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Tran, Hoai My, Hien Tran, Marsilea A. Booth, Kate E. Fox, Thi Hiep Nguyen, Nhiem Tran et Phong A. Tran. « Nanomaterials for Treating Bacterial Biofilms on Implantable Medical Devices ». Nanomaterials 10, no 11 (13 novembre 2020) : 2253. http://dx.doi.org/10.3390/nano10112253.
Texte intégralRésumé :
Bacterial biofilms are involved in most device-associated infections and remain a challenge for modern medicine. One major approach to addressing this problem is to prevent the formation of biofilms using novel antimicrobial materials, device surface modification or local drug delivery; however, successful preventive measures are still extremely limited. The other approach is concerned with treating biofilms that have already formed on the devices; this approach is the focus of our manuscript. Treating biofilms associated with medical devices has unique challenges due to the biofilm’s extracellular polymer substance (EPS) and the biofilm bacteria’s resistance to most conventional antimicrobial agents. The treatment is further complicated by the fact that the treatment must be suitable for applying on devices surrounded by host tissue in many cases. Nanomaterials have been extensively investigated for preventing biofilm formation on medical devices, yet their applications in treating bacterial biofilm remains to be further investigated due to the fact that treating the biofilm bacteria and destroying the EPS are much more challenging than preventing adhesion of planktonic bacteria or inhibiting their surface colonization. In this highly focused review, we examined only studies that demonstrated successful EPS destruction and biofilm bacteria killing and provided in-depth description of the nanomaterials and the biofilm eradication efficacy, followed by discussion of key issues in this topic and suggestion for future development.
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Kvist, Malin, Viktoria Hancock et Per Klemm. « Inactivation of Efflux Pumps Abolishes Bacterial Biofilm Formation ». Applied and Environmental Microbiology 74, no 23 (3 octobre 2008) : 7376–82. http://dx.doi.org/10.1128/aem.01310-08.
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ABSTRACT Bacterial biofilms cause numerous problems in health care and industry; notably, biofilms are associated with a large number of infections. Biofilm-dwelling bacteria are particularly resistant to antibiotics, making it hard to eradicate biofilm-associated infections. Bacteria rely on efflux pumps to get rid of toxic substances. We discovered that efflux pumps are highly active in bacterial biofilms, thus making efflux pumps attractive targets for antibiofilm measures. A number of efflux pump inhibitors (EPIs) are known. EPIs were shown to reduce biofilm formation, and in combination they could abolish biofilm formation completely. Also, EPIs were able to block the antibiotic tolerance of biofilms. The results of this feasibility study might pave the way for new treatments for biofilm-related infections and may be exploited for prevention of biofilms in general.
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Hänsch, Gertrud Maria. « Host Defence against Bacterial Biofilms : “Mission Impossible” ? » ISRN Immunology 2012 (5 novembre 2012) : 1–17. http://dx.doi.org/10.5402/2012/853123.
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Bacteria living as biofilms have been recognised as the ultimate cause of persistent and destructive inflammatory processes. Biofilm formation is a well-organised, genetically-driven process, which is well characterised for numerous bacteria species. In contrast, the host response to bacterial biofilms is less well analysed, and there is the general believe that bacteria in biofilms escape recognition or eradication by the immune defence. In this review the host response to bacterial biofilms is discussed with particular focus on the role of neutrophils because these phagocytic cells are the first to infiltrate areas of bacterial infection, and because neutrophils are equipped with a wide arsenal of bactericidal and toxic entities. I come to the conclusion that bacterial biofilms are not inherently protected against the attack by neutrophils, but that control of biofilm formation is possible depending on a timely and sufficient host response.
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Peng, Qi, Xiaohua Tang, Wanyang Dong, Ning Sun et Wenchang Yuan. « A Review of Biofilm Formation of Staphylococcus aureus and Its Regulation Mechanism ». Antibiotics 12, no 1 (22 décembre 2022) : 12. http://dx.doi.org/10.3390/antibiotics12010012.
Texte intégralRésumé :
Bacteria can form biofilms in natural and clinical environments on both biotic and abiotic surfaces. The bacterial aggregates embedded in biofilms are formed by their own produced extracellular matrix. Staphylococcus aureus (S. aureus) is one of the most common pathogens of biofilm infections. The formation of biofilm can protect bacteria from being attacked by the host immune system and antibiotics and thus bacteria can be persistent against external challenges. Therefore, clinical treatments for biofilm infections are currently encountering difficulty. To address this critical challenge, a new and effective treatment method needs to be developed. A comprehensive understanding of bacterial biofilm formation and regulation mechanisms may provide meaningful insights against antibiotic resistance due to bacterial biofilms. In this review, we discuss an overview of S. aureus biofilms including the formation process, structural and functional properties of biofilm matrix, and the mechanism regulating biofilm formation.
