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Bibliography on: Biofilm

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ESP: PubMed Auto Bibliography 26 Jan 2020 at 01:33 Created: 


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 pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

RevDate: 2020-01-25

P D, H G G, H P (2020)

Co-occurrence of functionally diverse bacterial community as biofilm on the root surface of Eichhornia crassipes (Mart.) Solms-Laub.

The Science of the total environment, 714:136683 pii:S0048-9697(20)30193-5 [Epub ahead of print].

The current study investigates the functional diversity of bacterial community existing as a biofilm on the root surface of water hyacinth (Eichhornia crassipes (Mart.) Solms-Laub.) grown in Yamuna river, Delhi, India. Forty-nine bacterial isolates recorded a diverse pattern of susceptibility/resistance to 23 antibiotics tested. Most of the bacterial isolates were susceptible to Ofloxacin, Ciprofloxacin, Ceftriaxone, Gentamicin, and Cefepime and resistant to Ceftazidime, Nitrofurantoin, Ampicillin, and Nalidixic acid. Isolate RB33-V recorded resistant against 11 antibiotics tested, and RB42-V was found susceptible to most of the antibiotics tested. Among the seven heavy metals tested, the highest of 39 bacteria showed resistance to zinc, and least of 9 bacteria recorded resistance against cadmium. Isolate RB20-III was susceptible to all heavy metals tested, and RB23-III was found resistance for six heavy metals tested. A higher correlation was observed with zinc and multiple antibiotic resistance, and Ceftazidime resistance was most frequently associated with all the heavy metals tested. These bacteria grow optimally under neutral-alkali conditions and susceptible to acidic conditions, and they can withstand a broad range of temperatures and salt concentrations. They are very poor in phosphate solubilization. Further, the bacteria recorded varied results for beneficial traits, hemolytic, and DNase activity. The results of bacterial characterization indicated that this bacterial community is of multi-origin in nature and are assisting the host-plant in withstanding the adverse and fluctuating conditions of the Yamuna river by reducing the toxic effect of heavy metals, antibiotics and other xenobiotics.

RevDate: 2020-01-25

Liu L, Xiao X, Li K, et al (2020)

Synthesis of catechin-rare earth complex with efficient and broad-spectrum anti-biofilm activity.

Chemistry & biodiversity [Epub ahead of print].

Biofilm is the crucial reason of clinical infections. Herein, green tea based polyphenol (catechin) and rare earth (Re) metal ions were employed for the preparation of catechin-Re complexes with significant anti-biofilm properties. The complexes were characterized by FT-IR, raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS), which suggested that catechin coordinated with Re 3+ through its ortho phenolic hydroxyl groups. The prepared catechin-Re showed significant effects in anti-biofilm growth against P. aeruginosa (gram-negative bacteria), S. sciuri (gram-positive bacteria), and A. niger (fungus), which significantly exceeded the utilization of catechin or Re 3+ . Morphological observations indicated that catechin supplied cell affinity to transfer Re 3+ and helped to damage cell membrane, which act as a carrier to exert cytotoxicity of Re 3+ to realize anti-biofilm. Differential gene expression analysis described gene expression changes induced by catechin-Re, including 56, 272 and 2160 downregulated genes for P. aeruginosa , S. sciuri and A. niger , respectively, which suggested critical changes in cellular metabolism, growth and other processes. These results illustrate the outstanding superiority of catechin-Re complexes in anti-infection aspect-that is, the green tea based rare earth complexes are promising candidates for anti-biofilm applications to address serious challenges in the prevention of multiple infections.

RevDate: 2020-01-25

Tziourrou P, Vakros J, HK Karapanagioti (2020)

Using diffuse reflectance spectroscopy (DRS) technique for studying biofilm formation on LDPE and PET surfaces: laboratory and field experiments.

Environmental science and pollution research international pii:10.1007/s11356-020-07729-0 [Epub ahead of print].

Biofilm formation on plastic debris needs to be further investigated, because microorganisms attached to plastics are transferred in all three dimensions to new regions by ocean currents. The current study aims to investigate biofilm formation on plastic strips in aquatic ecosystems using a simple physicochemical method commonly used to characterize solid surfaces, namely, the diffuse reflectance UV-Vis spectroscopy (DRS) method. Using virgin polymers that have not being exposed to the environment as a reference, DRS peaks can be attributed to the microorganisms attached to the polymer surface with time. The polymers tested were light-density polyethylene (LDPE) and polyethylene terephthalate (PET). For LDPE strips for all sampling times in the field, the development of the peaks among 10 similar samples was rather uniform in terms of peak wavelength with time. For PET strips during the early sampling time, the development of the peaks among 10 similar samples was rather uniform in terms of peak wavelength but varied in terms of intensity. This last observation phased out with longer exposure times that the peaks had similar distribution in terms of peak wavelength and intensity. Similar experiments were run for longer exposure times both in an oligotrophic laboratory bioreactor and in the marine environment. In both cases, the biofilm on PET samples seems to reach a steady state faster than LDPE with similar peaks found on both samples DRS proved to be a robust and useful tool to study the formation of biofilm on plastic samples without any pretreatment and without sample destruction. Graphical abstract.

RevDate: 2020-01-25

Salgar-Chaparro SJ, Lepkova K, Pojtanabuntoeng T, et al (2020)

Nutrient level determines biofilm characteristics and the subsequent impact on microbial corrosion and biocide effectiveness.

Applied and environmental microbiology pii:AEM.02885-19 [Epub ahead of print].

The impact that nutrient level has on biofilm characteristics, biocide effectiveness and the associated risk of microbiologically influenced corrosion (MIC) was assessed using multispecies biofilms from two different oilfield consortia. A range of microbiological, microscopy and corrosion methods demonstrated that the continuous flow of nutrients for the microbial growth resulted in higher activity, thickness and robustness of the biofilms formed on carbon steel, which induced greater localised corrosion compared to biofilms formed under batch, nutrient-depleted conditions. Despite of the differences in biofilms characteristics, biofilms displayed comparable susceptibility to glutaraldehyde biocide with similar log10 reduction and percent reduction of microorganisms in both nutrient conditions. Nevertheless, nutrient replenishment impacted the effectiveness of the biocide in controlling microbial populations; a higher concentration of cells survived the biocide treatment in biofilms formed under a continuous flow of nutrients. Complementary DNA and RNA-based amplicon sequencing and bioinformatics analysis were used to discriminate the active within the total populations in biofilms established at the different nutrient conditions and allowed the identification of the microbial species that remained active despite nutrient depletion and biocide treatment. Detection of persistent active microorganisms after exposure to glutaraldehyde, regardless of biofilm structure, suggested the presence of microorganisms less susceptible to this biocide and highlighted the importance of monitoring active microbial species for the early detection of biocide resistance in oil production facilities.Importance Microbiologically influenced corrosion (MIC) is a complex process that generates economic losses to the industry every year. Corrosion must be managed to prevent a loss of containment of produced fluids to the external environment. MIC Management includes the identification of assets with higher MIC risk, which could be influenced by nutrient levels in the system. Assessing biofilms under different nutrient conditions is essential for understanding the impact of flow regime on microbial communities and the subsequent impact on microbial corrosion and on the effectiveness of biocide treatment. This investigation simulates closely oil production systems, which contain piping sections exposed to continuous flow and sections that remain stagnant for long periods. Therefore, results reported here are useful for MIC management and prevention. Moreover, the complementary methodological approach applied in this investigation highlighted the importance of implementing RNA-based methods for better identification of active microorganisms that survive stress conditions in oil systems.

RevDate: 2020-01-24

Soliman MYM, van Halem D, G Medema (2019)

Virus removal by ceramic pot filter disks: Effect of biofilm growth and surface cleaning.

International journal of hygiene and environmental health, 224:113438 pii:S1438-4639(19)30715-1 [Epub ahead of print].

Ceramic pot filters are household water treatment and safe storage (HWTS) systems designed to improve the microbial quality of drinking water. They yield high log reduction values (LRVs) for bacterial and protozoan pathogens but provide very little removal of viruses. This study investigated virus removal of ceramic filter discs (CFDs), using feed water with 3 different nutrient levels under extended continuous operation and limited cleaning frequency. The results show that filter use without cleaning resulted in biofilm growth and MS2 LRV values increased with increasing feed water nutrient content. Cleaning the filter surface by scrubbing led to a partial or total loss in improved LRVs, indicating the importance of this biological top layer to the removal of MS2. Overall, the removal capacity of a matured biofilm remained constant, regardless of its age. MS2 LRVs ranged between 0.9 ± 0.2 LRV for low nutrient (LN), 1.6 ± 0.2 LRV for medium nutrient (MN) and 2.4 ± 0.5 LRV for high nutrient (HN) biofilms. Interestingly, a change in feed conditions for the HN filters resulted in an unprecedented high LRV of >4 LRV, which supports further investigation of the mechanistic role of biofilms in virus removal.

RevDate: 2020-01-24

Karballaei Mirzahosseini H, Hadadi-Fishani M, Morshedi K, et al (2020)

Meta-Analysis of Biofilm Formation, Antibiotic Resistance Pattern, and Biofilm-Related Genes in Pseudomonas aeruginosa Isolated from Clinical Samples.

Microbial drug resistance (Larchmont, N.Y.) [Epub ahead of print].

Resistant microorganisms such as Pseudomonas aeruginosa grow by developing biofilms in hospitals. We aimed to investigate the biofilm formation and the frequencies of biofilm-related genes and their associations with antibiotic resistance pattern in P. aeruginosa isolated from Iranians' clinical samples. This review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We conducted a systematic literature search in scientific databases using medical subject heading terms, including "Pseudomonas aeruginosa," "biofilm formation," "biofilm-related genes," "antibiotic resistance," and "prevalence," to obtain related articles published from 1st January, 2000, to 30th March, 2019. The studies reporting the prevalence of biofilm formation, the frequencies of biofilm-related genes, and the antibiotic resistance pattern in P. aeruginosa retrieved from Iranian patients were included. Meta-analysis was performed using the Comprehensive Meta-Analysis software. The pooled rate of biofilm formation was calculated as 86.5% (95% confidence interval [CI]: 79-91.6). The combined frequencies of strong, moderate, and weak biofilms were 51% (95% CI: 37.4-64.4), 29.2% (95% CI: 20.9-39.1), and 25.4% (95% CI: 11.5-47.2), respectively. The pooled prevalence of laslR, algD, algU, ppyR, and pelF genes were 93.6% (95% CI: 88.1-96.6), 91.4% (95% CI: 80.8-96.4), 89.3% (95% CI: 85.2-92.3), 98.7% (95% CI: 96.5-99.6), and 93% (95% CI: 82.7-97.3), respectively. The highest combined antibiotic resistance rates of P. aeruginosa isolates were against piperacillin/tazobactam (90%). This study showed that biofilm formation was higher in multidrug-resistant (MDR) P. aeruginosa than non-MDRs. A significant correlation was observed between biofilm formation and antibiotic resistance in 50% of studies included in this review.

RevDate: 2020-01-24

Vargas-Cruz N, Rosenblatt J, Reitzel RA, et al (2019)

Pilot Ex Vivo and In Vitro Evaluation of a Novel Foley Catheter with Antimicrobial Periurethral Irrigation for Prevention of Extraluminal Biofilm Colonization Leading to Catheter-Associated Urinary Tract Infections (CAUTIs).

BioMed research international, 2019:2869039.

CAUTI remains a serious healthcare issue for incontinent patients whose urine drainage is managed by catheters. A novel double-balloon Foley catheter was developed which was capable of irrigating the extraluminal catheter surfaces within the periurethral space between the urethral-bladder junction and meatus. The catheter has a retention cuff that is inflated to secure the catheter in the bladder and a novel irrigation cuff proximal to the urethral-bladder junction capable of providing periurethral irrigation from the urethral-bladder junction to the meatus. Uniform periurethral irrigation was demonstrated in an ex vivo porcine model by adding a dye to the antimicrobial urethral irrigation solution. An in vitro biofilm colonization model was adapted to study the ability of periurethral irrigation with a newly developed antimicrobial combination consisting of polygalacturonic acid + caprylic acid (PG + CAP) to prevent axial colonization of the extraluminal urethral indwelling catheter shaft by common uropathogens. The extraluminal surface of control catheters that were not irrigated formed biofilms along the entire axial urethral tract after 24 hours. Significant (p < 0.001) inhibition of colonization was seen against multidrug-resistant Pseudomonas aeruginosa (PA), carbapenem-resistant Escherichia coli (EC), and carbapenem-resistant Klebsiella pneumoniae (KB). For other common uropathogens including Candida albicans (CA), Proteus mirabilis (PR), and Enterococcus faecalis (EF), a first irrigation treatment completely inhibited colonization of half of the indwelling catheter closest to the bladder and a second treatment largely disinfected the remaining intraurethral portion of the catheter towards the meatus. The novel Foley catheter and PG + CAP antimicrobial irrigant prevented biofilm colonization in an in vitro CAUTI model and merits further testing in an in vivo CAUTI prevention model.

RevDate: 2020-01-24

Shemesh M, I Ostrov (2020)

Role of Bacillus species in biofilm persistence and emerging antibiofilm strategies in the dairy industry.

Journal of the science of food and agriculture [Epub ahead of print].

Biofilm-forming Bacillus species are often involved in persistent contamination and spoilage of dairy products. Therefore, they present a major microbiological challenge in the field of dairy food quality and safety. Due to a vast physiological versatility, Bacillus species can survive in various sections of dairy manufacturing plants, leading to high risk in product spoilage and potential dissemination of foodborne diseases. Furthermore, biofilm and heat-resistant spore formation make these bacteria challenging to eliminate. Thus, some strategies have been employed to remove, prevent, or delay the formation of Bacillus biofilms in the dairy industry, but with limited success. Lack of understanding in the Bacillus biofilm structure and behavior in conditions relevant to dairy-associated environments could partially account for this situation. Current paper reviews dairy-associated biofilm formation by Bacillus species, with particular attention to the role of biofilm in Bacillus species adaptation and survival in a dairy processing environment. Besides, relevant model systems are discussed for developing novel antimicrobial approaches to improve the quality of dairy food. This article is protected by copyright. All rights reserved.

RevDate: 2020-01-24

Tang T, Chen G, Guo A, et al (2020)

Comparative proteomic and genomic analyses of Brucella abortus biofilm and planktonic cells.

Molecular medicine reports, 21(2):731-743.

The present study aimed to explore the differences in protein and gene expression of Brucella abortus cultured under biofilm and planktonic conditions. The proteins unique to biofilms and planktonic B. abortus were separated by two‑dimensional (2‑D) electrophoresis and then identified by matrix‑assisted laser desorption/ionization‑tandem time of flight‑mass spectrometry (MALDI‑TOF/TOF‑MS). High‑throughput sequencing and bioinformatic analyses were performed to identify differentially expressed genes between B. abortus cultured under biofilm and planktonic conditions. The proteins and genes identified by proteomic and genomic analyses were further evaluated via western blot and reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analyses. 2‑D electrophoresis identified 20 differentially expressed protein spots between biofilms and planktonic cells, which corresponded to 18 individual proteins (12 downregulated and 6 upregulated) after MALDI‑TOF/TOF‑MS analysis, including elongation factor Tu and enolase. RT‑qPCR analysis revealed that all of the 18 genes were downregulated in biofilms compared with planktonic cells. Western blot analysis identified 9 downregulated and 3 upregulated proteins. High‑throughput sequencing and bioinformatic analyses identified 14 function and pathway‑associated genes (e.g., BAbS19_I14970). RT‑qPCR analysis of the 14 genes showed that they were upregulated in biofilm compared with in planktonic state. In conclusion, these differentially expressed genes may play important roles in bacterial defense, colonization, invasion, and virulence.

RevDate: 2020-01-24

Adoonsook D, Chia-Yuan C, Wongrueng A, et al (2020)

Microbial Community Composition in Different Carbon Source Types of Biofilm A/O-MBR Systems with Complete Sludge Retention.

Environmental technology [Epub ahead of print].

In this study, the three biofilm-anoxic-oxic-MBR systems were operated in parallel using different carbon source feed types. The three systems were operated with complete sludge retention to compare microbial community composition and system efficiency. High average removal of ammonia and COD was obtained in the three reactors. However, total nitrogen and total phosphorus removal efficiency were significantly higher in the VFAs feed systems when compared with the glucose feed system. The highest and most stable BNR efficiency was observed when acetate was used as a carbon source. The qPCR analysis revealed that ammonium oxidizing bacteria, denitrifiers and total bacteria were all highest in the acetate feed system followed by the propionate feed system. Moreover, among all carbon source types, the PUS-biofilm could maintain a higher degree of abundance of total bacteria than the sludge biomass. Meanwhile, ammonium oxidizing bacteria and denitrifiers were enriched in the sludge biomass rather than in the PUS-biofilm. The results of illumina sequencing revealed that acetate followed by propionate were favorable to the growth of microorganisms that were associated with the BNR process, which was the main reason for the high efficiency of nutrient removal in the acetate and propionate feed systems.

RevDate: 2020-01-24

Liang X, Zhang XK, Peng LH, et al (2020)

The Flagellar Gene Regulates Biofilm Formation and Mussel Larval Settlement and Metamorphosis.

International journal of molecular sciences, 21(3): pii:ijms21030710.

Biofilms are critical components of most marine systems and provide biochemical cues that can significantly impact overall community composition. Although progress has been made in the bacteria-animal interaction, the molecular basis of modulation of settlement and metamorphosis in most marine animals by bacteria is poorly understood. Here, Pseudoalteromonasmarina showing inducing activity on mussel settlement and metamorphosis was chosen as a model to clarify the mechanism that regulates the bacteria-mussel interaction. We constructed a flagellin synthetic protein gene fliP deletion mutant of P. marina and checked whether deficiency of fliP gene will impact inducing activity, motility, and extracellular polymeric substances of biofilms. Furthermore, we examined the effect of flagellar proteins extracted from bacteria on larval settlement and metamorphosis. The deletion of the fliP gene caused the loss of the flagella structure and motility of the ∆fliP strain. Deficiency of the fliP gene promoted the biofilm formation and changed biofilm matrix by reducing β-polysaccharides and increasing extracellular proteins and finally reduced biofilm-inducing activities. Flagellar protein extract promoted mussel metamorphosis, and ∆fliP biofilms combined with additional flagellar proteins induced similar settlement and metamorphosis rate compared to that of the wild-type strain. These findings provide novel insight on the molecular interactions between bacteria and mussels.

RevDate: 2020-01-23

Garcia D, Mayfield CK, Leong J, et al (2020)

Early Adherence and Biofilm Formation of Cutibacterium acnes (formerly Propionibacterium acnes) On Spinal Implant Materials.

The spine journal : official journal of the North American Spine Society pii:S1529-9430(20)30001-2 [Epub ahead of print].

BACKGROUND: Cutibacterium acnes (C. acnes) is associated with infection following shoulder and spine surgery due to follicular pore concentrations in these anatomic regions. It has been established that it can form biofilms on surgical implant materials, which may contribute to its role in perioperative infection, but its behavior of early colonization on those materials is not yet well understood.

PURPOSE: The purpose of this study was to evaluate the time to adherence and subsequent biofilm formation of C. acnes in the first 24 hours on implant materials commonly used in spinal surgery.

STUDY DESIGN: We compared the colonization and behavior of C. acnes over time when applied to 5 commonly used spine implant materials: polyether ether ketone (PEEK), cobalt chromium (CC), stainless steel (SS), titanium (Ti), and titanium alloy (TiA).

METHODS: C. acnes was applied onto samples of PEEK, CC, SS, Ti, and TiA, and allowed to adhere for periods of 4, 8, 12, 16, and 20 hours. Nonadherent bacteria were then washed from the samples. These samples were then allowed to continue incubating for a total 24 hours. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to visualize all samples for the presence and quantification of C. acnes adherence at each time period. Subsequent transition to biofilm formation on these samples was assessed via SEM at each time period.

RESULTS: The PEEK specimens exhibited the highest amount of surface biological burden in the first 24 hours compared to the other materials, which displayed little or no adherence. Rapid biofilm formation first observed at 8 hours of allowed adhesion on PEEK, whereas no significant biofilm formation was seen on the other materials during the observed time period.

CONCLUSIONS: Although C. acnes is known to have a slow proliferation rate, the results of this investigation demonstrate that it can rapidly adhere to and form biofilm on PEEK. These data suggest that the use of PEEK implants placed during spinal surgery may facilitate early intraoperative colonization, and subsequent infection, compared to metallic implants.

