, but only a subset is predicted to form isopeptide bonds.

RevDate: 2025-09-21

Eladl A, Abbas HA, Elbaramawi SS, et al (2025)

The anti-inflammatory drugs diclofenac and ketorolac inhibit urease activity and biofilm formation by uropathogenic Proteus mirabilis.

Folia microbiologica [Epub ahead of print].

Proteus mirabilis is a major bacterium responsible for catheter-associated urinary tract infections (CAUTIs). Urease enzyme has a great role in the pathogenesis of Proteus mirabilis. Using urease, Proteus mirabilis can decompose urea to produce ammonia that increases urine pH and enhances crystal precipitation and crystalline biofilm formation. This leads to catheter blockage and pyelonephritis, respectively. Urease inhibitors are of great value in controlling this problem. Diclofenac sodium and ketorolac tromethamine, with their metal chelating activities, can inactivate urease by chelation of nickel ion in the active site of urease. This study investigated the ability of diclofenac sodium and ketorolac tromethamine to inhibit urease activity in Proteus mirabilis and crystalline biofilm formation. Diclofenac sodium and ketorolac tromethamine showed comparable activities against urease in cell lysates and whole cultures, with subsequent inhibition of pH increase and crystal formation in artificial urine. Diclofenac sodium showed higher biofilm inhibition and downregulation of urease genes ureR and ureC in RT-qPCR. The docking study showed the ability of both drugs to bind to urease enzyme and to chelate nickel ions in the active site of urease, suggesting that nickel chelation is the mode of inhibition of urease enzyme. In conclusion, diclofenac sodium and ketorolac tromethamine are two urease inhibitors that may be useful in treating Proteus mirabilis CAUTI.

RevDate: 2025-09-21

Eltawab R, Li K, Abdelfattah A, et al (2025)

Harnessing methane for improved nitrogen removal in membrane aerated biofilm reactors: towards sustainable wastewater practices.

Bioresource technology pii:S0960-8524(25)01329-X [Epub ahead of print].

This review examines the role of methane as an electron donor in Membrane Aerated Biofilm Reactor (MABR) systems, which conventionally use gas-permeable membranes to deliver oxygen directly to stratified biofilms for wastewater treatment. The integration of methane provides a sustainable carbon source for denitrification while also mitigating methane emissions. Methanotrophic denitrification enables methanotrophs to couple methane oxidation with nitrate or nitrite reduction, linking nitrogen removal with greenhouse gas mitigation. This dual function improves treatment efficiency, reduces energy use and operational costs, and addresses drawbacks of conventional MABRs, such as limited denitrification in low-carbon wastewater, by supplying a cost-effective carbon source. Methane-based MABRs, however, introduce challenges including methane-oxygen balance, microbial dynamics, and safety. Recent solutions include Layer-Structured Membranes (LSMs) and artificial intelligence-driven control, which improve biofilm stability, optimize gas transfer, and ensure long-term performance. Collectively, these advances underscore methane-based MABRs as a promising technology for sustainable and low-carbon wastewater treatment.

RevDate: 2025-09-21

Maric T, Tanaka Y, Li Z, et al (2025)

Micro/nanomotors for biofilm remediation: Nanoarchitectonic breakthroughs with a focus on regulatory and clinical translation challenges.

Biomaterials, 326:123715 pii:S0142-9612(25)00634-9 [Epub ahead of print].

Biofilm-associated bacterial infections, notorious for their resistance to standard therapies, pose a critical challenge in clinical practice. Micro and nanomotors (MNMs) have emerged as dynamic tools capable of penetrating biofilm matrices and enabling targeted antimicrobial delivery through autonomous motion. Recent advances in nanoarchitectonic design, spanning fuel-free or chemical propulsion, biohybrid systems, and multimodal actuation, significantly enhance their therapeutic precision and biocompatibility. This review critically examines the evolution of MNM materials, geometries, and designs, emphasizing their mechanical disruption of extracellular polymeric substances and synergistic bactericidal effects. Innovations such as cascade-driven MNMs and stimuli-responsive platforms demonstrate >90 % biofilm eradication in vitro and accelerated wound healing in vivo. What distinguishes this review from existing literature is its integrated focus on regulatory and translational barriers to clinical adoption, an aspect seldom addressed in prior MNM reviews. In addition to advances in materials and design, we discuss challenges that must be overcome for clinical translation, including long-term biosafety, degradation, scalable manufacturing under Good Manufacturing Practice (GMP), and regulatory ambiguities surrounding nanoscale medical devices. We outline a path forward for addressing these barriers by emphasizing the need for standardized toxicity testing, stronger interdisciplinary collaboration, and the use of emerging regulatory tools such as Safe(r) Innovation Approaches (SIA), the EU's Safe and Sustainable by Design (SSbD) initiative, and regulatory sandboxes to help accelerate clinical translation. By integrating material and design innovation with regulatory foresight, MNM technology holds transformative potential for combating antibiotic-resistant infections and redefining the eradication of biofilms.