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Masi, Elisa, Marzena Ciszak, Luisa Santopolo, Arcangela Frascella, Luciana Giovannetti, Emmanuela Marchi, Carlo Viti et Stefano Mancuso. « Electrical spiking in bacterial biofilms ». Journal of The Royal Society Interface 12, no 102 (janvier 2015) : 20141036. http://dx.doi.org/10.1098/rsif.2014.1036.
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In nature, biofilms are the most common form of bacterial growth. In biofilms, bacteria display coordinated behaviour to perform specific functions. Here, we investigated electrical signalling as a possible driver in biofilm sociobiology. Using a multi-electrode array system that enables high spatio-temporal resolution, we studied the electrical activity in two biofilm-forming strains and one non-biofilm-forming strain. The action potential rates monitored during biofilm-forming bacterial growth exhibited a one-peak maximum with a long tail, corresponding to the highest biofilm development. This peak was not observed for the non-biofilm-forming strain, demonstrating that the intensity of the electrical activity was not linearly related to the bacterial density, but was instead correlated with biofilm formation. Results obtained indicate that the analysis of the spatio-temporal electrical activity of bacteria during biofilm formation can open a new frontier in the study of the emergence of collective microbial behaviour.
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Ferguson, Berrylin J., et Donna B. Stolz. « Demonstration of Biofilm in Human Bacterial Chronic Rhinosinusitis ». American Journal of Rhinology 19, no 5 (septembre 2005) : 452–57. http://dx.doi.org/10.1177/194589240501900506.
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Background Bacterial biofilms may explain why some patients with bacterial chronic rhinosinusitis (CRS) improve while on antibiotics but relapse after completion of the antibiotic. In the human host, biofilms exist as a community of bacteria surrounded by a glycocalyx that is adherent to a foreign body or a mucosal surface with impaired host defense. Biofilms generate planktonic, nonadherent bacterial forms that may metastasize infection and generate systemic illness. These planktonic bacteria are susceptible to antibiotics, unlike the adherent biofilm. Methods We reviewed four cases of CRS using transmission electron microscopy (TEM) to assay for typical colony architecture of biofilms. Bacterial communities surrounded by a glycocalyx of inert cellular membrane materials consistent with a biofilm were shown in two patients. Results In the two patients without biofilm, a nonbacterial etiology was discovered (allergic fungal sinusitis) in one and in the other there was scant anaerobic growth on culture and the Gram stain was negative. Culture of the material from the biofilm grew Pseudomonas aeruginosa in both patients. Pseudomonas from the biofilm showed a glycocalyx, not present in Pseudomonas cultured for 72 hours on culture media. Both patients’ symptoms with bacterial biofilms were refractory to culture-directed antibiotics, topical steroids, and nasal lavages. Surgery resulted in cure or significant improvement. Conclusion Biofilms are refractory to antibiotics and often only cured by mechanical debridement. We believe this is the first TEM documentation of bacterial biofilms in CRS in humans.
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Nesse, Live L., Ane Mohr Osland et Lene K. Vestby. « The Role of Biofilms in the Pathogenesis of Animal Bacterial Infections ». Microorganisms 11, no 3 (28 février 2023) : 608. http://dx.doi.org/10.3390/microorganisms11030608.
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Biofilms are bacterial aggregates embedded in a self-produced, protective matrix. The biofilm lifestyle offers resilience to external threats such as the immune system, antimicrobials, and other treatments. It is therefore not surprising that biofilms have been observed to be present in a number of bacterial infections. This review describes biofilm-associated bacterial infections in most body systems of husbandry animals, including fish, as well as in sport and companion animals. The biofilms have been observed in the auditory, cardiovascular, central nervous, digestive, integumentary, reproductive, respiratory, urinary, and visual system. A number of potential roles that biofilms can play in disease pathogenesis are also described. Biofilms can induce or regulate local inflammation. For some bacterial species, biofilms appear to facilitate intracellular invasion. Biofilms can also obstruct the healing process by acting as a physical barrier. The long-term protection of bacteria in biofilms can contribute to chronic subclinical infections, Furthermore, a biofilm already present may be used by other pathogens to avoid elimination by the immune system. This review shows the importance of acknowledging the role of biofilms in animal bacterial infections, as this influences both diagnostic procedures and treatment.
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Jacques, Mario, Virginia Aragon et Yannick D. N. Tremblay. « Biofilm formation in bacterial pathogens of veterinary importance ». Animal Health Research Reviews 11, no 2 (25 octobre 2010) : 97–121. http://dx.doi.org/10.1017/s1466252310000149.