CLINICAL SIGNIFICANCE: The findings of this study suggest that PEEK may prove to be problematic as a choice of implant material in cases were C. acnes infection is a possibility.

RevDate: 2020-01-23

Vaezi SS, Poorazizi E, Tahmourespour A, et al (2020)

Application of artificial neural networks to describe the combined effect of pH, time, NaCl and ethanol concentrations on the biofilm formation of Staphylococcus aureus.

Microbial pathogenesis pii:S0882-4010(19)32070-4 [Epub ahead of print].

Biofilms are organized communities, adherent to the surface and resistant to adverse environmental and antimicrobial agents. So, its control is very important. Staphylococcus aureus is an opportunistic pathogen with the biofilm-forming ability that causes numerous problems in the medicine and food industry. Therefore, this study aimed to investigate the effect of pH, ethanol and NaCl concentrations after 24 and 48 h incubation times at 37 °C, also modeling the results with artificial neural network (ANN). For this purpose, after both incubation times, the effect of each parameter was studied, separately and also in combination at the levels in which the highest biofilm was formed. All results were modeled using multiple ANN and compared in terms of R-value and MSE. The highest biofilm formation ability was in neutral pH. Adding the ethanol and NaCl stimulated biofilm formation, but the inhibitory effect was observed at high concentrations of ethanol and NaCl and very acidic or highly alkaline pH levels. The more incubation time also led to an increase in biofilm formation. Eventually, the Feed-Forward, Back-Propagation Neural Network model with the Levenberg-Marquardt training algorithm and 4-12-1 topology was chosen (R-value = 0.995 and validation MSE = 0.011467). This ANN had high modeling ability because there was a high correlation between experimental data and modeling data. Therefore, it was concluded that pH, ethanol, NaCl, and time are effective parameters in the biofilm formation and there is a nonlinear relationship between these factors that the ANN is capable of modeling them.

RevDate: 2020-01-23

Furuichi Y, Yoshimoto S, Inaba T, et al (2020)

Process description of an unconventional biofilm formation by bacterial cells autoagglutinating through sticky, long, and peritrichate nanofibers.

Environmental science & technology [Epub ahead of print].

In this study, we elucidated the formation process of an unconventional biofilm formed by a bacterium autoagglutinating through sticky, long, and peritrichate nanofibers. Understanding the mechanisms of biofilm formation is essential to control microbial behavior and improve environmental biotechnologies. Acinetobacter sp. Tol 5 autoagglutinate through the interaction of the long, peritrichate nanofiber protein AtaA, a trimeric autotransporter adhesin. Using AtaA, without cell growth or extracellular polymeric substances production, Tol 5 cells quickly form an unconventional biofilm. The process forming this unconventional biofilm started with cell-cell interactions, proceeded to cell clumping, and led to the formation of large cell aggregates. The cell-cell interaction was described by DLVO theory based on a new concept, which considers two independent interactions between two cell bodies and between two AtaA fiber tips forming a discontinuous surface. If cell bodies cannot collide owing to an energy barrier at low ionic strengths but approach within the interactive distance of AtaA fibers, cells can agglutinate through their contact. Cell clumping proceeds following the cluster-cluster aggregation model, and an unconventional biofilm containing void spaces and a fractal nature develops. Understanding its formation process would extend the utilization of various types of biofilms, enhancing environmental biotechnologies.

RevDate: 2020-01-23

Wu J, Fan Y, Wang X, et al (2020)

Effects of the natural compound, oxyresveratrol, on the growth of Streptococcus mutans, and on biofilm formation, acid production, and virulence gene expression.

European journal of oral sciences [Epub ahead of print].

Streptococcus mutans is one of the major pathogens of dental caries. Oxyresveratrol, a natural compound found in plants, exerts inhibitory effects on many bacterial species but its effect on S. mutans is unknown. The objective of this study was to clarify the antibacterial effect of oxyresveratrol on S. mutans, including effects on basic viability, acidogenicity, acidurity, and extracellular polysaccharide synthesis. The expression of nine genes that encode virulence and protective factors in S. mutans was measured by qRT-PCR. Oxyresveratrol showed a dose-dependent inhibitory effect on survival of S. mutans. At 250 μg ml-1 , oxyresveratrol reduced the S. mutans survival rate, inhibited synthesis of water-insoluble glucans, compromised biofilm formation, and significantly down-regulated the expression of glucosyltransferase-I (gtfB) and glucosyltransferase-SI (gtfC). However, the enzymatic activity of lactate dehydrogenase protein was increased and the expression of lactate dehydrogenase (ldh) and ATP synthase subunit beta (atpD) genes were also up-regulated. Besides, glucosyltransferase S (gtfD) up-regulation indicated that water-soluble glucan synthesis was promoted. The vicR, liaR, and comDE genes, which exert a self-protective function in response to external stress, were also up-regulated. In conclusion, oxyresveratrol inhibited the growth of S. mutans and also reduced biofilm formation, acid production, and synthesis of water-insoluble glucans by this organism. In addition, oxyresveratrol also activated a series of S. mutans self-protection mechanisms.

RevDate: 2020-01-23

Khan F, Pham DTN, YM Kim (2020)

Alternative strategies for the application of aminoglycoside antibiotics against the biofilm-forming human pathogenic bacteria.

Applied microbiology and biotechnology pii:10.1007/s00253-020-10360-1 [Epub ahead of print].

Aminoglycosides are one of the common classes of antibiotics that have been widely used for treating infections caused by pathogenic bacteria. The mechanism of bactericidal action by aminoglycosides is well-known, by which it terminates the cytoplasmic protein synthesis. However, the potentials of aminoglycosides become hindered when facing the evolution of bacterial resistance mechanisms. Among multiple resistance mechanisms displayed by bacteria against antibiotics, the formation of biofilm is the mechanism that provides a barrier for antibiotics to reach the cellular level. Bacteria present in the biofilm also get protection against the impact of host immune responses, harsh environmental conditions, and other antimicrobial treatments. Hence, with the multifaceted resistance developed by biofilm-forming pathogenic bacteria, antibiotics are therefore discontinued for further applications. However, the recent research developed several alternative strategies such as optimization of the active concentration, modification of the environmental conditions, modification of the chemical structure, combinatorial application with other active agents, and formulation with biocompatible carrier materials to revitalize and exploit the new potential of aminoglycosides. The present review article describes the above mentioned multiple approaches and possible mechanisms for the application of aminoglycosides to treat biofilm-associated infections.

RevDate: 2020-01-23

Caro-Astorga J, Frenzel E, Perkins JR, et al (2020)

Biofilm formation displays intrinsic offensive and defensive features of Bacillus cereus.

NPJ biofilms and microbiomes, 6:3 pii:112.

Biofilm formation is a strategy of many bacterial species to adapt to a variety of stresses and has become a part of infections, contaminations, or beneficial interactions. In this study, we demonstrate that profound physiological changes permit Bacillus cereus to switch from a floating to a sessile lifestyle, to undergo further maturation of the biofilm and to differentiate into the offensive or defensive features. We report that floating and biofilm cells are populations that differentiate metabolically, with members of each subpopulation developing different branches of certain metabolic pathways. Secondly, biofilm populations rearrange nucleotides, sugars, amino acids, and energy metabolism. Thirdly, this metabolic rearrangement coexists with: the synthesis of the extracellular matrix, sporulation, reinforcement of the cell wall, activation of the ROS detoxification machinery and production of secondary metabolites. This strategy contributes to defend biofilm cells from competitors. However, floating cells maintain a fermentative metabolic status that ensures a higher aggressiveness against hosts, evidenced by the production of toxins. The maintenance of the two distinct subpopulations is an effective strategy to face different environmental conditions found in the life styles of B. cereus.

RevDate: 2020-01-23

Uppuluri P (2020)

Candida auris Biofilm Colonization on Skin Niche Conditions.

mSphere, 5(1): pii:5/1/e00972-19.

Candida auris, an emerging multidrug-resistant yeast, has recently been associated with outbreaks of invasive infections in health care facilities worldwide. Its success as a nosocomial pathogen lies in its capability to sustain for prolonged periods in the intensive care unit (ICU), adeptly colonize skin, and spread among patients. Little is known of the mechanism behind the predilection of C. auris for skin or the extent of its resilience on it. Now, M. V. Horton, C. J. Johnson, J. F. Kernien, T. D. Patel, et al. (mSphere 5:e00910-19, 2020, demonstrate that in synthetic sweat medium designed to mimic axillary skin conditions, C. auris can grow into multilayers of cells called biofilms that can resist desiccation. C. auris' propensity to form biofilms was further elaborated using a novel ex vivo porcine skin model of skin colonization. These studies provide early evidence that C. auris biofilm cells persisting on skin could serve as source of continuing outbreaks in health care facilities. Interventions blocking C. auris biofilm growth on skin will help control the spread of this pathogen.

RevDate: 2020-01-23

Kumar A, Gahlyan S, Thakur R, et al (2020)

Synthesis of Mesoporous SBA-16 and SBA-16/ZnO₂ Nano-Composite Thin Film for Anti-Biofilm Application.

Journal of nanoscience and nanotechnology, 20(7):4210-4215.

SBA-16 is a mesoporous nanostructure with high surface area and cubic symmetry which make them an ideal carrier to carry different nanoparticles. Zinc peroxide (ZnO₂) is a novel nanoparticle that inhibits the growth of microorganisms due to its antiseptic property. Thin film of SBA-16 and SBA-16/ZnO₂ was deposited on glass slide by spin coating method. Anti-biofilm property of the thin films was examined against E. coli and S. aureus bacteria. Structural property was found out by wide angle X-ray diffraction (XRD), small angle X-ray scattering (SAXS) and High Resolution Transmission Electron Microscope (HRTEM). Fourier Transform Infrared Spectrophotometer (FTIR) was used to confirmation the presence of ZnO₂ in Nano-composite and AFM utilized for surface topography of thin films. Fluorescent microscope image clearly revealed that SBA-16/ZnO₂ nanocomposite thin film significantly inhibit the biofilm formation against both E. coli (gram negative bacteria) as well as S. aureus (gram positive bacteria) in comparision to SBA-16. The antimicrobial behavior of ZnO nanoparticle is due to formation of H₂O₂ as reactive oxygen species (ROS) to which the bacterial cells are permeable. H₂O₂ is a powerful oxidizing agents that oxidized the mycobacterial elements like DNA and proteins which results into the toxicity of the bacteria cell.

RevDate: 2020-01-22

Baddal B (2020)

Characterization of biofilm formation and induction of apoptotic DNA fragmentation by nontypeable Haemophilus influenzae on polarized human airway epithelial cells.

Microbial pathogenesis pii:S0882-4010(19)31700-0 [Epub ahead of print].

Nontypeable Haemophilus influenzae (NTHi) is a common airway commensal and opportunistic pathogen that persists within biofilm communities in vivo. Biofilm studies so far are mainly based on assays on plastic surfaces. The aim of this work was to investigate the capacity of clinical NTHi strains to form biofilm structures on polarized Calu-3 human airway epithelial cells and primary normal human bronchial epithelial cells and to characterize the biofilm architecture. Formation of adherent NTHi biofilms post colonization of host cells at multiple time-points was evaluated using confocal laser scanning microscopy and electron microscopy. NTHi biofilms were analyzed in terms of biofilm height and presence of extracellular matrix components, and their apoptotic effects on epithelial cells was measured by TUNEL assay. Strain Fi176 was observed to form robust biofilms on airway epithelia over time, while disrupting the integrity of Calu-3 monolayer by 72 h of co-culture. NTHi biofilms were observed to induce apoptotic DNA fragmentation in host cells at 24 h post infection. Biofilm formation on cell monolayers by Fi176ΔpilA strain was markedly reduced compared to WT strain. Biofilm inhibition and disruption assays by crystal violet staining indicated that DNA and proteins are part of NTHi biofilms in vitro. Our findings highlight critical stages of NTHi pathogenesis following host colonization and provide useful biofilm models for future antimicrobial drug discovery investigations.

RevDate: 2020-01-22

Nott MA, Driscoll HE, Takeda M, et al (2020)

Advanced biofilm analysis in streams receiving organic deicer runoff.

PloS one, 15(1):e0227567 pii:PONE-D-19-14510.

Prolific heterotrophic biofilm growth is a common occurrence in airport receiving streams containing deicers and anti-icers, which are composed of low-molecular weight organic compounds. This study investigated biofilm spatiotemporal patterns and responses to concurrent and antecedent (i.e., preceding biofilm sampling) environmental conditions at stream sites upstream and downstream from Milwaukee Mitchell International Airport in Milwaukee, Wisconsin, during two deicing seasons (2009-2010; 2010-2011). Biofilm abundance and community composition were investigated along spatial and temporal gradients using field surveys and microarray analyses, respectively. Given the recognized role of Sphaerotilus in organically enriched environments, additional analyses were pursued to specifically characterize its abundance: a consensus sthA sequence was determined via comparison of whole metagenome sequences with a previously identified sthA sequence, the primers developed for this gene were used to characterize relative Sphaerotilus abundance using quantitative real-time PCR, and a Sphaerotilus strain was isolated to validate the determined sthA sequence. Results indicated that biofilm abundance was stimulated by elevated antecedent chemical oxygen demand concentrations, a surrogate for deicer concentrations, with minimal biofilm volumes observed when antecedent chemical oxygen demand concentrations remained below 48 mg/L. Biofilms were composed of diverse communities (including sheathed bacterium Thiothrix) whose composition appeared to shift in relation to antecedent temperature and chemical oxygen demand. The relative abundance of sthA correlated most strongly with heterotrophic biofilm volume (positive) and dissolved oxygen (negative), indicating that Sphaerotilus was likely a consistent biofilm member and thrived under low oxygen conditions. Additional investigations identified the isolate as a new strain of Sphaerotilus montanus (strain KMKE) able to use deicer components as carbon sources and found that stream dissolved oxygen concentrations related inversely to biofilm volume as well as to antecedent temperature and chemical oxygen demand. The airport setting provides insight into potential consequences of widescale adoption of organic deicers for roadway deicing.

RevDate: 2020-01-22

Al Moaleem MM, Porwal A, Al Ahmari NM, et al (2020)

Oral Biofilm on Dental Materials among Khat Chewers.

Current pharmaceutical biotechnology pii:CPB-EPUB-103801 [Epub ahead of print].

BACKGROUND: Nowadays khat chewing habit is increasing among population in southern part of Saudi Arabia, Jazan and till date there is no literature investigating the effect of khat on oral biofilm on dental materials.

AIM OF THE STUDY: To evaluate and compare the bacterial biofilm on different types of dental restorative materials used in replacing missing tooth structures among khat chewers and non-khat chewers.

MATERIALS AND METHODS: Hundred twenty biofilm samples were collected from different dental restorations such as All-ceramic (AL), metal ceramic (MC), metal crowns or bridges (M), composite (C), glass ionomer (GI) and amalgam (A) restorations in non-khat and khat chewers (K). DNA extraction was done and subjected to PCR. Bacterial species such as Streptococcus, Neisseria, Bacillus, Granulicatella and Veillonella were identified and counted. PCR products were also sequenced to detect similarity. Association between bacterial type and dental materials among non-khat and khat chewers were tested with Chi-Square test (Fishers Exact test).

RESULTS: The frequency and percentage of Streptococcus species was marginally higher among khat chewers (42; 70%) comparing with non-khat chewers (38; 63.3%) group. But the Veillonella species were higher among non-khat chewers (9: 15%), compared to the khat chewers group (7; 11.7%). No statistically significant difference was detected among species in both groups. In non-khat and khat chewer group, the maximum hits were related to Streptococcus spp in glass inomer, amalgam, and composite (restorative materials), followed by metal ceramic and metal (prosthetic materials). Veillonella spp showed maximum hits in metal group among non-khat chewers and in all-ceramic among khat chewers. Statically significant differences were recorded among composite and amalgam samples with p values 0.047 and 0.036 in khat chewer group.

CONCLUSION: Khat have a statistically significant differences on oral biofilm in the composite and amalgam restorative materials, but there were no significant differences found among any materials and species between the groups.

RevDate: 2020-01-22

Kurmoo Y, Hook AL, Harvey D, et al (2020)

Real time monitoring of biofilm formation on coated medical devices for the reduction and interception of bacterial infections.

Biomaterials science [Epub ahead of print].

Real time monitoring of bacterial attachment to medical devices provides opportunities to detect early biofilm formation and instigate appropriate interventions before infection develops. This study utilises long period grating (LPG) optical fibre sensors, incorporated into the lumen of endotracheal tubes (ETTs), to monitor in real time, Pseudomonas aeruginosa surface colonisation and biofilm formation. The wavelength shift of LPG attenuation bands was monitored for 24 h and compared with biofilm biomass, quantified using confocal fluorescence microscopy imaging. Biofilm formation was compared on uncoated ETTs and optical fibres, and on a biofilm resistant acrylate polymer, after challenge in an artificial sputum or minimal growth medium (RPMI-1640). The LPG sensor was able to detect a biofilm biomass as low as 81 μg cm-2, by comparison with the confocal image quantification. An empirical exponential function was found to link the optical attenuation wavelength shift with the inverse of the biofilm biomass, allowing quantification of biofouling from the spectral response. Quantification from the sensor allows infection interception and early device removal, to reduce, for example, the risk of ventilator associated pneumonia.

RevDate: 2020-01-22

Hsu CY, Cairns L, Hobley L, et al (2020)

Genomic differences between Listeria monocytogenes EGDe isolates reveals crucial roles for SigB and wall rhamnosylation in biofilm formation.

Journal of bacteriology pii:JB.00692-19 [Epub ahead of print].

Listeria monocytogenes is a Gram-positive Firmicute that causes food-borne infections, in part due to its ability to use multiple strategies, including biofilm formation, to survive adverse growth conditions. As a potential way to screen for genes required for biofilm formation we harnessed the ability of bacteria to accumulate mutations in the genome over time, diverging the properties of seemingly identical strains. By sequencing the genomes of four laboratory reference strains of the commonly used L. monocytogenes EGDe, we showed that each isolate contains SNPs compared with the reference genome. We discovered that two SNPs, contained in two independent genes within one of the isolates, impacted biofilm formation. Using bacterial genetics and phenotypic assays, we confirmed that rsbU and rmlA influence biofilm formation. RsbU is the upstream regulator of the alternative sigma factor, SigB and mutation of either rsbU or sigB increased biofilm formation. In contrast, deletion of rmlA, which encodes the first enzyme for TDP-L-rhamnose biosynthesis, resulted in a reduction in the amount of biofilm formed. Further analysis of biofilm formation in a strain that still produces TDP-L-rhamnose, but which cannot decorate the wall teichoic acid with rhamnose (rmlT mutant), showed that it is the decorated wall teichoic acid that is required for adhesion of the cells to surfaces. Together these data uncover novel routes by which biofilm formation by L. monocytogenes can be impacted.Importance Biofilms are an important mode of growth in many settings. Here we have looked at small differences in the genomes of the bacteria Listeria monocytogenes isolate EGDe and used them to find out how biofilms form. This is important fundamental information may help new treatments to be developed and also highlights the fact that isolates of the same identity often diverge.

RevDate: 2020-01-22

Alumutairi L, Yu B, Filka M, et al (2020)

Mild magnetic nanoparticle hyperthermia enhances the susceptibility of Staphylococcus aureus biofilm to antibiotics.

International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group, 37(1):66-75.

Objective: A critical challenge in the treatment of biofilm infection is the capacity of biofilm-grown bacteria to develop resistance to traditional antimicrobial therapies. The objective of this study was to validate the therapeutic potential of magnetic nanoparticle/alternating magnetic field (MNP/AMF) hyperthermia in combination with conventional antibiotics against biofilm infection.Materials and methods: The impact of MNP/AMF hyperthermia on the viability of S. aureus biofilm in the absence and presence of antibiotics as well as on the bactericidal activity of macrophages were evaluated at varying conditions of MNPs concentration and AMF intensity using in vitro cell culture models.Results: The application of MNP/AMF alone at a CEM43 thermal dose below the threshold for skin tissue exhibited a modest efficacy in the eradication of Staphylococcus aureus (S. aureus) biofilm (<1-log reduction). The treatment of antibiotics (ciprofloxacin, vancomycin) alone at a bactericidal concentration for planktonic S. aureus had no significant effect on the eradication of biofilm phase of S. aureus. However, when the biofilm was pre-exposed to mild MNP/AMF hyperthermia, the treatment of antibiotics could exhibit bactericidal effects against S. aureus biofilm, which was associated with increased uptake of antibiotics to the bacterial cells. Importantly, the application of MNP/AMF could promote the bactericidal activity of macrophages against intracellular bacteria via MNP-dependent generation of reactive oxygen species (ROS).Conclusion: Our results validate that the application of mild MNP/AMF hyperthermia within a safe thermal dose threshold is synergistic with conventional antibiotics as well as aids host innate immune response of macrophages for the clearance of intracellular bacteria.