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ESP Quick Facts

ESP Origins

In the early 1990's, Robert Robbins was a faculty member at Johns Hopkins, where he directed the informatics core of GDB — the human gene-mapping database of the international human genome project. To share papers with colleagues around the world, he set up a small paper-sharing section on his personal web page. This small project evolved into The Electronic Scholarly Publishing Project.

ESP Support

In 1995, Robbins became the VP/IT of the Fred Hutchinson Cancer Research Center in Seattle, WA. Soon after arriving in Seattle, Robbins secured funding, through the ELSI component of the US Human Genome Project, to create the original ESP.ORG web site, with the formal goal of providing free, world-wide access to the literature of classical genetics.

ESP Rationale

Although the methods of molecular biology can seem almost magical to the uninitiated, the original techniques of classical genetics are readily appreciated by one and all: cross individuals that differ in some inherited trait, collect all of the progeny, score their attributes, and propose mechanisms to explain the patterns of inheritance observed.

ESP Goal

In reading the early works of classical genetics, one is drawn, almost inexorably, into ever more complex models, until molecular explanations begin to seem both necessary and natural. At that point, the tools for understanding genome research are at hand. Assisting readers reach this point was the original goal of The Electronic Scholarly Publishing Project.

ESP Usage

Usage of the site grew rapidly and has remained high. Faculty began to use the site for their assigned readings. Other on-line publishers, ranging from The New York Times to Nature referenced ESP materials in their own publications. Nobel laureates (e.g., Joshua Lederberg) regularly used the site and even wrote to suggest changes and improvements.

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When the site began, no journals were making their early content available in digital format. As a result, ESP was obliged to digitize classic literature before it could be made available. For many important papers — such as Mendel's original paper or the first genetic map — ESP had to produce entirely new typeset versions of the works, if they were to be available in a high-quality format.

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Early support from the DOE component of the Human Genome Project was critically important for getting the ESP project on a firm foundation. Since that funding ended (nearly 20 years ago), the project has been operated as a purely volunteer effort. Anyone wishing to assist in these efforts should send an email to Robbins.

ESP Plans

With the development of methods for adding typeset side notes to PDF files, the ESP project now plans to add annotated versions of some classical papers to its holdings. We also plan to add new reference and pedagogical material. We have already started providing regularly updated, comprehensive bibliographies to the ESP.ORG site.

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This is a must read book for anyone with an interest in invasion biology. The full title of the book lays out the author's premise — The New Wild: Why Invasive Species Will Be Nature's Salvation. Not only is species movement not bad for ecosystems, it is the way that ecosystems respond to perturbation — it is the way ecosystems heal. Even if you are one of those who is absolutely convinced that invasive species are actually "a blight, pollution, an epidemic, or a cancer on nature", you should read this book to clarify your own thinking. True scientific understanding never comes from just interacting with those with whom you already agree. R. Robbins

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Papers in Classical Genetics

The ESP began as an effort to share a handful of key papers from the early days of classical genetics. Now the collection has grown to include hundreds of papers, in full-text format.

Digital Books

Along with papers on classical genetics, ESP offers a collection of full-text digital books, including many works by Darwin and even a collection of poetry — Chicago Poems by Carl Sandburg.

Timelines

ESP now offers a large collection of user-selected side-by-side timelines (e.g., all science vs. all other categories, or arts and culture vs. world history), designed to provide a comparative context for appreciating world events.

Biographies

Biographical information about many key scientists (e.g., Walter Sutton).

Selected Bibliographies

Bibliographies on several topics of potential interest to the ESP community are automatically maintained and generated on the ESP site.

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