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AbstractBacterial biofilms are structured communities of bacterial cells enclosed in a self-produced polymer matrix that is attached to a surface. Biofilms protect and allow bacteria to survive and thrive in hostile environments. Bacteria within biofilms can withstand host immune responses, and are much less susceptible to antibiotics and disinfectants when compared with their planktonic counterparts. The ability to form biofilms is now considered a universal attribute of micro-organisms. Diseases associated with biofilms require novel methods for their prevention, diagnosis and treatment; this is largely due to the properties of biofilms. Surprisingly, biofilm formation by bacterial pathogens of veterinary importance has received relatively little attention. Here, we review the current knowledge of bacterial biofilms as well as studies performed on animal pathogens.
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Noguchi, Nobuo, Yuichiro Noiri, Masahiro Narimatsu et Shigeyuki Ebisu. « Identification and Localization of Extraradicular Biofilm-Forming Bacteria Associated with Refractory Endodontic Pathogens ». Applied and Environmental Microbiology 71, no 12 (décembre 2005) : 8738–43. http://dx.doi.org/10.1128/aem.71.12.8738-8743.2005.
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ABSTRACT Bacterial biofilms have been found to develop on root surfaces outside the apical foramen and be associated with refractory periapical periodontitis. However, it is unknown which bacterial species form extraradicular biofilms. The present study aimed to investigate the identity and localization of bacteria in human extraradicular biofilms. Twenty extraradicular biofilms, used to identify bacteria using a PCR-based 16S rRNA gene assay, and seven root-tips, used to observe immunohistochemical localization of three selected bacterial species, were taken from 27 patients with refractory periapical periodontitis. Bacterial DNA was detected from 14 of the 20 samples, and 113 bacterial species were isolated. Fusobacterium nucleatum (14 of 14), Porphyromonas gingivalis (12 of 14), and Tannellera forsythensis (8 of 14) were frequently detected. Unidentified and uncultured bacterial DNA was also detected in 11 of the 14 samples in which DNA was detected. In the biofilms, P. gingivalis was immunohistochemically detected in all parts of the extraradicular biofilms. Positive reactions to anti-F. nucleatum and anti-T. forsythensis sera were found at specific portions of the biofilm. These findings suggested that P. gingivalis, T. forsythensis, and F. nucleatum were associated with extraradicular biofilm formation and refractory periapical periodontitis.
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Liu, Siyu, Hongyun Lu, Shengliang Zhang, Ying Shi et Qihe Chen. « Phages against Pathogenic Bacterial Biofilms and Biofilm-Based Infections : A Review ». Pharmaceutics 14, no 2 (16 février 2022) : 427. http://dx.doi.org/10.3390/pharmaceutics14020427.
Texte intégralRésumé :
Bacterial biofilms formed by pathogens are known to be hundreds of times more resistant to antimicrobial agents than planktonic cells, making it extremely difficult to cure biofilm-based infections despite the use of antibiotics, which poses a serious threat to human health. Therefore, there is an urgent need to develop promising alternative antimicrobial therapies to reduce the burden of drug-resistant bacterial infections caused by biofilms. As natural enemies of bacteria, bacteriophages (phages) have the advantages of high specificity, safety and non-toxicity, and possess great potential in the defense and removal of pathogenic bacterial biofilms, which are considered to be alternatives to treat bacterial diseases. This work mainly reviews the composition, structure and formation process of bacterial biofilms, briefly discusses the interaction between phages and biofilms, and summarizes several strategies based on phages and their derivatives against biofilms and drug-resistant bacterial infections caused by biofilms, serving the purpose of developing novel, safe and effective treatment methods against biofilm-based infections and promoting the application of phages in maintaining human health.
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Olapade, Ola A., et Laura G. Leff. « Influence of dissolved organic matter and inorganic nutrients on the biofilm bacterial community on artificial substrates in a northeastern Ohio, USA, stream ». Canadian Journal of Microbiology 52, no 6 (1 juin 2006) : 540–49. http://dx.doi.org/10.1139/w06-003.
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Stream bacteria may be influenced by the composition and availability of dissolved organic matter (DOM) and inorganic nutrients, but knowledge about how individual phylogenetic groups in biofilm are affected is still limited. In this study, the influence of DOM and inorganic nutrients on stream biofilm bacteria was examined. Biofilms were developed on artificial substrates (unglazed ceramic tiles) for 21 days in a northeastern Ohio (USA) stream for five consecutive seasons. Then, the developed biofilm assemblages were exposed, in the laboratory, to DOM (glucose, leaf leachate, and algal exudates) and inorganic nutrients (nitrate, phosphate, and nitrate and phosphate in combination) amendments for 6 days. Bacterial numbers in the biofilms were generally higher in response to the DOM treatments than to the inorganic nutrient treatments. There were also apparent seasonal variations in the response patterns of the individual bacterial taxa to the nutrient treatments; an indication that limiting resources to bacteria in stream biofilms may change over time. Overall, in contrast to the other treatments, bacterial abundance was generally highest in response to the low-molecular-weight DOM (i.e., glucose) treatment. These results further suggest that there are interactions among the different bacterial groups in biofilms that are impacted by the associated nutrient dynamics among seasons in stream ecosystems.Key words: biofilms, nutrients, DOM, bacteria, in situ hybridization.