RevDate: 2020-01-21

Chen L, Zou Y, Kronfl AA, et al (2020)

Type VI secretion system of Pseudomonas aeruginosa is associated with biofilm formation but not environmental adaptation.

MicrobiologyOpen [Epub ahead of print].

Pseudomonas aeruginosa encodes three type VI secretion systems (T6SSs), namely H1-, H2-, and H3-T6SS. P. aeruginosa hemolysin-coregulated protein (Hcp) is the effector protein and the hallmark of T6SS. Although T6SS is ubiquitous and affects ecology and human health, its general mechanism and physiological role are still not fully understood. Therefore, in this study, we investigated the impact of the P. aeruginosa T6SS on biofilm formation and environmental adaptation. To this end, we collected P. aeruginosa clinical isolates, divided them into strong biofilm formation (SBF) and nonbiofilm formation (NBF) groups based on their biofilm-forming ability, and compared their associated clinical characteristics. The duration of hospitalization was longer in patients infected with SBF than those infected with NBF strains. The expression levels of T6SS-related genes (hcp1 and hcp3) and a quorum-sensing gene (lasR) were higher in the SBF group as compared to those in the NBF group. In addition, the expression level of lasR was negatively associated with that of hcp1, but was positively associated with those of hcp2 and hcp3. Moreover, we evaluated the expression of T6SS- and biofilm-associated genes in planktonic and biofilm cells of the P. aeruginosa strain PAO1, and constructed strain PAO1△clpV1 to study the adaptation characteristics of H1-T6SS. The expression levels of hcp1, hcp2, hcp3, lasR, and other biofilm-associated genes were significantly higher in PAO1 biofilm cells as compared to those of planktonic cells. However, except for swarming ability as a vital feature for biofilm formation, there were no significant differences in the biofilm-forming ability and expression of biofilm-associated genes, adherence ability, growth characteristics, resistance to acid and osmotic pressure, surface structure, and morphology between the PAO1△clpV1 and PAO1 wild-type strains. Collectively, our results suggest that T6SS might play a role in biofilm formation and that H1-T6SS does not contribute to environmental adaptation in P. aeruginosa.

RevDate: 2020-01-21

Gopalakrishnan V, Masanam E, Ramkumar VS, et al (2020)

Influence of N-acylhomoserine lactonase silver nanoparticles on the quorum sensing system of Helicobacter pyroli: A potential strategy to combat biofilm formation.

Journal of basic microbiology [Epub ahead of print].

The treatment of Helicobacter pylori usually fails due to their ability to form biofilms and resistance to antibiotics. This might potentially lead to gastric carcinoma and mucosa-associated lymphoid tissue lymphoma. In the present study, we elucidate the potential role of N-acylhomoserine lactonase stabilized silver nanoparticles (AiiA-AgNPs) in treating biofilms produced by H. pylori. AiiA-AgNPs inhibited quorum sensing (QS) by degradation of QS molecules, thereby reducing biofilm formation, urease production, and altering cell surface hydrophobicity of H. pylori. AiiA-AgNPs showed no cytotoxic effects on RAW 264.7 macrophages at the effective concentration (1-5 µM) of antibiofilm activity. In addition, AiiA-AgNP in high concentration (80-100 µM) exhibited cytotoxicity against HCT-15 carcinoma cells, depicting its therapeutic role in treating cancer.

RevDate: 2020-01-20

Gellert M, Hardt S, Köder K, et al (2020)

Biofilm-active antibiotic treatment improved the outcome of knee periprosthetic joint infection: Results from a 6-year prospective cohort.

International journal of antimicrobial agents pii:S0924-8579(20)30043-1 [Epub ahead of print].

Biofilm-active antibiotics are suggested to improve the outcome in periprosthetic joint infection (PJI). However, the type, dose and duration of antibiotic treatment is rarely specified and their impact on the outcome is unknown. In this prospective cohort study, we compared the infection and functional outcome in patients with knee PJI treated with and without biofilm-active antibiotics. The infection and functional outcome were evaluated by the Kaplan-Meier survival method to estimate the probability of infection-free survival; comparison between subgroups was performed by log-rank test. The influence of variables on the survival probability was analyzed using univariate and multivariate Cox proportional-hazards regression models. The functional outcome was evaluated by pain intensity and the Knee Injury and Osteoarthritis Outcome Score (KOOS). Of 131 patients, 55 (42%) were treated with and 76 patients (58%) without biofilm-active antibiotics. At follow-up with a median of 3.7 years (range, 2.0-7.6 years), the infection-free survival probability was 74% (95% CI, 61%to 85%) after 1 year and 56% (95% CI, 47% to 66%) after 2 years. The infection-free survival after 1 year was better for patients who received biofilm-active antibiotics than for those who did not (83% vs. 70%, p = 0.040) and remained superior after 2 years (67% vs. 48%, p = 0.038). In addition, biofilm-active antibiotic treatment was associated with lower pain intensity (p = 0.006) and higher KOOS in all five subscales. In patients with knee PJI, biofilm-active antibiotic therapy was associated with better infection outcome, lower pain intensity and better joint function.

RevDate: 2020-01-20

Simkins JW, Stewart PS, Codd SL, et al (2020)

Microbial growth rates and local external mass transfer coefficients in a porous bed biofilm system measured by 19 F magnetic resonance imaging of structure, oxygen concentration, and flow velocity.

Biotechnology and bioengineering [Epub ahead of print].

19 F nuclear magnetic resonance (NMR) oximetry and 1 H NMR velocimetry were used to non-invasively map oxygen concentrations and hydrodynamics in space and time in a model packed bed biofilm system in the presence and absence of flow. The development of a local oxygen sink associated with a single gel bead inoculated with respiring Escherichia coli was analyzed with a phenomenological model to determine the specific growth rate of the bacteria in situ, returning a value (0.66 h-1) that was close to that measured independently in planktonic culture (0.62 h-1). The decay of oxygen concentration in and around the microbiologically active bead was delayed and slower in experiments conducted under continuous flow in comparison to no-flow experiments. Concentration boundary layer thicknesses were determined and Sherwood numbers calculated to quantify external mass transfer resistance. Boundary layers were thicker in no-flow experiments compared to experiments with flow. Whereas the oxygen concentration profile across a reactive biofilm particle was symmetric in no-flow experiments, it was asymmetric with respect to flow direction in flow experiments with Sherwood numbers on the leading edge (Sh = 7) being larger than the trailing edge (Sh = 3.5). The magnitude of the experimental Sh was comparable to values predicted by a variety of correlations. These spatially resolved measurements of oxygen distribution in a geometrically complex model reveal in innovative detail the local coupling between microbial growth, oxygen consumption, and external mass transfer. This article is protected by copyright. All rights reserved.

RevDate: 2020-01-20

Kassinger SJ, ML van Hoek (2020)

Biofilm architecture: An emerging synthetic biology target.

Synthetic and systems biotechnology, 5(1):1-10 pii:S2405-805X(20)30001-6.

Synthetic biologists are exploiting biofilms as an effective mechanism for producing various outputs. Metabolic optimization has become commonplace as a method of maximizing system output. In addition to production pathways, the biofilm itself contributes to the efficacy of production. The purpose of this review is to highlight opportunities that might be leveraged to further enhance production in preexisting biofilm production systems. These opportunities may be used with previously established production systems as a method of improving system efficiency further. This may be accomplished through the reduction in the cost of establishing and maintaining biofilms, and maintenance of the enhancement of product yield per unit of time, per unit of area, or per unit of required input.

RevDate: 2020-01-20

Minami M, Takase H, Nakamura M, et al (2019)

Methanol extract of Lonicera caerulea var. emphyllocalyx fruit has anti-motility and anti-biofilm activity against enteropathogenic Escherichia coli.

Drug discoveries & therapeutics, 13(6):335-342.

Foodborne diseases have become a worldwide problem that threatens public health and welfare. Enteropathogenic Escherichia coli (EPEC) is one of major pathogens of moderate to severe diarrhea. The increased prevalence of EPEC strains that produce extended spectrum β-lactamase (ESBL) has deepened the problem. The fruit of Lonicera caerulea var. emphyllocalyx (LCE) has been used as a traditional food preservative and medicine in northern temperate zones such as Hokkaido Island, Japan. In this study, we investigated the antibacterial effect of LCE fruit extract (LCEE) against EPEC. The antibacterial activities of LCEE were examined by bacterial growth, time-kill curve, soft-agar motility, electron microscopy, and 96 well-microplate biofilm assays. We also investigated the bacterial mRNA expression of biofilm-associated genes (fliC, csgA, and fimA) by quantitative real-time PCR assays. LCEE was found to suppress the growth, time-kill curve, and spread of EPEC. It also reduced the biofilm formation in a dose-dependent manner. Morphological analysis using transmission and scanning electron microscopy revealed that LCEE diminished the function of flagella resulting in reduced motility and biofilm formation. The mRNA expression of all three biofilm associated genes was downregulated under LCEE treatment. Extracts of the fruit of LCE inhibit the motility and biofilm formation of EPEC as a result of the inhibition of flagella development and function. We propose LCEE as a therapeutic candidate for the effective therapy of EPEC-associated infectious diseases.

RevDate: 2020-01-20

Badaró MM, Bueno FL, Arnez RM, et al (2020)

The effects of three disinfection protocols on Candida spp., denture stomatitis, and biofilm: A parallel group randomized controlled trial.

The Journal of prosthetic dentistry pii:S0022-3913(19)30616-X [Epub ahead of print].

STATEMENT OF PROBLEM: Antifungals are used to treat Candida infections. However, because of increased antifungal resistance and the length of antifungal therapy, Candida spp. infections can be prevented using the prosthesis hygiene method. Therefore, establishing efficient, safe, and low-cost hygiene protocols for complete denture wearers is necessary.

PURPOSE: The purpose of this clinical trial was to compare 10% Ricinus communis (RC10%) and 0.5% chloramine-T (CT0.5%) with negative (water) and positive (0.25% sodium hypochlorite [SH0.25%]) controls to establish a protocol to treat denture stomatitis (DS), remove denture biofilm, reduce overall microbiota, and decrease Candida spp. on the palate and denture bases.

MATERIAL AND METHODS: This randomized, double blind, controlled clinical trial allocated 60 DS-positive participants in parallel groups: RC10%, CT0.5%, negative control, and SH0.25%. All participants brushed their palate and dentures and applied 1 of the solutions only to the denture. The following outcomes were assessed at baseline and after 7 and 37 days: Candida spp. counts, frequency of species by presumptive identification, DS severity, and photographic quantification of biofilm. The Kruskal-Wallis and Friedman tests with stepwise step-down post hoc test compared the anticandidal effect and the DS score (between groups and time). ANOVA and the Tukey post hoc test were used for biofilm removal comparison (α=.05).

RESULTS: Microbial counts were solution- and time-dependent for dentures, with C. albicans, C. tropicalis, and C. glabrata being the most prevalent species. RC10% presented similar results to baseline and control after 7 and 37 days. CT0.5% reduced the CFU/mL compared with the baseline. SH0.25% was the most effective. DS reduced in all groups, independent of the solution. SH0.25% reduced biofilm the most, followed by RC10%. CT0.5% was similar to the control.

CONCLUSIONS: SH0.25% demonstrated potential for Candida spp. control in denture wearers with DS. The other protocols showed intermediate activity and might be more suitable for longer immersion periods.

RevDate: 2020-01-19

Ryu EJ, An SJ, Sim J, et al (2020)

Use of d-galactose to regulate biofilm growth of oral streptococci.

Archives of oral biology, 111:104666 pii:S0003-9969(19)30883-0 [Epub ahead of print].

In the oral microbial community, commensals can compete with pathogens and reduce their colonization in the oral cavity. A substance that can inhibit harmful bacteria and enrich beneficial bacteria is required to maintain oral health. The purpose of this study was to examine the effect of d-galactose on the biofilm formation of the cariogenic bacteria Streptococcus mutans and oral commensal streptococci and to evaluate their use in solution and in paste form. Biofilms of S. mutans, Streptococcus oralis, and Streptococcus mitis were formed on saliva-coated glass slips in the absence or presence of d-galactose and evaluated by staining with 1 % crystal violet. d-Galactose significantly inhibited the biofilm formation of S. mutans at concentrations ranging from 2 μM to 200 mM but increased the biofilm formation of S. oralis and S. mitis at concentrations of 2-200 mM. d-Galactose significantly inhibited three glucosyltransferase genes, gtfB, gtfC, and gtfD. The effect of d-galactose in the form of solution and paste was evaluated using bovine teeth. Pretreatment with 100 mM d-galactose on bovine teeth resulted in significantly reduced S. mutans biofilm formation. Our results suggest that d-galactose can be a candidate substance for the development of oral hygiene products to prevent caries by inhibiting the biofilm formation of S. mutans and simultaneously increasing the biofilm formation of commensal oral streptococci.

RevDate: 2020-01-19

Keleştemur S, Çobandede Z, M Çulha (2020)

Biofilm formation of clinically important microorganisms on 2D and 3D poly (methyl methacrylate) substrates: A surface-enhanced Raman scattering study.

Colloids and surfaces. B, Biointerfaces, 188:110765 pii:S0927-7765(19)30909-9 [Epub ahead of print].

Clinically relevant microorganisms threaten patient's health often through biofilm formation on polymeric medical devices and implants. Poly (methyl methacrylate) is a commonly used polymer in medical implants and dental devices. In this study, biofilm characteristics of model microorganisms, Pseudomonas aeruginosa, Staphylococcus epidermidis and Candida albicans, were investigated at molecular level on 2-dimensional (2D) and 3-dimensional (3D) PMMA substrates to understand the influence of surface structures on biofilm formation and also to demonstrate the discrimination of microorganisms according to their metabolic activities by utilizing surface-enhanced Raman scattering (SERS). It was found that the fibrous 3D structure enhanced the assembly of microorganisms and enriched the biofilm structure while smooth polymeric surface decreased the biofilm formation rate and variety of biofilm content. Among the studied microorganisms, Pseudomonas aeruginosa and Candida albicans had a higher tendency to form biofilm on both 2D and 3D PMMA substrates. Although Staphlylococcus epidermidis showed slow adaption on PMMA surfaces, the 3D porous surfaces increased its biofilm formation rate significantly compared to 2D surface.

RevDate: 2020-01-20

Abriat C, Enriquez K, Virgilio N, et al (2020)

Mechanical and microstructural insights of Vibrio cholerae and Escherichia coli dual-species biofilm at the air-liquid interface.

Colloids and surfaces. B, Biointerfaces, 188:110786 pii:S0927-7765(20)30016-3 [Epub ahead of print].

Biofilm is the dominant microbial form found in nature, in which bacterial species are embedded in a self-produced extracellular matrix (ECM). These complex microbial communities are responsible for several infections when they involve multispecies pathogenic bacteria. In previous studies, interfacial rheology proved to be a unique quantitative technique to follow in real-time the biofilm formation at the air-liquid interface. In this work, we studied a model system composed of two bacteria pathogenic capable of forming a pellicle biofilm, V. cholerae and E. coli. We used an integrated approach by combining a real-time quantitative analysis of the biofilm rheological properties, with the investigation of major matrix components and the pellicle microstructure. The results highlight the competition for the interface between the two species, driven by the biofilm formation growth rate. In the dual-species biofilm, the viscoelastic properties were dominated by V. cholera, which formed a mature biofilm 18 h faster than E. coli. The microstructure of the dual-species biofilm revealed a similar morphology to V. cholerae alone when both bacteria were initially added at the same amount. The analysis of some major ECM components showed that E. coli was not able to produce curli in the presence of V. cholerae, unless enough time was given for E. coli to colonize the air-liquid interface first. E. coli secreted phosphoethanolamine (pEtN) cellulose in the dual-species biofilm, but did not form a filamentous structure. Our pathogenic model system demonstrated the importance of the biofilm growth rate for multispecies biofilm composition at the air-liquid interface.

RevDate: 2020-01-18

Ahmed K, Ahmed H, Ahmed FA, et al (2020)

Analysis of anti-microbial and anti-biofilm activity of hand washes and sanitizers against S. aureus and P. aeruginosa.

JPMA. The Journal of the Pakistan Medical Association, 70(1):100-104.

OBJECTIVE: To analyse the biofilm-forming potential of clinical isolates of Staphylococcus aureus and Pseudomonas aeruginosa, and to assess antimicrobial activity of commonly used sanitizers in hospital and laboratory settings.

METHODS: The study was conducted at Aga Khan University Karachi from August 2016 to January 2017. The biofilm-forming potential of Staphylococcus aureus and Pseudomonas aeruginosa clinical isolates were evaluated qualitatively using air-liquid interface tube method, and air-liquid interface cover slip assay. The antimicrobial activity of commonly-used hand-washes and sanitizers were assessed using agar well diffusion method, while the anti-biofilm activity of the hand-washes and sanitizers was qualitatively assessed using air-liquid interface covers lip as s ay.

RESULTS: Of the eight hand-washes and sanitizers, 2(25%) showed antimicrobial activity against both Staphylococcus aureus and Pseudomonas aeruginosa, while 2(25%) exhibited antimicrobial activity against either S. aureus or P. aeruginosa. Also, 4 (50%) of them showed no inhibitory activity against S. aureus and P. aeruginosa.

CONCLUSIONS: The findings shall have important consequences with regards to infection control in hospital and laboratory settings.

RevDate: 2020-01-20

Sun J, Yang P, Huang S, et al (2020)

Enhanced removal of veterinary antibiotic from wastewater by photoelectroactive biofilm of purple anoxygenic phototroph through photosynthetic electron uptake.

The Science of the total environment, 713:136605 pii:S0048-9697(20)30115-7 [Epub ahead of print].

Purple anoxygenic phototrophs have been recently attracted substantial attention for their growing potential in wastewater treatment and their diverse metabolic patterns can be regulated for process control and optimization. In this study, the photoheterotrophic metabolism of Rhodopseudomonas palustris (R. palustris) was modified by photosynthetic electron uptake using a poised electrode which was explored to enhance removal of veterinary antibiotic from aqueous medium. The results showed that R. palustris grown as biofilm on electrode surface had excellent photoelectroactive activity and the photosynthetic electron uptake from the photoelectroactive biofilm significantly enhanced antibiotic florfenicol (FLO) degradation. The specific degradation rate of FLO at the set electrode potential of 0 V was 2.59-fold higher than that without applied potential. Enhanced co-metabolic reductive dehalogenation by use of the photosynthetic electrons extracted from co-substrate was mainly responsible for FLO degradation which eliminated the antibacterial activity of FLO. The electrode potential controlled the processes of photosynthetic electron uptake and its resultant FLO degradation. The fastest degradation of FLO was achieved at 0 V because the electrode poised at this potential stroke a proper balance between the enhancing photosynthetic electron uptake by serving as electron acceptor and minimizing competition with FLO for the photosynthetic electron from co-substrate. The activity of photoelectroactive biofilm was not negatively affected by FLO at environmental relevant concentration, suggesting its great potential for removal of antibiotic contaminants in wastewater. R. palustris could serve as a reservoir for floR resistance gene but its abundance can be diminished by choosing appropriate electrode potential.

RevDate: 2020-01-17

Stüken A, THA Haverkamp (2020)

Metagenomic Sequences of Three Drinking Water and Two Shower Hose Biofilm Samples Treated with or without Copper-Silver Ionization.

Microbiology resource announcements, 9(3): pii:9/3/e01220-19.

We announce five shotgun metagenomics data sets from two Norwegian premise plumbing systems. The samples were shotgun sequenced on two lanes of an Illumina HiSeq 3000 instrument (THRUplex chemistry, 151 bp, paired-end reads), providing an extensive resource for sequence analyses of tap water and biofilm microbial communities.

RevDate: 2020-01-17

Speranza B, Corbo MR, Campaniello D, et al (2020)

Biofilm formation by potentially probiotic Saccharomyces cerevisiae strains.

Food microbiology, 87:103393.

Four wild strains of Saccharomyces cerevisiae and the collection strain S. cerevisiae var. boulardii ATCC MYA-796 were used as test organisms to study the effect of some environmental conditions on the formation of biofilm by potentially probiotic yeasts. In a first step, the formation of biofilm was studied in four different media (YPD-Yeast Peptone Glucose; diluted YPD; 2% BP, a medium containing only bacteriological peptone; 2% GLC, a medium containing only glucose). Then, the dilution of YPD was combined with pH and temperature through a mixture design to assess the weight of the interaction of the variables; the experiments were done on S. boulardii and on S. cerevisiae strain 4. The dilution of nutrients generally determined an increased biofilm formation, whereas the effect of pH relied upon the strain. For S. cerevisiae strain 4, the highest level of sessile cells was found at pH 4-5, while S. boulardii experienced an enhanced biofilm formation at pH 6.0. Concerning temperature, the highest biofilm formation was found at 25-30 °C for both strains. The importance of this work lies in its extension of our knowledge of the effect of different environmental conditions on biofilm formation by potentially probiotic S. cerevisiae strains, as a better understanding of this trait could be an important screening tool into the selection of new multifunctional yeasts.

RevDate: 2020-01-17

Vazquez-Armenta FJ, Hernandez-Oñate MA, Martinez-Tellez MA, et al (2020)

Quercetin repressed the stress response factor (sigB) and virulence genes (prfA, actA, inlA, and inlC), lower the adhesion, and biofilm development of L. monocytogenes.

Food microbiology, 87:103377.

The present study explored the effect of quercetin on the expression of virulence genes actA, inlA, inlC, and their regulatory components, sigB and prfA, in L. monocytogenes. Furthermore, the physicochemical changes on the surface, membrane permeability, and biofilm formation of quercetin-treated bacteria were evaluated. An inhibitory dose-dependent effect of quercetin (0.1-0.8 mM) was observed on the cell attachment on stainless steel at 2 and 6 h at 37 °C. Quercetin at 0.8 mM prevented the biofilm formation on stainless steel surfaces after 6 h of incubation at 37 °C, while the untreated bacteria formed biofilms with a cell density of 5.1 Log CFU/cm2. The microscopic analysis evidenced that quercetin at 0.2 mM decreased the biovolume and covered area of the attached micro-colonies. Also, sigB, prfA, inlA, inlC, and actA genes were downregulated by 7-29 times lower compared to untreated bacteria. In addition, quercetin decreased the superficial cell charge, increased the membrane permeability, and its surface hydrophobicity. These results demonstrated that quercetin prevented biofilm formation, repressed the genes of stress and virulence of L. monocytogenes and also altered the physicochemical cell properties.

RevDate: 2020-01-18

Chen H, Zhang B, Weir MD, et al (2020)

S. mutans gene-modification and antibacterial resin composite as dual strategy to suppress biofilm acid production and inhibit caries.

Journal of dentistry pii:S0300-5712(20)30012-9 [Epub ahead of print].

OBJECTIVE: Composite restorations are increasingly popular, but recurrent caries is a main reason for composite restoration failures. The objectives of this study were to investigate a dual strategy of combining rnc gene-deletion for Streptococcus mutans (S. mutans) with antibacterial dimethylaminohexadecyl methacrylate (DMAHDM) composite, and determine the effects of rnc gene-deletion alone, DMAHDM composite alone, and rnc-deletion plus DMAHDM composite, on biofilm growth and lactic acid production.

METHODS: Parent S. mutans (UA159, ATCC 700610) and rnc-deleted S. mutans were used. DMAHDM was incorporated into a composite at mass fractions of 0%, 1.5%, and 3%. Gene expressions for biofilm formation and drug resistance were analyzed using quantitative real-time polymerase chain reaction (qRT-PCR). Biofilms were grown on composite surfaces for 2 days. Live/dead, biomass, polysaccharide, metabolic activity (MTT), colony-forming units (CFU) and lactic acid production of biofilms were evaluated.

RESULTS: Compared to the parent S. mutans, the rnc-deletion technique yielded significantly less biofilm biomass, polysaccharides, metabolic activity, CFU, and lactic acid for biofilms grown on control composite (p < 0.05). With no gene modification, the biofilm CFU was decreased by 5-6 logs at 3% DMAHDM, when compared to control composite group. The dual strategy of combining rnc-deletion with 3% DMAHDM composite achieved the strongest biofilm-inhibition, with the greatest reduction in CFU by 8 logs. The combination of rnc-deletion with 3% DMAHDM composite decreased the biofilm lactic acid production by 95% (p < 0.05).

CONCLUSIONS: The dual strategy of rnc-deletion plus DMAHDM composite produced synergistic effects and achieved the strongest biofilm-inhibition. This method has great potential to inhibit dental caries and is promising to reduce secondary caries and protect tooth structures.

RevDate: 2020-01-16

Lara HH, Ixtepan-Turrent L, Jose Yacaman M, et al (2020)

Inhibition of Candida auris Biofilm Formation on Medical and Environmental Surfaces by Silver Nanoparticles.

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

Candida auris is an emerging pathogenic fungus implicated in healthcare-associated outbreaks and causes bloodstream infections associated with high mortality rates. Biofilm formation represents one of the major pathogenetic traits associated with this microorganism. Unlike most other Candida species, C. auris has the ability to survive for weeks on different surfaces. Therefore, there is an urgent need to develop new effective control strategies to combat the threat of C. auris. Advances in nanotechnologies have emerged that carry significant potential impact against Candida biofilms. We obtained pure round silver nanoparticles (AgNPs) (1 to 3 nm in diameter) using a microwave-assisted synthetic approach. When tested against C. auris, our results indicated a potent inhibitory activity both on biofilm formation (half maximal inhibitory concentration (IC50) of 0.06 ppm) and against preformed biofilms (IC50 of 0.48 ppm). Scanning electron microscopy images of AgNP-treated biofilms showed cell wall damage mostly by disruption and distortion of the outer surface of the fungal cell wall. In subsequent experiments AgNPs were used to functionalize medical and environmental surfaces. Silicone elastomers functionalized with AgNPs demonstrated biofilm inhibition (>50%) at relatively low concentrations (2.3 to 0.28 ppm). Bandage dressings loaded with AgNPs inhibited growth of C. auris biofilms by more than 80% (2.3 to 0.017 ppm). Also, to demonstrate long-lasting protection, dressings loaded with AgNPs (0.036 ppm) were washed thoroughly with phosphate-buffered saline, maintaining protection against the C. auris growth from cycles 1 to 3 (>80% inhibition) and from cycles 4 to 6 (>50% inhibition). Our results demonstrate the dose-dependent activity of AgNPs against biofilms formed by C. auris on both medical (silicone elastomer) and environmental (bandage fibers) surfaces. The AgNPs-functionalized fibers retain the fungicidal effect even after repeated thorough washes. Overall these results point to the utility of silver nanoparticles to prevent and control infections caused by this emerging pathogenic fungus.

RevDate: 2020-01-16

Guan W, Wang T, Huang Q, et al (2020)

A LuxR-type regulator, AcrR, regulates flagellar assembly and contributes to virulence, motility, biofilm formation, and growth ability of Acidovorax citrulli.

Molecular plant pathology [Epub ahead of print].

LuxR-type regulators regulate many bacterial processes and play important roles in bacterial motility and virulence. Acidovorax citrulli is a seedborne bacterial pathogen responsible for bacterial fruit blotch, which causes great losses in melon and watermelon worldwide. We identified a LuxR-type, nonquorum sensing-related regulator, AcrR, in the group II strain Aac-5 of A. citrulli. We found that the acrR mutant lost twitching and swimming motilities, and flagellar formation. It also showed reduced virulence, but increased biofilm formation and growth ability. Transcriptomic analysis revealed that 394 genes were differentially expressed in the acrR mutant of A. citrulli, including 33 genes involved in flagellar assembly. Our results suggest that AcrR may act as a global regulator affecting multiple important biological functions of A. citrulli.

RevDate: 2020-01-16

Vitális E, Nagy F, Tóth Z, et al (2020)

Candida biofilm production is associated with higher mortality in patients with candidaemia.

Mycoses [Epub ahead of print].

BACKGROUND: Candidaemia is a common life-threatening disease among hospitalised patients, but the effect of the Candida biofilm-forming ability on the clinical outcome remains controversial.

OBJECTIVE: The aim was to determine the impact of biofilms, specifically focusing on biofilm mass and metabolic activity, on the mortality in candidaemia.

PATIENTS/METHODS: The clinical data of patients (n=127) treated at the University of Debrecen, Clinical Centre, between January 2013 and December 2018, were investigated retrospectively. Biofilm formation was assessed using the crystal violet and XTT assays, measuring the biofilm mass and metabolic activity, respectively. Isolates were classified as low, intermediate and high biofilm producers both regarding biofilm mass and metabolic activity. The susceptibility of one-day-old biofilms to fluconazole, amphotericin B, anidulafungin, caspofungin and micafungin was evaluated and compared to planktonic susceptibility.

RESULTS: Intermediate/high biofilm mass was associated with significantly higher mortality (61%). All Candida tropicalis, Candida parapsilosis and Candida glabrata isolates originating from fatal infections were intermediate/high biofilm producers, whereas this ratio was 85% for Candida albicans. Solid malignancy was associated with intermediate/high biofilm producers (p=0.043). The mortality was significantly higher in infections caused by Candida strains producing biofilms with intermediate/high metabolic activity (62% vs. 33%, p=0.010). The ratio of concomitant bacteraemia was higher for isolates forming biofilms with low metabolic activity (53% vs. 28%, p=0.015).

CONCLUSIONS: This study provides evidence that the Candida biofilms especially with intermediate/high metabolic activity are related to higher mortality in candidemia.

RevDate: 2020-01-16

Zinicovscaia I, Safonov A, Boldyrev K, et al (2020)

Selective metal removal from chromium-containing synthetic effluents using Shewanella xiamenensis biofilm supported on zeolite.

Environmental science and pollution research international pii:10.1007/s11356-020-07690-y [Epub ahead of print].

A scheme of selective removal of metal ions from chromium-containing synthetic solutions with the following chemical composition, Cr (VI)-Fe (III), Cr (VI)-Fe (III)-Ni (II), Cr (VI)-Fe (III)-Ni (II)-Zn (II), and Cr (VI)-Fe (III)-Ni (II)-Zn (II)-Cu (II)) by Shewanella xiamenensis biofilm immobilized on a zeolite support, was proposed. Three biological processes, biosorption, bioaccumulation, and longtime bioreduction, were applied for metal removal. The process of Zn (II), Ni (II), and Cu (II) showed to be pH dependent. The maximum removal of Ni (II) was achieved during a 1-hour biosorption process at pH 5.0-6.0, of Zn (II) at pH 5.0, and of Cu (II) at pH 3.0. Chromium (VI) and Fe (III) ions were more efficiently removed by bioaccumulation. Chromium (VI) removal in the studied systems varied from 16.4% to 34.8 and of iron from 55.8 to 94.6%. In a long-term bioreduction experiment, it was possible to achieve complete reduction of Cr (VI) to Cr (III) ions by Shewanella xiamenensis in 42 days and by Shewanella xiamenensis biofilm on zeolite in 35 days. Shewanella oneidensis can be effectively used to remove metal ions from chemically complex effluents.

RevDate: 2020-01-16

Drotleff B, Roth SR, Henkel K, et al (2020)

Lipidomic profiling of non-mineralized dental plaque and biofilm by untargeted UHPLC-QTOF-MS/MS and SWATH acquisition.

Analytical and bioanalytical chemistry pii:10.1007/s00216-019-02364-2 [Epub ahead of print].

Dental plaque is a structurally organized biofilm which consists of diverse microbial colonies and extracellular matrix. Its composition may change when pathogenic microorganisms become dominating. Therefore, dental biofilm or plaque has been frequently investigated in the context of oral health and disease. Furthermore, its potential as an alternative matrix for analytical purposes has also been recognized in other disciplines like archeology, food sciences, and forensics. Thus, a careful in-depth characterization of dental plaque is worthwhile. Most of the conducted studies focused on the screening of microbial populations in dental plaque. Their lipid membranes, on the other hand, may significantly impact substance (metabolite) exchange within microbial colonies as well as xenobiotics uptake and incorporation into teeth. Under this umbrella, a comprehensive lipidomic profiling for determination of lipid compositions of in vivo dental plaque samples and of in vitro cultivated biofilm as surrogate matrix to be used for analytical purposes has been performed in this work. An untargeted lipidomics workflow utilizing a ultra-high-performance liquid chromatography (UHPLC)-quadrupole-time-of-flight (QTOF) platform together with comprehensive SWATH (sequential window acquisition of all theoretical fragment ion mass spectra) acquisition and compatible software (MS-DIAL) that comprises a vast lipid library has been adopted to establish an extensive lipidomic fingerprint of dental plaque. The main lipid components in dental plaque were identified as triacylglycerols, followed by cholesterol, cholesteryl esters as well as diacylglycerols, and various phospholipid classes. In vivo plaque is a rare matrix which is usually available in very low amounts. When higher quantities for specific research assays are required, efficient ways to produce an appropriate surrogate matrix are mandatory. A potential surrogate matrix substituting dental plaque was prepared by cultivation of in vitro biofilm from saliva and similarities and differences in the lipidomics profile to in vivo plaque were mapped by statistical evaluation post-analysis. It was discovered that most lipid classes were highly elevated in the in vitro biofilm samples, in particular diacylglycerols, phosphatidylglycerols, and phosphatidylethanolamines (PEs). Furthermore, an overall shift from even-chain lipid species to odd-chain lipids was observed in the cultivated biofilms. On the other hand, even-chain phosphatidylcholines (PCs), lysoPCs, cholesteryl esters, and cholesterol-sulfate were shown to be specifically increased in plaque samples. Graphical abstract.

RevDate: 2020-01-19

Cui Y, Schmid BV, Cao H, et al (2020)

Evolutionary selection of biofilm-mediated extended phenotypes in Yersinia pestis in response to a fluctuating environment.

Nature communications, 11(1):281.

Yersinia pestis is transmitted from fleas to rodents when the bacterium develops an extensive biofilm in the foregut of a flea, starving it into a feeding frenzy, or, alternatively, during a brief period directly after feeding on a bacteremic host. These two transmission modes are in a trade-off regulated by the amount of biofilm produced by the bacterium. Here by investigating 446 global isolated Y. pestis genomes, including 78 newly sequenced isolates sampled over 40 years from a plague focus in China, we provide evidence for strong selection pressures on the RNA polymerase ω-subunit encoding gene rpoZ. We demonstrate that rpoZ variants have an increased rate of biofilm production in vitro, and that they evolve in the ecosystem during colder and drier periods. Our results support the notion that the bacterium is constantly adapting-through extended phenotype changes in the fleas-in response to climate-driven changes in the niche.

RevDate: 2020-01-16

Park C, Jung HS, Park S, et al (2020)

Dominance of Gas-Eating, Biofilm-Forming Methylobacterium Species in the Evaporator Cores of Automobile Air-Conditioning Systems.

mSphere, 5(1): pii:5/1/e00761-19.

Microbial communities in the evaporator core (EC) of automobile air-conditioning systems have a large impact on indoor air quality, such as malodor and allergenicity. DNA-based microbial population analysis of the ECs collected from South Korea, China, the United States, India, and the United Arab Emirates revealed the extraordinary dominance of Methylobacterium species in EC biofilms. Mixed-volatile organic compound (VOC) utilization and biofilm-forming capabilities were evaluated to explain the dominance of Methylobacterium species in the ECs. The superior growth of all Methylobacterium species could be possible under mixed-VOC conditions. Interestingly, two lifestyle groups of Methylobacterium species could be categorized as the aggregator group, which sticks together but forms a small amount of biofilm, and the biofilm-forming group, which forms a large amount of biofilm, and their genomes along with phenotypic assays were analyzed. Pili are some of the major contributors to the aggregator lifestyle, and succinoglycan exopolysaccharide production may be responsible for the biofilm formation. However, the coexistence of these two lifestyle Methylobacterium groups enhanced their biofilm formation compared to that with each single culture.IMPORTANCE Air-conditioning systems (ACS) are indispensable for human daily life; however, microbial community analysis in automobile ACS has yet to be comprehensively investigated. A bacterial community analysis of 24 heat exchanger fins from five countries (South Korea, China, the United States, India, and the United Arab Emirates [UAE]) revealed that Methylobacterium species are some of the dominant bacteria in automobile ACS. Furthermore, we suggested that the predominance of Methylobacterium species in automobile ACS is due to the utilization of mixed volatile organic compounds and their great ability for aggregation and biofilm formation.

RevDate: 2020-01-16

Lee MJ, Kim MJ, Oh SH, et al (2020)

Novel Dental Poly (Methyl Methacrylate) Containing Phytoncide for Antifungal Effect and Inhibition of Oral Multispecies Biofilm.

Materials (Basel, Switzerland), 13(2): pii:ma13020371.

Despite the many advantages of poly (methyl methacrylate) (PMMA) as a dental polymer, its antifungal and antibacterial effects remain limited. Here, phytoncide was incorporated into PMMA to inhibit fungal and biofilm accumulation without impairing the basic and biological properties of PMMA. A variable amount of phytoncide (0 wt % to 5 wt %) was incorporated into PMMA, and the basic material properties of microhardness, flexural strength and gloss were evaluated. In addition, cell viability was confirmed by MTT assay. This MTT assay measures cell viability via metabolic activity, and the color intensity of the formazan correlates viable cells. The fungal adhesion and viability on the PMMA surfaces were evaluated using Candida albicans (a pathogenic yeast). Finally, the thickness of saliva-derived biofilm was estimated. The flexural strength of PMMA decreased with increasing phytoncide contents, whereas there were no significant differences in the microhardness and gloss (p > 0.05) and the cell viability (p > 0.05) between the control and the phytoncide-incorporated PMMA samples. The amounts of adherent Candida albicans colony-forming unit (CFU) counts, and saliva-derived biofilm thickness were significantly lower in the phytoncide-incorporated PMMA compared to the control (p < 0.05). Hence, it was concluded that the incorporation of appropriate amounts of phytoncide in PMMA demonstrated antifungal effects while maintaining the properties, which could be a possible use in dentistry application such as denture base resin.

RevDate: 2020-01-16

Qian W, Wang W, Zhang J, et al (2020)

Sanguinarine Inhibits Mono- and Dual-Species Biofilm Formation by Candida albicans and Staphylococcus aureus and Induces Mature Hypha Transition of C. albicans.

Pharmaceuticals (Basel, Switzerland), 13(1): pii:ph13010013.

Previous studies have reported that sanguinarine possesses inhibitory activities against several microorganisms, but its effects on mono- and dual-species biofilms of C. albicans and S. aureus have not been fully elucidated. In this study, we aimed to evaluate the efficacy of sanguinarine for mono- and dual-species biofilms and explore its ability to induce the hypha-to-yeast transition of C. albicans. The results showed that the minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC90) of sanguinarine against C. albicans and S. aureus mono-species biofilms was 4, and 2 μg/mL, respectively, while the MIC and MBIC90 of sanguinarine against dual-species biofilms was 8, and 4 μg/mL, respectively. The decrease in the levels of matrix component and tolerance to antibiotics of sanguinarine-treated mono- and dual-species biofilms was revealed by confocal laser scanning microscopy combined with fluorescent dyes, and the gatifloxacin diffusion assay, respectively. Meanwhile, sanguinarine at 128 and 256 μg/mL could efficiently eradicate the preformed 24-h biofilms by mono- and dual-species, respectively. Moreover, sanguinarine at 8 μg/mL could result in the transition of C. albicans from the mature hypha form to the unicellular yeast form. Hence, this study provides useful information for the development of new agents to combat mono- and dual-species biofilm-associated infections, caused by C. albicans and S. aureus.

RevDate: 2020-01-16

Savijoki K, Miettinen I, Nyman TA, et al (2020)

Growth Mode and Physiological State of Cells Prior to Biofilm Formation Affect Immune Evasion and Persistence of Staphylococcus aureus.

Microorganisms, 8(1): pii:microorganisms8010106.

The present study investigated Staphylococcus aureus ATCC25923 surfaceomes (cell surface proteins) during prolonged growth by subjecting planktonic and biofilm cultures (initiated from exponential or stationary cells) to label-free quantitative surfaceomics and phenotypic confirmations. The abundance of adhesion, autolytic, hemolytic, and lipolytic proteins decreased over time in both growth modes, while an opposite trend was detected for many tricarboxylic acid (TCA) cycle, reactive oxygen species (ROS) scavenging, Fe-S repair, and peptidolytic moonlighters. In planktonic cells, these changes were accompanied by decreasing and increasing adherence to hydrophobic surface and fibronectin, respectively. Specific RNA/DNA binding (cold-shock protein CspD and ribosomal proteins) and the immune evasion (SpA, ClfA, and IsaB) proteins were notably more abundant on fully mature biofilms initiated with stationary-phase cells (SDBF) compared to biofilms derived from exponential cells (EDBF) or equivalent planktonic cells. The fully matured SDBF cells demonstrated higher viability in THP-1 monocyte/macrophage cells compared to the EDBF cells. Peptidoglycan strengthening, specific urea-cycle, and detoxification enzymes were more abundant on planktonic than biofilm cells, indicating the activation of growth-mode specific pathways during prolonged cultivation. Thus, we show that S. aureus shapes its surfaceome in a growth mode-dependent manner to reach high levofloxacin tolerance (>200-times the minimum biofilm inhibitory concentration). This study also demonstrates that the phenotypic state of the cells prior to biofilm formation affects the immune-evasion and persistence-related traits of S. aureus.

RevDate: 2020-01-15

DelMain EA, Moormeier DE, Endres JL, et al (2020)

Stochastic Expression of Sae-Dependent Virulence Genes during Staphylococcus aureus Biofilm Development Is Dependent on SaeS.

mBio, 11(1): pii:mBio.03081-19.

The intricate process of biofilm formation in the human pathogen Staphylococcus aureus involves distinct stages during which a complex mixture of matrix molecules is produced and modified throughout the developmental cycle. Early in biofilm development, a subpopulation of cells detaches from its substrate in an event termed "exodus" that is mediated by SaePQRS-dependent stochastic expression of a secreted staphylococcal nuclease, which degrades extracellular DNA within the matrix, causing the release of cells and subsequently allowing for the formation of metabolically heterogenous microcolonies. Since the SaePQRS regulatory system is involved in the transcriptional control of multiple S. aureus virulence factors, the expression of several additional virulence genes was examined within a developing biofilm by introducing fluorescent gene reporter plasmids into wild-type S. aureus and isogenic regulatory mutants and growing these strains in a microfluidic system that supplies the bacteria with a constant flow of media while simultaneously imaging developing biofilms in 5-min intervals. This study demonstrated that multiple virulence genes, including nuc, were expressed stochastically within a specialized subpopulation of cells in nascent biofilms. We demonstrated that virulence genes regulated by SaePQRS were stochastically expressed in nearly all strains examined whereas Agr-regulated genes were expressed more homogenously within maturing microcolonies. The commonly used Newman strain contains a variant of SaeS (SaeSP) that confers constitutive kinase activity to the protein and caused this strain to lack the stochastic expression pattern observed in other strain backgrounds. Importantly, repair of the SaeSP allele resulting in reversion to the well-conserved SaeS L allele found in other strains restored stochastic expression in this strain.IMPORTANCEStaphylococcus aureus is an important human pathogen capable of colonizing diverse tissue types and inducing severe disease in both immunocompromised and otherwise healthy individuals. Biofilm infections caused by this bacterial species are of particular concern because of their persistence, even in the face of intensive therapeutic intervention. The results of the current study demonstrate the stochastic nature of Sae-mediated virulence gene expression in S. aureus and indicate that this regulatory system may function as a "bistable switch" in a manner similar to that seen with regulators controlling competence gene expression in Bacillus subtilis and persister cell formation in Escherichia coli The results of this study provide a new perspective on the complex mechanisms utilized by S. aureus during the establishment of infections.

RevDate: 2020-01-15

Yuan Z, Dai Y, Ouyang P, et al (2020)

Thymol Inhibits Biofilm Formation, Eliminates Pre-Existing Biofilms, and Enhances Clearance of Methicillin-Resistant Staphylococcus aureus (MRSA) in a Mouse Peritoneal Implant Infection Model.

Microorganisms, 8(1): pii:microorganisms8010099.

Methicillin-resistant Staphylococcus aureus (MRSA) is a common human pathogen that causes several difficult-to-treat infections, including biofilm-associated infections. The biofilm-forming ability of S. aureus plays a pivotal role in its resistance to most currently available antibiotics, including vancomycin, which is the first-choice drug for treating MRSA infections. In this study, the ability of thymol (a monoterpenoid phenol isolated from plants) to inhibit biofilm formation and to eliminate mature biofilms, was assessed. We found that thymol could inhibit biofilm formation and remove mature biofilms by inhibiting the production of polysaccharide intracellular adhesin (PIA) and the release of extracellular DNA (eDNA). However, cotreatment with thymol and vancomycin was more effective at eliminating MRSA biofilms, in a mouse infection model, than monotherapy with vancomycin. Comparative histopathological analyses revealed that thymol reduced the pathological changes and inflammatory responses in the wounds. Assessments of white blood cell counts and serum TNF-α and IL-6 levels showed reduced inflammation and an increased immune response following treatment with thymol and vancomycin. These results indicate that combinatorial treatment with thymol and vancomycin has the potential to serve as a more effective therapy for MRSA biofilm-associated infections than vancomycin monotherapy.

RevDate: 2020-01-15

Cui L, Wang X, Huang D, et al (2020)

CRISPR-cas3 of Salmonella Upregulates Bacterial Biofilm Formation and Virulence to Host Cells by Targeting Quorum-Sensing Systems.

Pathogens (Basel, Switzerland), 9(1): pii:pathogens9010053.

Salmonella is recognized as one of the most common microbial pathogens worldwide. The bacterium contains the clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) systems, providing adaptive immunity against invading foreign nucleic acids. Previous studies suggested that certain bacteria employ the Cas proteins of CRISPR-Cas systems to target their own genes, which also alters the virulence during invasion of mammals. However, whether CRISPR-Cas systems in Salmonella have similar functions during bacterial invasion of host cells remains unknown. Here, we systematically analyzed the genes that are regulated by Cas3 in a type I-E CRISPR-Cas system and the virulence changes due to the deletion of cas3 in Salmonella enterica serovar Enteritidis. Compared to the cas3 gene wild-type (cas3 WT) Salmonella strain, cas3 deletion upregulated the lsrFGBE genes in lsr (luxS regulated) operon related to quorum sensing (QS) and downregulated biofilm-forming-related genes and Salmonella pathogenicity island 1 (SPI-1) genes related to the type three secretion system (T3SS). Consistently, the biofilm formation ability was downregulated in the cas3 deletion mutant (Δcas3). The bacterial invasive and intracellular capacity of Δcas3 to host cells was also reduced, thereby increasing the survival of infected host cells and live chickens. By the transcriptome-wide screen (RNA-Seq), we found that the cas3 gene impacts a series of genes related to QS, the flagellum, and SPI-1-T3SS system, thereby altering the virulence phenotypes. As QS SPI-1-T3SS and CRISPR-Cas systems are widely distributed in the bacteria kingdom, our findings extend our understanding of virulence regulation and pathogenicity in mammalian hosts for Salmonella and potentially other bacteria.

RevDate: 2020-01-14

Wang J, Peng X, Yin W, et al (2020)

Eradication of Microorganisms Embedding in Biofilm by a Dose-Dependent Urokinase-Based Catheter Lock Solution in Chronic Hemodialysis Patients.

Blood purification pii:000505566 [Epub ahead of print].

INTRODUCTION: Catheter-related blood stream infection (CRBSI), the most common complication of central vein catheter (CVC), was closely associated with high morbidity and mortality in hemodialysis (HD) patients. Conjunction with systemic antibiotic, antibiotic lock (ABL) is an important therapeutic option to salvage the catheter. With extra antimicrobial and biofilm removing properties, urokinase plasminogen activator (uPA)-based ABL could have a potential role in the treatment of CRBSI.

OBJECTIVE: In this study, we aimed to explore effectiveness of uPA-based (ABL) on microorganisms embedded in biofilms in vitro and CVC salvage rate in HD patients with CRBSI.

METHODS: In vitro, we induced biofilms formation on the surface of HD catheter by mimicking the development of CRBSI. Applying uPA with or without antibiotics on the kinds of microorganism biofilms to explore its antimicrobial and biofilm removing properties. In vivo, 86 HD patients diagnosed as CRBSI were retrospectively enrolled to see effectiveness of uPA-based ABL on catheter salvage rate as compare to heparin-based ABL.

RESULTS: uPA was effect to Staphylococcus epidermidis biofilms compared to Staphylococcus aureus, Escherichia coli, and Candida albicans. Less biofilm residues made the regrowth of S. epidermidis also limited. The combination of uPA with antibiotic showed better antimicrobial and antibiofilm activity than uPA alone or heparin-based ABL in vitro and in vivo. Among HD patients, uPA-based ABL did not cause any obvious adverse affects, and it was more effective in treating coagulase-negative Staphylococci related CRBSI than other microorganisms.

CONCLUSIONS: The combination of uPA and a therapeutic plasma concentration of sensitive antibiotic can work together to effectively remove coagulase-negative S. epidermidis embedded in biofilms in vitro. uPA-based ABL is safe and effective therapeutic intervention for HD patients with CRBSI, especially compared to heparin-based ABL.

RevDate: 2020-01-14

Barilli E, Vismarra A, Frascolla V, et al (2020)

Escherichia coli Strains Isolated from Retail Meat Products: Evaluation of Biofilm Formation Ability, Antibiotic Resistance, and Phylogenetic Group Analysis.

Journal of food protection [Epub ahead of print].

Escherichia coli is a ubiquitous organism capable of forming a biofilm. This is an important virulence factor and is critical in certain diseases and in the development of antibiotic resistance, which is increased by biofilm synthesis. In the present study, the potential health risk associated with handling and consumption of foods of animal origin contaminated with E. coli-producing biofilm was evaluated. We analyzed the ability of 182 E. coli strains isolated from pork, poultry, and beef, purchased in three different supermarkets in the area of the "Italian Food Valley" (Parma, northern Italy), to form biofilms. Positive strains were also tested for the presence of 12 biofilm-associated genes. Moreover, the 182 E. coli were characterized for antibiotic resistance, presence of multidrug resistance, extended-spectrum β-lactamase strains, and phylogenetic diversity through PCR. Twenty-five percent of the isolates produced biofilm. The majority showed weak adherence, five were moderate, and three were strong producers. E. coli with a strong adherence capability (three of three) harbored eight biofilm-associated genes, while weak and moderate producers harbored only five (frequencies ranging from 80 to 100%). Multidrug resistance was observed in 20 biofilm-producing E. coli, and 15 of these belonged to phylogenetic group D. Among nonbiofilm producers, the percentage of strains belonging to phylogenetic groups B2 and D was approximately 40%, highlighting a potential health risk for consumers and people handling contaminated products. The present study underlines the importance of monitoring the prevalence and characteristics of E. coli contaminating retail meat in relation to the potential virulence highlighted here.

RevDate: 2020-01-14

Li J, Zhong W, Zhang K, et al (2020)

Biguanide-Derived Polymeric Nanoparticles Kill MRSA Biofilm and Suppress Infection In Vivo.

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

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of drug-resistant infections. Its propensity to develop biofilms makes it especially resistant to conventional antibiotics. We present a novel nanoparticle (NP) system made from biocompatible F -127 surfactant, t annic acid (TA), and biguanide-based p olymetformin (PMET) (termed FTP NPs), which can kill MRSA biofilm bacteria effectively in vitro and in vivo and which has excellent biocompatibility. FTP NPs exhibit biofilm bactericidal activity-ability to kill bacteria both inside and outside biofilm-significantly better than many antimicrobial peptides or polymers. At low concentrations (8-32 μg/mL) in vitro, FTP NPs outperformed PMET with ∼100-fold (∼2 log10) greater reduction of MRSA USA300 biofilm bacterial cell counts, which we attribute to the antifouling property of the hydrophilic poly(ethylene glycol) contributed by F-127. Further, in an in vivo murine excisional wound model, FTP NPs achieved 1.8 log10 reduction of biofilm-associated MRSA USA300 bacteria, which significantly outperformed vancomycin (0.8 log10 reduction). Moreover, in vitro cytotoxicity tests showed that FTP NPs have less toxicity than PMET toward mammalian cells, and in vivo intravenous injection of FTP NPs at 10 mg/kg showed no acute toxicity to mice with negligible body weight loss and no significant perturbation of blood biomarkers. These biguanide-based FTP NPs are a promising approach to therapy of MRSA infections.

RevDate: 2020-01-17

Thöming JG, Tomasch J, Preusse M, et al (2020)

Parallel evolutionary paths to produce more than one Pseudomonas aeruginosa biofilm phenotype.

NPJ biofilms and microbiomes, 6:2.

Studying parallel evolution of similar traits in independent within-species lineages provides an opportunity to address evolutionary predictability of molecular changes underlying adaptation. In this study, we monitored biofilm forming capabilities, motility, and virulence phenotypes of a plethora of phylogenetically diverse clinical isolates of the opportunistic pathogen Pseudomonas aeruginosa. We also recorded biofilm-specific and planktonic transcriptional responses. We found that P. aeruginosa isolates could be stratified based on the production of distinct organismal traits. Three major biofilm phenotypes, which shared motility and virulence phenotypes, were produced repeatedly in several isolates, indicating that the phenotypes evolved via parallel or convergent evolution. Of note, while we found a restricted general response to the biofilm environment, the individual groups of biofilm phenotypes reproduced biofilm transcriptional profiles that included the expression of well-known biofilm features, such as surface adhesive structures and extracellular matrix components. Our results provide insights into distinct ways to make a biofilm and indicate that genetic adaptations can modulate multiple pathways for biofilm development that are followed by several independent clinical isolates. Uncovering core regulatory pathways that drive biofilm-associated growth and tolerance towards environmental stressors promises to give clues to host and environmental interactions and could provide useful targets for new clinical interventions.

RevDate: 2020-01-14

Le TN, CK Lee (2020)

Surface Functionalization of Poly(N-Vinylpyrrolidone) onto Poly(Dimethylsiloxane) for Anti-Biofilm Application.

Applied biochemistry and biotechnology pii:10.1007/s12010-020-03238-5 [Epub ahead of print].

Poly(dimethylsiloxane) (PDMS) has been widely used in the field of microfluidics, optical systems, and sensors. However, the hydrophobic nature of PDMS leads to low surface wettability and biofouling problems due to the nonspecific proteins-hydrophobic surface interactions and cell/bacterial adhesion. In this work, the PDMS surface was first introduced with amino groups (PDMS-NH2) via KOH-catalyzed reaction with 3-aminopropyltriethoxysilane (APTES). The PDMS-NH2 was then grafted with poly(N-vinylpyrrolidone) (PVP) based on the self-adhesion reaction between the amino surface and catechol-functionalized PVP (CA-PLL-PVP). CA-PLL-PVP as a comb-polymer was synthesized by conjugating PVP-COOH along with caffeic acid to the ε-polylysine backbone. A significantly enhanced water wettability was observed with contact angles dropped from 116° to 14° after coating with CA-PLL-PVP. The coated surface demonstrated excellent antifouling performance that no appreciable Staphylococcus epidermidis biofilm formation could be observed. This novel facile antifouling coating on PDMS surface may find greater biomedical applications to eliminate the potential adherence problems caused by natural biofouling.

RevDate: 2020-01-14

Jin Y, Guo Y, Zhan Q, et al (2020)

Sub-Inhibitory Concentrations of Mupirocin Stimulate Staphylococcus aureus Biofilm Formation by Up-regulating cidA.

Antimicrobial agents and chemotherapy pii:AAC.01912-19 [Epub ahead of print].

Previous studies have shown that the administration of antibiotics at sub-inhibitory concentrations stimulates biofilm formation by the majority of MRSA strains. Here, we investigated the effect of sub-inhibitory mupirocin concentrations on biofilm formation by the community-associated (CA) mupirocin-sensitive MRSA strain USA300 and highly mupirocin-resistant clinical S. aureus SA01-SA05 isolates. We found that mupirocin increased the ability of MRSA cells to attach to surfaces and form biofilms. Confocal laser scanning microscopy (CLSM) demonstrated that mupirocin treatment promoted thicker biofilm formation, which also correlated with the production of extracellular DNA (eDNA). Furthermore, RT-qPCR results revealed that this effect was largely due to the involvement of holin-/antiholin-like proteins (encoded by the cidA gene), which are responsible for modulating cell death and lysis during biofilm development. We found that cidA expression levels significantly increased 6.05-35.52 fold (P < 0.01) on mupirocin administration. We generated a cidA-deficient mutant of the USA300 S. aureus strain. Exposure of the ΔcidA mutant to mupirocin did not result in thicker biofilm formation compared with that in the parent strain. We therefore hypothesize that the mupirocin-induced stimulation of S. aureus biofilm formation may involve the upregulation of cidA.

RevDate: 2020-01-14

Kimbrough JH, Cribbs JT, LL McCarter (2020)

Homologous c-di-GMP-binding Scr transcription factors orchestrate biofilm development in Vibrio parahaemolyticus.

Journal of bacteriology pii:JB.00723-19 [Epub ahead of print].

The marine bacterium and human pathogen Vibrio parahaemolyticus rapidly colonizes surfaces by using swarming motility and forming robust biofilms. Entering either colonization program, swarming motility or sessility, involves differential regulation of many genes resulting in a dramatic shift in physiology and behavior. V. parahaemolyticus has evolved complex regulation to control these two processes that have opposing outcomes. One mechanism relies on the balance of the second messenger c-di-GMP: high c-di-GMP favors biofilm formation. V. parahaemolyticus possesses four homologous regulators, the Scr transcription factors, that belong in a Vibrio-specific family of W[F/L/M][T/S]R-motif transcriptional regulators, some members of which have been demonstrated to bind c-di-GMP. In this work, we explore the role of these Scr regulators in biofilm development. We show each protein binds c-di-GMP; this binding requires a critical R in the binding motif; and the biofilm-relevant activities of CpsQ, CpsS, and ScrO, but not ScrP are dependent upon second messenger binding. ScrO and CpsQ are the primary drivers of biofilm formation: biofilms are eliminated when both of these regulators are absent. ScrO is most important for capsule expression. CpsQ is most important for RTX-matrix protein expression, although it contributes to capsule expression when c-di-GMP is high. Both regulators contribute to O-antigen ligase expression. ScrP works oppositely in a minor role to repress the ligase gene. CpsS plays a regulatory checkpointing role by negatively modulating expression of these biofilm-pertinent genes under fluctuating c-di-GMP conditions. Our work further elucidates the multifactorial network that contributes to biofilm development in V. parahaemolyticusImportanceVibrio parahaemolyticus can inhabit open ocean, chitinous shells, and the human gut. Such varied habitats and the transitions between them require adaptable regulatory networks controlling energetically expensive behaviors including swarming motility and biofilm formation, which are promoted by low and high concentrations of the signaling molecule c-di-GMP, respectively. Here, we describe four homologous c-di-GMP-binding Scr transcription factors in V. parahaemolyticus Members of this family of regulators are present in many vibrios, yet their number and the nature of their activities differ across species. Our work highlights the distinctive roles that these transcription factors play in dynamically controlling biofilm formation and architecture in V. parahaemolyticus and serves as a powerful example of regulatory network evolution and diversification.

RevDate: 2020-01-20

Paniagua AT, Paranjape K, Hu M, et al (2019)

Impact of temperature on Legionella pneumophila, its protozoan host cells, and the microbial diversity of the biofilm community of a pilot cooling tower.

The Science of the total environment, 712:136131 pii:S0048-9697(19)36127-3 [Epub ahead of print].

Legionella pneumophila is a waterborne bacterium known for causing Legionnaires' Disease, a severe pneumonia. Cooling towers are a major source of outbreaks, since they provide ideal conditions for L. pneumophila growth and produce aerosols. In such systems, L. pneumophila typically grow inside protozoan hosts. Several abiotic factors such as water temperature, pipe material and disinfection regime affect the colonization of cooling towers by L. pneumophila. The local physical and biological factors promoting the growth of L. pneumophila in water systems and its spatial distribution are not well understood. Therefore, we built a lab-scale cooling tower to study the dynamics of L. pneumophila colonization in relationship to the resident microbiota and spatial distribution. The pilot was filled with water from an operating cooling tower harboring low levels of L. pneumophila. It was seeded with Vermamoeba vermiformis, a natural host of L. pneumophila, and then inoculated with L. pneumophila. After 92 days of operation, the pilot was disassembled, the water was collected, and biofilm was extracted from the pipes. The microbiome was studied using 16S rRNA and 18S rRNA genes amplicon sequencing. The communities of the water and of the biofilm were highly dissimilar. The relative abundance of Legionella in water samples reached up to 11% whereas abundance in the biofilm was extremely low (≤0.5%). In contrast, the host cells were mainly present in the biofilm. This suggests that L. pneumophila grows in host cells associated with biofilm and is then released back into the water following host cell lysis. In addition, water temperature shaped the bacterial and eukaryotic community of the biofilm, indicating that different parts of the systems may have different effects on Legionella growth.

RevDate: 2020-01-13

Britt NS, Hazlett DS, Horvat RT, et al (2020)

Activity of Pulmonary Vancomycin Exposures versus Planktonic and Biofilm Methicillin-Resistant Staphylococcus aureus Isolated from Cystic Fibrosis Sputum.

International journal of antimicrobial agents pii:S0924-8579(20)30037-6 [Epub ahead of print].

Vancomycin is commonly used to treat methicillin-resistant Staphylococcus aureus (MRSA) infection in patients with cystic fibrosis (CF) lung disease; however, there are limited data to support the in vitro activity of this agent against MRSA isolated from CF sputum. The primary objective of this study was to evaluate the activity of vancomycin at pulmonary concentrations (intravenous and inhaled) against 4 clinical MRSA CF sputum isolates in planktonic and biofilm time-kill (TK) experiments. Vancomycin minimum inhibitory concentrations (MICs) were determined for these isolates at standard inoculum (SI; ∼106 colony-forming units [CFU]/mL) and high inoculum (HI; ∼108 CFU/mL), and in biofilms cultivated using physiologic media recapitulating the microenvironment of the CF lung. Vancomycin concentrations of 10, 25, 100, and 275 µg/mL were evaluated in TK experiments against planktonic MRSA at varying inocula and versus biofilm MRSA. Vancomycin MICs increased from 0.5 µg/mL at SI to 8-16 µg/mL when tested at HI. Vancomycin MICs were further increased to 16-32 µg/mL in biofilm studies. In TK experiments, vancomycin displayed bactericidal activity (≥ 3 log10 killing at 24 h) against 1/4 and 0/4 planktonic MRSA isolates at SI and HI, respectively. Against MRSA biofilms, vancomycin was bactericidal against 0/4 isolates. Based on these findings, vancomycin monotherapy appears unlikely to eradicate MRSA from the respiratory tract of patients with CF, even at high concentrations similar to those observed with inhaled therapy. Novel vancomycin formulations with enhanced biofilm penetration or combination therapy with other potentially synergistic agents should be explored.

RevDate: 2020-01-20

Thinakaran S, Loordhuswamy A, G Venkateshwapuram Rengaswami (2020)

Electrophoretic deposition of chitosan/nano silver embedded micro sphere on centrifugal spun fibrous matrices - A facile biofilm resistant biocompatible material.

International journal of biological macromolecules, 148:68-78 pii:S0141-8130(19)33425-7 [Epub ahead of print].

Micro fibrous polycaprolactone (PCL) mat generally used for biomedical application was produced by facile centrifugal spinning system (C-Spin). The produced mat exhibited good structural integrity and good flexibility. The developed mat was used as substrate for electrophoretic deposition (EPD) of chitosan and polyethylene glycol (PEG) along with silver nano particles (AgNPs). During the EPD process, polymeric micro spheres embedded with silver nano particles were formed and deposited on the C-Spun substrates and the size of AgNPs were found to be around 15 nm. Surface topography of all coated samples were analyzed and found that the deposition was neat and uniform. Swelling behavior of the coated substrates were studied and found that CS/HMP/AgNPs coated substrates showed 274% swelling compared to their own dry weight. Release profile of silver nanoparticles confirmed that initial burst release followed by sustained release for CS/HMP/AgNPs coated substrates and this might be attributed to the hydrophilicity and high swellability of HMP. All AgNPs coated samples were completely prevent the bacterial biofilm formation and CS/HMP/AgNPs showed better reduction in bacterial growth on matured biofilm model. Cell proliferation studies confirmed that CS/HMP/AgNPs is biocompatible and can be used as a wound dressing material.

RevDate: 2020-01-17

Lucio-Sauceda DG, Urrutia-Baca VH, Gomez-Flores R, et al (2019)

Antimicrobial and Anti-Biofilm Effect of an Electrolyzed Superoxidized Solution at Neutral-pH against Helicobacter pylori.

BioMed research international, 2019:6154867.

The presence of Helicobacter pylori in the oral cavity has been associated to the failure of antimicrobial therapy in patients with gastrointestinal infection and the development of oral diseases. However, it has been reported that the maintenance of good oral hygiene can improve the therapeutic success rates, where the use of mouthwashes with anti-Helicobacter activity would help to achieve it. The aim was to evaluate the antimicrobial activity of OxOral® mouthwash against H. pylori and its effect on biofilm formation. The minimum inhibitory concentration (MIC) of OxOral® (pH = 6.4-7.5, ORP = 650-900 mV) against H. pylori was calculated testing serial dilutions 0.117-15 ppm against 1 × 108 CFU/mL of H. pylori (ATCC® 700824™) by broth microdilution method using 96-well plates. The H. pylori biofilm formation was determined by the optical density measurement at 600 nm from coverslips stained with 0.1% crystal violet. The gene expression of ureA, luxS, flaA, omp18, and lpxD were analyzed by RT-qPCR. OxOral® cytotoxicity was evaluated in a human gingival fibroblast cell line by MTT assay. MIC was of 3.75 ppm, with 99.7 ± 7.7% bacterial growth inhibition. In the negative control, the biofilm formation was observed, whereas when bacteria were treated with OxOral® at 0.234, 0.469, and 0.938 ppm, an inhibition of 35.5 ± 0.9%, 89.1 ± 1.2%, and 99.9 ± 5.5% were obtained, respectively. The gene expression analysis showed that flaA, omp18, and lpxD genes were down-regulated with OxOral® compared with control (p < 0.05). Low cytotoxicity of 16.5 ± 7.6% was observed at the highest dose (15 ppm); no significant differences were observed from 15 to 0.469 ppm compared to the control of untreated cells (p > 0.05). Our results reveal an important anti-Helicobacter activity of OxOral® and open the possibility of its therapeutic use new studies, which would increase the success rate of conventional therapies against H. pylori.

RevDate: 2020-01-17

Avila-Novoa MG, Solís-Velázquez OA, Rangel-López DE, et al (2019)

Biofilm Formation and Detection of Fluoroquinolone- and Carbapenem-Resistant Genes in Multidrug-Resistant Acinetobacter baumannii.

The Canadian journal of infectious diseases & medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale, 2019:3454907.

Acinetobacter baumannii is an important opportunistic pathogen that shows resistance to cephalosporins, penicillins, carbapenems, fluoroquinolones, and aminoglycosides, the multiresistance being associated with its ability to form biofilms in clinical environments. The aim of this study was to determine biofilm formation and its potential association with genes involved in antibiotic resistance mechanisms of A. baumannii isolates of different clinical specimens. We demonstrated 100% of the A. baumannii isolates examined to be multidrug resistant (MDR), presenting a 73.3% susceptibility to cefepime and a 53.3% susceptibility to ciprofloxacin. All A. baumannii isolates were positive for blaOXA-51, 33.3% being positive for blaOXA-23 and ISAba1, and 73.3% being positive for gyrA. We found 86.6% of A. baumannii strains to be low-grade biofilm formers and 13.3% to be biofilm negative; culturing on Congo red agar (CRA) plates revealed that 73.3% of the A. baumannii isolates to be biofilm producers, while 26.6% were not. These properties, combined with the role of A. baumannii as a nosocomial pathogen, increase the probability of A. baumannii causing nosocomial infections and outbreaks as a complication during therapeutic treatments and emphasize the need to control A. baumannii biofilms in hospital environments.

RevDate: 2020-01-13

Obata O, Salar-Garcia MJ, Greenman J, et al (2020)

Development of efficient electroactive biofilm in urine-fed microbial fuel cell cascades for bioelectricity generation.

Journal of environmental management, 258:109992 pii:S0301-4797(19)31710-4 [Epub ahead of print].

The Microbial fuel cell (MFC) technology harnesses the potential of some naturally occurring bacteria for electricity generation. Digested sludge is commonly used as the inoculum to initiate the process. There are, however, health hazards and practical issues associated with the use of digested sludge depending on its origin as well as the location for system deployment. This work reports the development of an efficient electroactive bacterial community within ceramic-based MFCs fed with human urine in the absence of sludge inoculum. The results show the development of a uniform bacterial community with power output levels equal to or higher than those generated from MFCs inoculated with sludge. In this case, the power generation begins within 2 days of the experimental set-up, compared to about 5 days in some sludge-inoculated MFCs, thus significantly reducing the start-up time. The metagenomics analysis of the successfully formed electroactive biofilm (EAB) shows significant shifts between the microbial ecology of the feeding material (fresh urine) and the developed anodic biofilm. A total of 21 bacteria genera were detected in the urine feedstock whilst up to 35 different genera were recorded in the developed biofilm. Members of Pseudomonas (18%) and Anaerolineaceae (17%) dominate the bacterial community of the fresh urine feed while members of Burkholderiaceae (up to 50%) and Tissierella (up to 29%) dominate the anodic EAB. These results highlight a significant shift in the bacterial community of the feedstock towards a selection and adaptation required for the various electrochemical reactions essential for survival through power generation.

RevDate: 2020-01-13

Trojanowicz K, E Plaza (2020)

Combining numerical simulation with response surface modelling for optimization of reject water partial nitritation/anammox in moving bed biofilm reactor.

Environmental technology [Epub ahead of print].

Optimization of a single-stage, partial nitritation/anammox (PN/A) process for a reject water treatment in a continuous-flow, moving bed biofilm reactor (MBBR) was presented. Response surface methodology (RSM) was combined with simulation experiments conducted with the validated mathematical model of PN/A in MBBR. The total inorganic nitrogen (TIN) removal efficiency was the response parameter. Eight independent variables were taken into examination: reject water flow rate (Q), inflow concentrations of the total ammonium nitrogen (TAN), chemical oxygen demand (COD), alkalinity (ALK), pH, temperature (T), dissolved oxygen concentration in the bulk liquid (DO) and aeration time within 60 minutes intermittent aeration cycle (AERON). Eleven interactions between independent variables were found as significant (p < 0.05). The interaction of AERON*DO had the highest impact on PN/A process. Optimal values of the controlled variables were found for two cases of MBBR operation. Verification of the optimization was done by simulation and comparison with the data from the empirical experiments. Under conditions of the fixed hydraulic retention time of about 38 hours, volumetric nitrogen loading rate of 0.48 gN/m3d, T of 22.5°C, TAN of 750 gN/m3 and optimized values of DO = 3.0 gO2/m3, AERON = 0.54 hour, pH = 7.5, ALK = 80 molHCO3/m3, COD = 775 gO2/m3, the predicted TINrem was 78% which is consistent with PN/A performance observed in the technical-scale MBBR systems.

RevDate: 2020-01-13

Liu C, Zhu L, L Chen (2020)

Mechanism of biofilm formation on a hydrophobic polytetrafluoroethylene membrane during the purification of surface water using direct contact membrane distillation (DCMD), with especial interest in the feed properties.

Biofouling [Epub ahead of print].

The impact of feed water quality on biofilm formation during membrane distillation (MD) was investigated in this study, particularly emphasizing the interrelationship between organics, salts, and microbes. Two types of typical natural surface waters in Nanjing, China, were chosen as feed solutions for long-term MD operation, including the Qinhuai River and Xuanwu Lake. The biofilms that developed under different feed water qualities exhibited distinct Foulant compositions and structures, causing different flux decline trends for the MD system. Accordingly, two typical patterns of biofilm formation were suggested for the MD operation of the two different kinds of surface waters in this study. Organics from a primal feed solution and dead bacteria were the key to the establishment of a biofilm on the membrane, and this needs to be effectively removed from the MD system through pre-treatment and process control strategies. Finally, a feasible strategy for MD biofouling control was suggested.

RevDate: 2020-01-13

Dong H, Zhang W, Wang Y, et al (2020)

Biofilm polysaccharide display platform: A natural, renewable, and biocompatible material for improved lipase performance.

Journal of agricultural and food chemistry [Epub ahead of print].

Most of microorganisms can form biofilms, which makes biofilms become an abundant bioresource to be exploited. Due to the application limitations of current immobilization methods onto biofilms, we developed an immobilization method called the Biofilm Polysaccharides Display (BPD) strategy while maintaining the native biofilm structure and catalytic microenvironment of C. acetobutylicum B3. Lipase Lip181 showed significant improvements in stability after chemical immobilization. For example, immobilized Lip181 retained 74.23% of its original activity after incubation for 14 days while free Lip181 was totally deactivated. In addition, immobilized Lip181 maintained high residual activity (pH 5.0pH 11.0), which showed improved resistance to pH changes. Notably, this method did not decrease but slightly increased the relative activity of Lip181 from 6.39 to 6.78 U/mg. Immobilized Lip181 was used to prepare cinnamyl acetate, and it showed a maximum yield of 85.09%. Overall, this biofilm immobilization method may promote the development of biocatalysis and biofilm materials.

RevDate: 2020-01-13

Paluch E, Rewak-Soroczyńska J, Jędrusik I, et al (2020)

Prevention of biofilm formation by quorum quenching.

Applied microbiology and biotechnology pii:10.1007/s00253-020-10349-w [Epub ahead of print].

Quorum sensing (QS) is a mechanism that enables microbial communication. It is based on the constant secretion of signaling molecules to the environment. The main role of QS is the regulation of vital processes in the cell such as virulence factor production or biofilm formation. Due to still growing bacterial resistance to antibiotics that have been overused, it is necessary to search for alternative antimicrobial therapies. One of them is quorum quenching (QQ) that disrupts microbial communication. QQ-driving molecules can decrease or even completely inhibit the production of virulence factors (including biofilm formation). There are few QQ strategies that comprise the use of the structural analogues of QS receptor autoinductors (AI). They may be found in nature or be designed and synthesized via chemical engineering. Many of the characterized QQ molecules are enzymes with the ability to degrade signaling molecules. They can also impede cellular signaling cascades. There are different techniques used for testing QS/QQ, including chromatography-mass spectroscopy, bioluminescence, chemiluminescence, fluorescence, electrochemistry, and colorimetry. They all enable qualitative and quantitative measurements of QS/QQ molecules. This article gathers the information about the mechanisms of QS and QQ, and their effect on microbial biofilm formation. Basic methods used to study QS/QQ, as well as the medical and biotechnological applications of QQ, are also described. Basis research methods are also described as well as medical and biotechnological application.

RevDate: 2020-01-13

Akoğlu A (2020)

The effect of some environmental conditions on planktonic growth and biofilm formation by some lactic acid bacteria isolated from a local cheese in Turkey.

Biotechnology letters pii:10.1007/s10529-020-02794-4 [Epub ahead of print].

OBJECTIVE: The purpose of this study was to determine the effect of some environmental conditions (different temperature degrees and pH values, different salt, glucose and lactose concentrations) on the planktonic growth and biofilm formation ability of the lactic acid bacteria (LAB) isolated from a local cheese in Turkey.

RESULTS: It was determined that Enterococcus lactis EC61 and Enterococcus faecalis EC41 are the most resistant bacteria to the changing environmental conditions and they can stably maintain their planktonic growth in the pH values of 6.5, 7.0, 7.5, and 8.0; in the salt concentrations of 4% and 6.5%; in the glucose concentration of 0.5%; and in the lactose concentrations of 0.5%, 1.5%, and 2.5%. It was found that all strains had the biofilm formation ability and especially the biofilm formation of Enterococcus lactis EC61 and Enterococcus faecalis EC41 strains significantly increased in the acidic pH values and in the increasing glucose and lactose concentrations, and significantly decreased in the increasing salt concentration.

CONCLUSIONS: When considered in terms of LAB potential as a starter culture, specifying the effect of some environmental conditions on the planktonic growth and biofilm formation ability is important for the food industry. As a conclusion, it was determined that lactic acid bacteria, which were previously determined to have some starter culture characteristics, had additional properties on the way to being an starter culture.

RevDate: 2020-01-13

Hasan ME, Shahriar A, Shams F, et al (2020)

Correlation between biofilm formation and antimicrobial susceptibility pattern toward extended spectrum β-lactamase (ESBL)- and non-ESBL-producing uropathogenic bacteria.

Journal of basic and clinical physiology and pharmacology pii:/j/jbcpp.ahead-of-print/jbcpp-2019-0296/jbcpp-2019-0296.xml [Epub ahead of print].

Background Urinary tract infections (UTIs) are the most common bacterial infection encountered worldwide and are associated with significant morbidity and mortality. Methods The present study was undertaken to investigate the biofilm-forming ability, antibiotic susceptibility patterns and extended spectrum β-lactamase (ESBL) production of seven uropathogenic isolates comprising both Escherichia coli and Klebsiella pneumoniae. The morphological, cultural and biochemical tests for the identification of the isolates, antibiotic susceptibility test, detection of ESBL production, biofilm formation on 96-well microtiter plate and Congo red agar (CRA) media are performed. Results The antimicrobial susceptibility profiles obtained in this study showed that the most active drugs gentamicin, amikacin and imipenem (100% sensitivity) were followed by amoxicillin-clavulanic acid (85% sensitivity), co-trimoxazole, ciprofloxacin (57% sensitivity) ceftazidime and kanamycin (50% sensitivity). All the isolates showed resistance to amoxicillin followed by ceftriaxone and cefotaxime (71% resistance), and the scenario gets more complicated because of the production of ESBL by five isolates (three E. coli isolates and two K. pneumoniae). The strains were also able to form biofilm as tested on CRA medium and by microtiter plate assay. The correlation between ESBL, non-ESBL and biofilm-producing E. coli and K. pneumonia was determined along with the multiple drug resistance patterns of E. coli and K. pneumonia. Conclusions The findings of the study indicate that the emergence and rapid spread of such multidrug-resistant pathogens are of great concern. Early detection of ESBL-producing pathogen is of paramount clinical importance; therefore, strict infection control practices as well as therapeutic guidance for confirmed infection can be rapidly initiated.

RevDate: 2020-01-11

Suleiman M, Schröder C, Kuhn M, et al (2019)

Microbial biofilm formation and degradation of octocrylene, a UV absorber found in sunscreen.

Communications biology, 2(1):430 pii:10.1038/s42003-019-0679-9.

Octocrylene is a widely used synthetic UV absorber of sunscreens and found in several environments. Ecological consequences of the accumulation of UV filters are widely discussed. This is the first report revealing the microbial potential to transform octocrylene. A microbial community comprising four bacterial species was enriched from a landfill site using octocrylene as carbon source. From these microorganisms Mycobacterium agri and Gordonia cholesterolivorans were identified as most potent applying a new "reverse discovery" approach. This relies on the possibility that efficient strains that are already isolated and deposited can be identified through enrichment cultures. These strains formed massive biofilms on the octocrylene droplets. GC-MS analysis after cultivation for 10 days with M. agri revealed a decrease in octocrylene concentration of 19.1%. LC-MS/MS analysis was utilized in the detection and quantification of transformation products of octocrylene. M. agri thus represents an ideal candidate for bioremediation studies with octocrylene and related compounds.

RevDate: 2020-01-15

Kamali E, Jamali A, Ardebili A, et al (2020)

Evaluation of antimicrobial resistance, biofilm forming potential, and the presence of biofilm-related genes among clinical isolates of Pseudomonas aeruginosa.

BMC research notes, 13(1):27.

OBJECTIVES: Pseudomonas aeruginosa is known as a leading cause of nosocomial infections worldwide. Antimicrobial resistance and biofilm production, as two main virulence factors of P. aeruginosa, are responsible for the persistence of prolonged infections. In this study, antimicrobial susceptibility pattern and phenotypic and genotypic characteristics of biofilm of P. aeruginosa were investigated.

RESULTS: A total of 80 clinical P. aeruginosa isolates were obtained. Isolates showed resistance to all antibiotics with a rate from 12.5% (n = 10) against amikacin and piperacillin/tazobactam to 23.75% (n = 19) to levofloxacin. Multidrug-resistant P. aeruginosa accounted for 20% (n = 16). 83.75% (n = 67) of isolates showed biofilm phenotype. All three biofilm-related genes were found simultaneously in 87.5% (n = 70) of P. aeruginosa and 13.5% (n = 10) of the isolates had none of the genes tested. From the results of the present study, combination therapy including an anti-pseudomonal beta-lactam (piperacillin/tazobactam or ceftazidime) and an aminoglycoside or carbapenems (imipenem, meropenem) with fluoroquinolones in conjunction with an aminoglycoside can be used against Pseudomonas infections. However, reasonable antimicrobial use and high standards of infection prevention and control are essential to prevent further development of antimicrobial resistance. Combination strategies based on the proper anti-pseudomonal antibiotics along with anti-biofilm agents can also be selected to eradicate biofilm-associated infections.

RevDate: 2020-01-11

Tan Y, Ma S, Leonhard M, et al (2020)

Co-immobilization of cellobiose dehydrogenase and deoxyribonuclease I on chitosan nanoparticles against fungal/bacterial polymicrobial biofilms targeting both biofilm matrix and microorganisms.

Materials science & engineering. C, Materials for biological applications, 108:110499.

Polymicrobial biofilm related infections have been a major threat in health care. In this study, the co-immobilization of cellobiose dehydrogenase (CDH) and deoxyribonuclease I (DNase) on positively charged chitosan nanoparticles (CSNPs) resulted in a bi-functional nanoparticle (CSNP-DNase-CDH) targeting both biofilm matrix and microorganisms. The in-vitro antibiofilm activities of CSNPs against monomicrobial and polymicrobial biofilms of Candida albicans and Staphylococcus aureus were evaluated. The results showed that CSNPs were able to penetrate across the matrix of biofilms and interfere with embedded microbial cells. CSNP-DNase-CDH exhibited a higher activity than CSNPs loaded with only DNase or CDH for inhibiting monomicrobial and polymicrobial biofilm formation as well as for disrupting pre-formed biofilms. Furthermore, CSNP-DNase-CDH could disrupt the biofilm formation through degradation of eDNA, reduce biofilm thickness, and kill microbial cells on silicone. The bi-functional CSNP is applicable for the protection of medical devices from polymicrobial biofilms or the treatment of device associated infections.

RevDate: 2020-01-11

Mahamuni-Badiger PP, Patil PM, Badiger MV, et al (2020)

Biofilm formation to inhibition: Role of zinc oxide-based nanoparticles.

Materials science & engineering. C, Materials for biological applications, 108:110319.

Zinc oxide nanoparticles have received much attention worldwide as they possess unique properties like varied morphology, large surface area to volume ratio, potent antibacterial activity, and biocompatibility. Biofilm contains homogenous or heterogeneous microorganisms that remain enclosed in a matrix of an extracellular polymeric substance on biotic or abiotic surfaces. Bacterial biofilm formed on medical devices such as central venous catheters, urinary catheters, prosthetic joints, cardiovascular implantable devices, dental implants, contact lenses, intrauterine contraceptive devices and breast implants cause persistent infections. Such biofilm-associated infections in medical implants cause serious problems for public health and affect the function of medical implants. So, there is an urgent need for the use of an antimicrobial agent that will inhibit biofilm, including such antibiotic-resistant bacterial strains as bacteria, to develop multiple drug-resistances resulting in failure of the antibiotic's action. The antimicrobial agent used should be ideal in terms of biocompatibility, antimicrobial activity, stability at different environmental conditions, with less sensitivity to the development of resistance towards micro-organisms, safe for in vivo and in vitro use, and remain non-hazardous to the environment, etc. The first objective of the review discusses the insights into the formation of biofilm on a medical device with the current strategies to inhibit. The second purpose is to review the recent progress in ZnO- based nanostructure including composites for antibacterial and anti-biofilm activities. This will offer a new opportunity for the application of Zinc oxide-based material in the prevention of biofilm on the medical devices.

RevDate: 2020-01-10

Elbourne A, Cheeseman S, Atkin P, et al (2020)

Antibacterial Liquid Metals: Biofilm Treatment via Magnetic Activation.

ACS nano [Epub ahead of print].

Antibiotic resistance has made the treatment of biofilm-related infections challenging. As such, the quest for next-generation antimicrobial technologies must focus on targeted therapies to which pathogenic bacteria cannot develop resistance. Stimuli-responsive therapies represent an alternative technological focus due to their capability of delivering targeted treatment. This study provides a proof-of-concept investigation into the use of magneto-responsive gallium-based liquid metal (LM) droplets as antibacterial materials, which can physically damage, disintegrate, and kill pathogens within a mature biofilm. Once exposed to a low-intensity rotating magnetic field, the LM droplets become physically actuated and transform their shape, developing sharp edges. When placed in contact with a bacterial biofilm, the movement of the particles resulting from the magnetic field, coupled with the presence of nanosharp edges, physically ruptures the bacterial cells and the dense biofilm matrix is broken down. The antibacterial efficacy of the magnetically activated LM particles was assessed against both Gram-positive and Gram-negative bacterial biofilms. After 90 min over 99% of both bacterial species became nonviable, and the destruction of the biofilms was observed. These results will impact the design of next-generation, LM-based biofilm treatments.

RevDate: 2020-01-13

Vergalito F, Pietrangelo L, Petronio Petronio G, et al (2018)

Vitamin E for Prevention of Biofilm-caused Healthcare-associated Infections.

Open medicine (Warsaw, Poland), 15:14-21.

The healthcare-associated infections (HCAIs) occur in patients both in nosocomial environments and in community. More often HCAIs are associated to the use of medical devices and bacterial biofilm development on these equipments. Due to the clinical and economic relevance of this topic, new strategies for the treatment of infections caused by biofilm proliferation are unceasingly searched by scientists. The present study investigated the role of vitamin E to reduce the biofilm formation for a larger panel of human pathogens, including strains of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Acinetobacter baumannii, Pseudomonas aeruginosa and Pseudomonas putida. This potential activity was tested by placing a preparation of vitamin E (α-Tocopheryl acetate) as interface between the bacterial culture and the polystyrene walls of a 96 well plate at different concentrations of glucose, used as a biofilm enhancer. The Staphylococcus genus was further investigated by spreading the vitamin E on a silicone catheter lumen and evaluating its influence on the bacterial colonization. From our results, vitamin E has been able to interfere with bacterial biofilm and prevent in vitro biofilm formation. Furthermore, the ability of Staphylococcus aureus and Staphylococcus epidermidis to colonize the catheter surface decreased as a result of vitamin E application.

RevDate: 2020-01-13

Ng HM, Slakeski N, Butler CA, et al (2019)

The Role of Treponema denticola Motility in Synergistic Biofilm Formation With Porphyromonas gingivalis.

Frontiers in cellular and infection microbiology, 9:432.

Chronic periodontitis has a polymicrobial biofilm etiology and interactions between key oral bacterial species, such as Porphyromonas gingivalis and Treponema denticola contribute to disease progression. P. gingivalis and T. denticola are co-localized in subgingival plaque and have been previously shown to exhibit strong synergy in growth, biofilm formation and virulence in an animal model of disease. The motility of T. denticola, although not considered as a classic virulence factor, may be involved in synergistic biofilm development between P. gingivalis and T. denticola. We determined the role of T. denticola motility in polymicrobial biofilm development using an optimized transformation protocol to produce two T. denticola mutants targeting the motility machinery. These deletion mutants were non-motile and lacked the gene encoding the flagellar hook protein of the periplasmic flagella (ΔflgE) or a component of the stator motor that drives the flagella (ΔmotB). The specificity of these gene deletions was determined by whole genome sequencing. Quantitative proteomic analyses of mutant strains revealed that the specific inactivation of the motility-associated gene, motB, had effects beyond motility. There were 64 and 326 proteins that changed in abundance in the ΔflgE and ΔmotB mutants, respectively. In the ΔflgE mutant, motility-associated proteins showed the most significant change in abundance confirming the phenotype change for the mutant was related to motility. However, the inactivation of motB as well as stopping motility also upregulated cellular stress responses in the mutant indicating pleiotropic effects of the mutation. T. denticola wild-type and P. gingivalis displayed synergistic biofilm development with a 2-fold higher biomass of the dual-species biofilms than the sum of the monospecies biofilms. Inactivation of T. denticola flgE and motB reduced this synergy. A 5-fold reduction in dual-species biofilm biomass was found with the motility-specific ΔflgE mutant suggesting that T. denticola periplasmic flagella are essential in synergistic biofilm formation with P. gingivalis.

RevDate: 2020-01-13

Durgadevi R, Abirami G, Alexpandi R, et al (2019)

Explication of the Potential of 2-Hydroxy-4-Methoxybenzaldehyde in Hampering Uropathogenic Proteus mirabilis Crystalline Biofilm and Virulence.

Frontiers in microbiology, 10:2804.

Proteus mirabilis is an important etiological agent of catheter-associated urinary tract infections (CAUTIs) owing to its efficient crystalline biofilm formation and virulence enzyme production. Hence, the present study explicated the antibiofilm and antivirulence efficacies of 2-hydroxy-4-methoxybenzaldehyde (HMB) against P. mirabilis in a non-bactericidal manner. HMB showed concentration-dependent biofilm inhibition, which was also evinced in light, confocal, and scanning electron microscopic (SEM) analyses. The other virulence factors such as urease, hemolysin, siderophores, and extracellular polymeric substances production as well as swimming and swarming motility were also inhibited by HMB treatment. Further, HMB treatment effectively reduced the struvite/apatite production as well as crystalline biofilm formation by P. mirabilis. Furthermore, the results of gene expression analysis unveiled the ability of HMB to impair the expression level of virulence genes such as flhB, flhD, rsbA, speA, ureR, hpmA, and hpmB, which was found to be in correlation with the results of in vitro bioassays. Additionally, the cytotoxicity analysis divulged the innocuous characteristic of HMB against human embryonic kidney cells. Thus, the present study reports the potency of HMB to act as a promising therapeutic remedy for P. mirabilis-instigated CAUTIs.

RevDate: 2020-01-13

Wang J, Jiao H, Meng J, et al (2019)

Baicalin Inhibits Biofilm Formation and the Quorum-Sensing System by Regulating the MsrA Drug Efflux Pump in Staphylococcus saprophyticus.

Frontiers in microbiology, 10:2800.

Staphylococcus saprophyticus (S. saprophyticus) is one of the main pathogens that cause serious infection due to its acquisition of antibiotic resistance. The efflux pump decreases antibiotic abundance, and biofilm compromises the penetration of antibiotics. It has been reported that baicalin is a potential agent to inhibit efflux pumps, biofilm formation, and quorum-sensing systems. The purpose of this study was to investigate whether baicalin can inhibit S. saprophyticus biofilm formation and the quorum-sensing system by inhibiting the MsrA efflux pump. First, the mechanism of baicalin inhibiting efflux was investigated by the ethidium bromide (EtBr) efflux assay, measurement of ATP content, and pyruvate kinase (PK) activities. These results revealed that baicalin significantly reduced the efflux of EtBr, the ATP content, and the activity of PK. Moreover, its role in biofilm formation and the agr system was studied by crystal violet staining, confocal laser scanning microscopy, scanning electron microscopy, and real-time polymerase chain reaction. These results showed that baicalin decreased biofilm formation, inhibited bacterial aggregation, and downregulated mRNA transcription levels of the quorum-sensing system regulators agrA, agrC, RNAIII, and sarA. Correlation analysis indicated that there was a strong positive correlation between the efflux pump and biofilm formation and the agr system. We demonstrate for the first time that baicalin inhibits biofilm formation and the agr quorum-sensing system by inhibiting the efflux pump in S. saprophyticus. Therefore, baicalin is a potential therapeutic agent for S. saprophyticus biofilm-associated infections.

RevDate: 2020-01-14

Dieltjens L, Appermans K, Lissens M, et al (2020)

Inhibiting bacterial cooperation is an evolutionarily robust anti-biofilm strategy.

Nature communications, 11(1):107.

Bacteria commonly form dense biofilms encased in extracellular polymeric substances (EPS). Biofilms are often extremely tolerant to antimicrobials but their reliance on shared EPS may also be a weakness as social evolution theory predicts that inhibiting shared traits can select against resistance. Here we show that EPS of Salmonella biofilms is a cooperative trait whose benefit is shared among cells, and that EPS inhibition reduces both cell attachment and antimicrobial tolerance. We then compare an EPS inhibitor to conventional antimicrobials in an evolutionary experiment. While resistance against conventional antimicrobials rapidly evolves, we see no evolution of resistance to EPS inhibition. We further show that a resistant strain is outcompeted by a susceptible strain under EPS inhibitor treatment, explaining why resistance does not evolve. Our work suggests that targeting cooperative traits is a viable solution to the problem of antimicrobial resistance.

RevDate: 2020-01-09

Eddenden A, Kitova EN, Klassen JS, et al (2020)

An inactive Dispersin B probe for monitoring PNAG production in biofilm formation.

ACS chemical biology [Epub ahead of print].

The bacterial exopolysaccharide poly-β-1,6-N-acetylglucosamine is a major extracellular matrix component in biofilms of both Gram-positive and Gram-negative organisms. We have leveraged the specificity of the biofilm-dispersing glycoside hydrolase Dispersin B (DspB) to generate a probe (Dispersin B PNAG probe, DiPP) for monitoring PNAG production and localization during biofilm formation. Mutation of the active site of Dispersin B gave DiPP which was an effective probe despite its low affinity for PNAG oligosaccharides, observed in fluorescence quenching and mass spectrometry binding experiments. Imaging of PNAG-dependent and -independent biofilms stained with a fluorescent-protein fusion of DiPP (GFP-DiPP) demonstrated the specificity of the probe for the structure of PNAG on both single-cell and biofilm levels. Through quantitative bacterial cell binding assays and confocal microscopy analysis using GFP-DiPP, discrete areas of local high concentrations of PNAG were detected on the surface of early log phase cells. These distinct areas were seen to grow, slough from cells and accumulate in interbacterial regions over the course of several cell divisions, showing the development of a PNAG-dependent biofilm. A potential helical distribution of staining was also noted, suggesting some degree of organization of PNAG production at the cell surface prior to cell aggregation. Together these experiments shed light on the early stages of PNAG dependent biofilm formation and demonstrate the value of a low-affinity-high-specificity probe for monitoring the production of bacterial exopolysaccharides.

RevDate: 2020-01-09

Araújo Lima AV, da Silva SM, do Nascimento Júnior JAA, et al (2020)

Occurrence and Diversity of Intra- and Interhospital Drug-Resistant and Biofilm-Forming Acinetobacter baumannii and Pseudomonas aeruginosa.

Microbial drug resistance (Larchmont, N.Y.) [Epub ahead of print].

Acinetobacter baumannii and Pseudomonas aeruginosa are the most relevant Gram-negative bacteria associated with hospital and opportunistic infections. This study aimed to evaluate the dynamics of drug-resistant A. baumannii and P. aeruginosa and biofilm formers from two public hospitals in northeastern Brazil. One hundred isolates (35 from A. baumannii and 65 from P. aeruginosa) were identified using the automated Vitek®2 Compact method (bioMérieux) and confirmed using the MALDI-TOF (MS) mass spectrometry technique. Molecular experiments were performed by polymerase chain reaction (PCR) to detect the frequency of blaKPC, blaIMP, blaVIM, and blaSHV genes. The biofilm formation potential was evaluated using crystal violet in Luria Bertani Miller and trypticase soy broth culture media under the following conditions: at standard concentration, one quarter (25%) of the standard concentration and supplemented with 1% glucose. In addition, the genetic diversity of the isolates was verified by the ERIC-PCR technique. Isolates presented distinct resistance profiles with a high level of beta-lactam resistance. The highest index of genes detected was blaKPC (60%), followed by blaSHV (39%), blaVIM (8%), and blaIMP (1%). All the isolates were sensitive to the polymyxins tested and formed biofilms at different intensities. Twelve clones of A. baumannii and eight of P. aeruginosa were identified, of which few were indicative of intra- and interhospital dissemination. This study reveals the dispersion dynamics of these isolates in the hospital environment. The results demonstrate the importance of monitoring programs to combat the spread of these pathogens.

RevDate: 2020-01-12

Samoilova Z, Tyulenev A, Muzyka N, et al (2019)

Tannic and gallic acids alter redox-parameters of the medium and modulate biofilm formation.

AIMS microbiology, 5(4):379-392.

Tannic (TA) and gallic (GA) acids are known to have both anti- and prooxidant properties however recently they have been described as potential anti-biofilm agents although their mechanisms of action on bacterial cells remain obscure. The aim of our research was to elucidate the role of prooxidant actions of these plant phenolic compounds in bactericidal effects and biofilm formation. In our experiments, both compounds demonstrated strong oxidative properties that altered activity of stress regulons and contributed to decrease of CFU and ability of cells to maintain membrane potential. Stimulation of biofilm formation was observed in all the strains with the exception of the strains deficient in flagella synthesis. Both compounds demonstrated bactericidal effect which was weakened in biofilms. TA efficiently killed bacteria in the bioflms of pgaA mutant which pointed out an important role of poly-beta-1,6-N-acetyl-D-glucosamine (PGA) polysaccharide in matrix formation. Similar effects of TA in recA mutant indicate involvement of SOS-response into reaction towards exposure with TA. Gallic acid-induced killing was more pronounced in the biofilms of csgA mutant revealing role of curli in protection against GA toxicity.

RevDate: 2020-01-08

Oanh NT, Duc HD, Ngoc DTH, et al (2020)

Biodegradation of propanil by Acinetobacter baumannii DT in a biofilm-batch reactor and effects of butachlor on the degradation process.

FEMS microbiology letters pii:5698327 [Epub ahead of print].

The herbicide, propanil, has been extensively applied in weed control, which causes serious environmental pollution. Acinetobacter baumannii DT isolated from soil and has been used to determine the degradation rates of propanil and 3,4-dichloroaniline by freely suspended and biofilm cells. The results showed that the bacterial isolate could utilize both compounds as sole carbon and nitrogen sources. Edwards's model could be fitted well to the degradation kinetics of propanil, with the maximum degradation of 0.027 ± 0.003 mM h-1. The investigation of the degradation pathway showed that A. baumannii DT transformed propanil to 3,4-dichloroaniline before being completely degraded via the ortho-cleavage pathway. In addition, A. baumannii DT showed high tolerance to butachlor, an herbicide usually mixed with propanil to enhance weed control. The presence of propanil and butachlor in the liquid media increased the cell surface hydrophobicity and biofilm formation. Moreover, the biofilm reactor showed increased degradation rates of propanil and butachlor and high tolerance of bacteria to these chemicals. The obtained results showed that A. baumannii DT has a high potential in the degradation of propanil.

RevDate: 2020-01-17

Prades L, Fabbri S, Dorado AD, et al (2020)

Computational and Experimental Investigation of Biofilm Disruption Dynamics Induced by High-Velocity Gas Jet Impingement.

mBio, 11(1):.

Experimental data showed that high-speed microsprays can effectively disrupt biofilms on their support substratum, producing a variety of dynamic reactions such as elongation, displacement, ripple formation, and fluidization. However, the mechanics underlying the impact of high-speed turbulent flows on biofilm structure is complex under such extreme conditions, since direct measurements of viscosity at these high shear rates are not possible using dynamic testing instruments. Here, we used computational fluid dynamics simulations to assess the complex fluid interactions of ripple patterning produced by high-speed turbulent air jets impacting perpendicular to the surface of Streptococcus mutans biofilms, a dental pathogen causing caries, captured by high-speed imaging. The numerical model involved a two-phase flow of air over a non-Newtonian biofilm, whose viscosity as a function of shear rate was estimated using the Herschel-Bulkley model. The simulation suggested that inertial, shear, and interfacial tension forces governed biofilm disruption by the air jet. Additionally, the high shear rates generated by the jet impacts coupled with shear-thinning biofilm property resulted in rapid liquefaction (within milliseconds) of the biofilm, followed by surface instability and traveling waves from the impact site. Our findings suggest that rapid shear thinning under very high shear flows causes the biofilm to behave like a fluid and elasticity can be neglected. A parametric sensitivity study confirmed that both applied force intensity (i.e., high jet nozzle air velocity) and biofilm properties (i.e., low viscosity and low air-biofilm surface tension and thickness) intensify biofilm disruption by generating large interfacial instabilities.IMPORTANCE Knowledge of mechanisms promoting disruption though mechanical forces is essential in optimizing biofilm control strategies which rely on fluid shear. Our results provide insight into how biofilm disruption dynamics is governed by applied forces and fluid properties, revealing a mechanism for ripple formation and fluid-biofilm mixing. These findings have important implications for the rational design of new biofilm cleaning strategies with fluid jets, such as determining optimal parameters (e.g., jet velocity and position) to remove the biofilm from a certain zone (e.g., in dental hygiene or debridement of surgical site infections) or using antimicrobial agents which could increase the interfacial area available for exchange, as well as causing internal mixing within the biofilm matrix, thus disrupting the localized microenvironment which is associated with antimicrobial tolerance. The developed model also has potential application in predicting drag and pressure drop caused by biofilms on bioreactor, pipeline, and ship hull surfaces.

RevDate: 2020-01-20

Islam J, Chilkoor G, Jawaharraj K, et al (2019)

Vitamin-C-enabled reduced graphene oxide chemistry for tuning biofilm phenotypes of methylotrophs on nickel electrodes in microbial fuel cells.

Bioresource technology, 300:122642 pii:S0960-8524(19)31871-1 [Epub ahead of print].

This study reports the use of multi-layered reduced graphene oxide (rGO) coating on porous nickel foam (NF) electrodes for enhancing biofilm growth of Rhodobacter Sphaeroides spp fed with methanol in microbial fuel cells (CH3OH-MFCs). Electrochemical methods were used to assess the methylotrophic activity on rGO/NF electrodes. The power density and current density offered by rGO/NF (1200 mW m-2 and 680 mA m-2) were 220-fold and 540-fold higher compared to bare NF (5.50 mW m-2 and 1.26 mA m-2), respectively. Electrochemical impedance spectroscopy results show that rGO/NF suppresses charge transfer resistance to CH3OH oxidation by 40-fold compared to the control. This improved performance is due to the ability of rGO coatings to decrease the wetting contact angle (improve the hydrophilicity) of NF from 1280 to 00. A preliminary cost analysis was carried out to assess the viability of rGO/NF electrodes via vitamin-C-enabled graphene oxide chemistry for CH3OH-MFCs applications.

RevDate: 2020-01-11

Omidi M, Firoozeh F, Saffari M, et al (2020)

Ability of biofilm production and molecular analysis of spa and ica genes among clinical isolates of methicillin-resistant Staphylococcus aureus.

BMC research notes, 13(1):19.

OBJECTIVE: This study aimed to evaluate the phenotypic and genotypic characterization of biofilm formation and spa and ica genes among clinical isolates of methicillin-resistant Staphylococcus aureus.

RESULT: This cross-sectional study was performed on 146 Staphylococcus aureus isolates from hospitalized patients in Isfahan Province Hospitals. MRSA isolates were confirmed using disk diffusion test with oxacillin disk and amplification of mecA gene by PCR assays. Ability of biofilm production was evaluated targeting the icaA and icaD genes. Of 146 Staphylococcus aureus isolates, 24 (16.4%) carried mecA genes and identified as MRSA strains. Strong ability of biofilm production was seen among 76.02% (111/146) S. aureus isolates and 87.5% (21/24) MRSA strains, respectively. Also, 75.0% (18/24) MRSA isolates carried icaA and icaD was not detected in these strains. Analysis of spa gene showed 70.83% (17/24) MRSA strains were spa positive. From which 14 and 3 strains identified with one band (150, 270, 300, 360, 400 bp) and two bands (150-300 bp), respectively. According to data obtained, the prevalence of MRSA isolates from Isfahan Province Hospitals is relatively high and a remarkable percentage of them show strong power in biofilm production. Also analysis of spa gene showed a fairly large diversity among MRSA strains.

RevDate: 2020-01-07

Chen G, Song W, X Ying (2020)

Horizontal Gene Transfer of Short-Chain Dehydrogenase Coding Genes Contribute to the Biofilm Formation and Pathogenicity on Mycobacterium grossiae sp. nov. PB739T (=DSM 104744T).

Mycobacterium grossiae sp. nov. of type strain PB739T is a Gram-positive acid-alcohol-fast rod-shaped bacterium, which was recently isolated from a 76-year-old male who suffered from a 1-year history of hemoptysis. This strain was described as novel species in Mycobacterium genus. In this study, its genome was completely sequenced by PacBio technology, analyzed, and compared with other selected complete genome sequences of Mycobacterium to elucidate the distinct pathogenic features of the strain. The genomic analysis revealed that the genome of PB739T consists of one circular DNA chromosome of 5,637,923 bp with a GC content of 70.48% and one plasmid of 43,679 bp with a GC content of 66.24%. The entire genome contains 5434 predicted coding genes, 48 tRNAs, and 6 rRNA genes. Genome and comparative genomics against M. grossiae SCH identified three tandem short-chain dehydrogenase (SDR) genes which only exist in PB739T. These three tandem SDR genes locate in a Genomic island which was identified by Island Viewer. These SDR genes were predicted to be horizontally transferred from a Streptomyces ancestor based on phylogeny. Analysis of the mutant ΔSDR confirmed the relationship between these tandem genes with biofilm and pathogenicity. This report will provide us with an extended understanding of M. grossiae at the genomic level and would be helpful for understanding the evolution of Mycobacterium genus.

RevDate: 2020-01-08

Shokeen B, Park J, Duong E, et al (2020)

Role of FAD-I in Fusobacterial Interspecies Interaction and Biofilm Formation.

Microorganisms, 8(1): pii:microorganisms8010070.

: RadD, a major adhesin of oral fusobacteria, is part of a four-gene operon encoding the small lipoprotein FAD-I and two currently uncharacterized small proteins encoded by the rapA and rapB genes. Previously, we described a role for FAD-I in the induction of human B-defensin 2 (hBD2) upon contact with oral epithelial cells. Here, we investigated potential roles for fad-I, rapA, and rapB in interspecies interaction and biofilm formation. Gene inactivation mutants were generated for each of these genes in the nucleatum and polymorphum subspecies of Fusobacteriumnucleatum and characterized for their adherence to partner species, biofilm formation, and operon transcription. Binding to Streptococcusgordonii was increased in all mutant strains with Δfad-I having the most significant effect. This increased adherence was directly proportional to elevated radD transcript levels and resulted in significantly different architecture and height of the biofilms formed by Δfad-I and S.gordonii compared to the wild-type parent. In conclusion, FAD-I is important for fusobacterial interspecies interaction as its lack leads to increased production of the RadD adhesin suggesting a role of FAD-I in its regulation. This regulatory effect does not require the presence of functional RadD.

RevDate: 2020-01-08

Pompilio A, Savini V, Fiscarelli E, et al (2020)

Clonal Diversity, Biofilm Formation, and Antimicrobial Resistance among Stenotrophomonas maltophilia Strains from Cystic Fibrosis and Non-Cystic Fibrosis Patients.

Antibiotics (Basel, Switzerland), 9(1): pii:antibiotics9010015.

The intrinsic antibiotic resistance of Stenotrophomonas maltophilia, along with its ability to form biofilm both on abiotic surfaces and host tissues, dramatically affects the efficacy of the antibiotic therapy. In this work, 85 S. maltophilia strains isolated in several hospital of central Italy and from several clinical settings were evaluated for their genetic relatedness (by pulsed-field gel electrophoresis, PFGE), biofilm formation (by microtiter plate assay), and planktonic antibiotic resistance (by Kirby-Bauer disk diffusion technique). The S. maltophilia population showed a high genetic heterogeneity: 64 different PFGE types were identified, equally distributed in cystic fibrosis (CF) and non-CF strains, and some consisted of multiple strains. Most of the strains (88.2%) were able to form biofilm, although non-CF strains were significantly more efficient than CF strains. CF strains produced lower biofilm amounts than non-CF strains, both those from respiratory tracts and blood. Non-CF PFGE types 3 and 27 consisted of strong-producers only. Cotrimoxazole and levofloxacin were the most effective antibiotics, being active respectively against 81.2% and 72.9% of strains. CF strains were significantly more resistant to piperacillin/tazobactam compared to non-CF strains (90% versus 53.3%), regardless of sample type. Among respiratory strains, cotrimoxazole was more active against non-CF than CF strains (susceptibility rates: 86.7% versus 75%). The multidrug resistant phenotype was significantly more prevalent in CF than non-CF strains (90% versus 66.7%). Overall, the multidrug-resistance level was negatively associated with efficiency in biofilm formation. Our results showed, for the first time, that in S. maltophilia both classical planktonic drug resistance and the ability of biofilm formation might favor its dissemination in the hospital setting. Biofilm formation might in fact act as a survival mechanism for susceptible bacteria, suggesting that clinical isolates should be routinely assayed for biofilm formation in diagnostic laboratories.

RevDate: 2020-01-08

Ishchuk OP, Sterner O, Ellervik U, et al (2019)

Simple Carbohydrate Derivatives Diminish the Formation of Biofilm of the Pathogenic Yeast Candida albicans.

Antibiotics (Basel, Switzerland), 9(1): pii:antibiotics9010010.

The opportunistic human fungal pathogen Candida albicans relies on cell morphological transitions to develop biofilm and invade the host. In the current study, we developed new regulatory molecules, which inhibit the morphological transition of C. albicans from yeast-form cells to cells forming hyphae. These compounds, benzyl α-l-fucopyranoside and benzyl β-d-xylopyranoside, inhibit the hyphae formation and adhesion of C. albicans to a polystyrene surface, resulting in a reduced biofilm formation. The addition of cAMP to cells treated with α-l-fucopyranoside restored the yeast-hyphae switch and the biofilm level to that of the untreated control. In the β-d-xylopyranoside treated cells, the biofilm level was only partially restored by the addition of cAMP, and these cells remained mainly as yeast-form cells.

RevDate: 2020-01-06

Sousa CA, Taborda MBB, Momesso GC, et al (2020)

Materials Sealing Preventing Biofilm Formation in Implant/Abutment Joints: Which Is the Most Effective? A Systematic Review and Meta-Analysis.

The Journal of oral implantology [Epub ahead of print].

The purpose of this systematic review was to evaluate the literature available for materials exhibiting the best efficacy in preventing biofilm formation in the interior of implants. We searched PubMed/MEDLINE, Scopus, and Cochrane databases. This review is registered with the PROSPERO database and followed the suitability of the PRISMA protocol. The initial search resulted in 326 articles from the databases. After they were read, eight articles remained and the inclusion and exclusion criteria were applied. Six of these eight articles were classified as in vitro and two were classified as in situ. The regions of the implants evaluated ranged from the interface of the pieces to the occlusal upper access of the abutment. The implant connections evaluated the Morse taper, external and internal connection. Meta-analysis of the quantitative data was performed at the significance level of 0.05. Cotton exhibited poor control of infiltration, even in combination with other materials. Isolated gutta-percha (GP) and polytetrafluoroethylene (PTFE) tape with composite resin (CR) or GP performed better as physical barriers. The best results for chemical barriers were observed by the application of 1% chlorhexidine gluconate (CG) gel, thymol varnish, and the deposition of Ag films onto the surface. The applied meta-analysis did not show a significant difference in comparison between the different types of implant connections (p>0.05). The application of CG and thymol varnish antimicrobials was effective in preventing biofilm formation and easy clinical execution; these could be used in combination with CR, GP, and PTFE.

RevDate: 2020-01-06

Ghorbanzadeh A, Bahador A, Sarraf P, et al (2020)

Ex Vivo Comparison of Antibacterial Efficacy of Conventional Chemomechanical Debridement Alone and in Combination with Light-Activated Disinfection and Laser Irradiation Against Enterococcus Faecalis Biofilm.

Photodiagnosis and photodynamic therapy pii:S1572-1000(19)30593-9 [Epub ahead of print].

BACKGROUND AND OBJECTIVES: Intracanal disinfection plays an important role in endodontic treatment success. Enterococcus faecalis (E. faecalis) is a resistant microorganism responsible for endodontic infections. We aimed to assess the bactericidal effects of three disinfection methods on E. faecalis biofilm.

MATERIALS AND METHODS: Fifty-five freshly extracted single-rooted human teeth were evaluated. A barbed broach was used to extract the pulp tissue. No further root canal preparation was performed. Specimens were sterilized with gamma radiation, and inoculated with E. faecalis suspension. They were then incubated for 4 days and 4 weeks. Biofilm formation was confirmed using a scanning electron microscope (SEM). The teeth were randomly assigned to three subgroups (n = 7) to assess the antimicrobial efficacy of the following three disinfection methods against immature (4-day) and mature (4-week) biofilms: the conventional chemomechanical debridement (CCMD), CCMD + light-activated disinfection (LAD; 810 nm, 0.3 W, 120 J/cm2) with indocyanine Green (EmunDo) as photosensitizer and CCMD + diode laser irradiation (810 nm, 2 W). The teeth were then longitudinally split into two halves and the colony count was reported as colony forming units (CFUs) to assess bacterial viability after each disinfection protocol.

RESULTS: None of the disinfection methods could completely remove the biofilm. CCMD + LAD caused the highest and CCMD + diode laser caused the lowest reduction in biofilm. Antibacterial efficacy was significantly lower against the mature (4-week) biofilm compared with immature (4-day) biofilm in all groups (P < 0.05).

CONCLUSION: All three disinfection methods were effective for partial elimination of E. faecalis biofilm. But CCMD + LAD was significantly more efficacious in decreasing both mature and immature biofilms.

RevDate: 2020-01-20

Ponce-Angulo DG, Bautista-Hernández LA, Calvillo-Medina RP, et al (2020)

Microscopic characterization of biofilm in mixed keratitis in a novel murine model.

Microbial pathogenesis, 140:103953 pii:S0882-4010(19)31161-1 [Epub ahead of print].

PURPOSE: To report the characterization and analysis of the biofilm formation in mixed keratitis induced by the coinfection of Staphylococcus aureus and Fusarium falciforme in a novel murine model.

METHODS: Clinical ocular microbial isolates and female BALB/c mice were used to develop the murine model. Immunosuppression was achieved with cyclophosphamide and methylprednisolone. A corneoscleral lesion was performed with a micro-pocket technique. Mice received an inoculum with a concentration of 1 × 105 conidia of F. falciforme and S. aureus with 1 × 105 UFC/ml. Mice were sacrificed at 72 h after induction of infection, the right eye was enucleated and preserved in 10% formaldehyde to perform the PAS staining. In addition, cuts were obtained for the labeling with the fluorophores propidium iodide and Calcofluor White, and other eye cuts were processed to transmission microscopy.

RESULTS: F. falciforme and S. aureus were able to developed mono and mixed biofilm in vitro. Keratitis of F. falciforme, S. aureus and mixed, were established at immunosuppressed mice. Clinical symptoms were observed at murine cornea. Histological analysis by special stains identified bacterial, fungal and mixed biofilm structures at epithelial and stromal level. Extracellular matrix was observed surrounded clusters of bacterial, fungi and mixed by fluorescence and transmission electronic microscopy.

CONCLUSION: This study provides direct evidence of the establishment and formation of mixed biofilm in vitro, as well as in vivo on the corneal surface of mice in an experimentally induced S. aureus and F. falciforme mixed keratitis infection.

RevDate: 2020-01-06

Kheiri F, Kermanshahi RK, MM Feizabadi (2020)

The Inhibitory Effects of Lactobacillus Supernatants and Their Metabolites on the Growth and Biofilm Formation of Klebsiella pneumoniae.

Infectious disorders drug targets pii:IDDT-EPUB-103494 [Epub ahead of print].

BACKGROUND: Klebsiella pneumoniae is a common cause of hospital acquired infections including urinary tract infection (UTI). Biofilm formation makes the K. pneumoniae infection more complicated and carrying extended spectrum beta-lactamases (ESBLs) genes limits antibiotic choices for treatment. Lactobacillus strains are known as natural protective barriers against UTIs.

OBJECTIVES: This is a small in-vitro study aimed to determine the effect of probiotic Lactobacillus strains and some types of their metabolites on the growth and biofilm of UTI isolated and reference strain of Klebsiella pneumoniae.

METHODS: The efficacy of Lactobacillus supernatants and antibiotics in prevention and elimination of K. pneumoniae biofilms was determined using a quantitative adherence assay. A rapid colorimetric microplate bioassay was applied for detection of survived bacterial cells after treatment with antibacterial agents. Biofilm phenotypes were studied by scanning electron microscopy (SEM).

RESULTS: The results showed that seven out of eight ESBL producing uropathogenic K. pneumoniae isolates in this study were able to produce biofilm. Lactobacillus supernatants at 1:1 to 1:16 dilutions, had more than 95% biofilm-inhibitory and biofilm-killing properties on strong biofilm producer isolate. Supra-MIC levels of antibiotics had much lower anti-biofilm effect than Lactobacillus supernatant and left considerable alive biofilm cells.

CONCLUSIONS: Although antibiotic resistance increases in biofilm forms of Klebsiella pneumoniae, Lactobacillus supernatants have strong antibiofilm efficacy even in concentrations lower than MIC. Biofilm formation decreases considerably in the presence of Lactobacillus supernatants. Hydrogen peroxide is an effective product against growth and biofilm formation of Klebsiella pneumoniae.

RevDate: 2020-01-06

Leyva-Díaz JC, Monteoliva-García A, Martín-Pascual J, et al (2019)

Moving bed biofilm reactor as an alternative wastewater treatment process for nutrient removal and recovery in the circular economy model.

Bioresource technology pii:S0960-8524(19)31861-9 [Epub ahead of print].

Over the last years, an increasing concern has emerged regarding the eco-friendly management of wastewater. Apart from the role of wastewater treatment plants (WWTPs) for wastewater and sewage sludge treatment, the increasing need of the recovery of the resources contained in wastewater, such as nutrients and water, should be highlighted. This would allow for transforming a wastewater treatment plant (WWTP) into a sustainable technological system. The objective of this review is to propose a moving bed biofilm reactor (MBBR) as a novel technology that contributes to the circularity of the wastewater treatment sector according to the principles of circular economy. In this regard, this paper aims to consider the MBBR process as the initial step for water reuse, and nutrient removal and recovery, within the circular economy model.

RevDate: 2020-01-06

Aper D, Frömbling J, Bağcıoğlu M, et al (2020)

Comparison of metabolic adaptation and biofilm formation of Actinobacillus pleuropneumoniae field isolates from the upper and lower respiratory tract of swine with respiratory disease.

Veterinary microbiology, 240:108532.

Most outbreaks of disease due to infection with Actinobacillus (A.) pleuropneumoniae are caused by pigs already pre-colonised in tonsillar tissue, where the pathogen is protected from exposure to antibiotic substances administered for treatment. As it has been shown recently under experimental conditions, A. pleuropneumoniae displays host tissue-specific metabolic adaptation. In this study, pairs of A. pleuropneumoniae field isolates were recovered from lung as well as from tonsillar and nasal tissue from 20 pigs suffering from acute clinical signs of pleuropneumonia and showing characteristic pathological lung alterations. Metabolic adaptation to the porcine lower and upper respiratory tract of 32 A. pleuropneumoniae serotype 2 field isolates was examined using Fourier transform infrared (FTIR) spectroscopy as a high resolution metabolic fingerprinting method. All strains showed metabolic adaptations to organ tissue reflected by hierarchical cluster analysis of FTIR spectra similar to those previously observed under experimental conditions. Notably, differences in antimicrobial resistance patterns and minimal inhibitory concentrations of isolates from different tissues in the same animal, but not in biofilm production capability in a microtiter plate assay were found. Overall, biofilm formation was observed for 71 % of the isolates, confirming that A. pleuropneumoniae field isolates are generally able to form biofilms, although rather in a serotype-specific than in an organ-specific manner. A. pleuropneumoniae serotype 6 isolates formed significantly more biofilm than the other serotypes. Furthermore, biofilm production was negatively correlated to the lung lesion scores and tonsillar isolates tended to be more susceptible to antimicrobial substances with high bioavailability than lung isolates.


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.

ESP Content

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.

ESP Help

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).


ESP now offers a much improved and expanded collection of timelines, designed to give the user choice over subject matter and dates.


Biographical information about many key scientists.

Selected Bibliographies

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

ESP Picks from Around the Web (updated 07 JUL 2018 )