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Akita, Hironaga, Yoshiki Shinto et Zen-ichiro Kimura. « Bacterial Community Analysis of Biofilm Formed on Metal Joint ». Applied Biosciences 1, no 2 (6 septembre 2022) : 221–28. http://dx.doi.org/10.3390/applbiosci1020014.
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Microbiologically influenced corrosion (MIC) is caused by biofilms formed on metal surfaces, and MIC of metal alloys on marine infrastructure leads to severe accidents and great economic losses. Although bacterial community analyses of the biofilms collected from corroded metal have been studied, the analyses of biofilms collected from uncorroded metal are rarely reported. In this study, a biofilm formed on an uncorroded metal joint attached to a metal dock mooring at Akitsu Port was used as a model for bacterial community analysis. The bacterial community was analyzed by high-throughput sequencing of the V3–V4 variable regions of the 16S rRNA gene. Bacterial species contained in the biofilms were identified at the genus level, and Alkanindiges bacteria were the dominant species, which have been not reported as the dominant species in previous research on MIC. The genome sequences of known Alkanindiges bacteria do not have conserved gene clusters required to cause metal corrosion, which suggests that Alkanindiges bacteria do not corrode metals but act on the formation of biofilms. Those findings indicated that the bacterial community may change significantly during the process from biofilm formation to the occurrence of metal corrosion.
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Cruz, Adriana, Manuel Condinho, Beatriz Carvalho, Cecília M. Arraiano, Vânia Pobre et Sandra N. Pinto. « The Two Weapons against Bacterial Biofilms : Detection and Treatment ». Antibiotics 10, no 12 (3 décembre 2021) : 1482. http://dx.doi.org/10.3390/antibiotics10121482.
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Bacterial biofilms are defined as complex aggregates of bacteria that grow attached to surfaces or are associated with interfaces. Bacteria within biofilms are embedded in a self-produced extracellular matrix made of polysaccharides, nucleic acids, and proteins. It is recognized that bacterial biofilms are responsible for the majority of microbial infections that occur in the human body, and that biofilm-related infections are extremely difficult to treat. This is related with the fact that microbial cells in biofilms exhibit increased resistance levels to antibiotics in comparison with planktonic (free-floating) cells. In the last years, the introduction into the market of novel compounds that can overcome the resistance to antimicrobial agents associated with biofilm infection has slowed down. If this situation is not altered, millions of lives are at risk, and this will also strongly affect the world economy. As such, research into the identification and eradication of biofilms is important for the future of human health. In this sense, this article provides an overview of techniques developed to detect and imaging biofilms as well as recent strategies that can be applied to treat biofilms during the several biofilm formation steps.
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Rocco, Christopher J., Lauren O. Bakaletz et Steven D. Goodman. « Targeting the HUβ Protein PreventsPorphyromonas gingivalisfrom Entering into Preexisting Biofilms ». Journal of Bacteriology 200, no 11 (5 février 2018) : e00790-17. http://dx.doi.org/10.1128/jb.00790-17.
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ABSTRACTThe oral cavity is home to a wide variety of bacterial species, both commensal, such as various streptococcal species, and pathogenic, such asPorphyromonas gingivalis, one of the main etiological agents of periodontal disease. Our understanding of how these bacteria ultimately cause disease is highly dependent upon understanding how they coexist and interact with one another in biofilm communities and the mechanisms by which biofilms are formed. Our research has demonstrated that the DNABII family of DNA-binding proteins are important components of the extracellular DNA (eDNA)-dependent matrix of bacterial biofilms and that sequestering these proteins via protein-specific antibodies results in the collapse of the biofilm structure and release of the resident bacteria. While the high degree of similarity among the DNABII family of proteins has allowed antibodies derived against specific DNABII proteins to disrupt biofilms formed by a wide range of bacterial pathogens, the DNABII proteins ofP. gingivalishave proven to be antigenically distinct, allowing us to determine if we can use anti-P. gingivalisHUβ antibodies to specifically target this species for removal from a mixed-species biofilm. Importantly, despite forming homotypic biofilmsin vitro,P. gingivalismust enter preexisting biofilmsin vivoin order to persist within the oral cavity. The data presented here indicate that antibodies derived against theP. gingivalisDNABII protein, HUβ, reduce by half the amount ofP. gingivalisorganisms entering into preexisting biofilm formed by four oral streptococcal species. These results support our efforts to develop methods for preventing and treating periodontal disease.IMPORTANCEPeriodontitis is one of the most prevalent chronic infections, affecting 40 to 50% of the population of the United States. The root cause of periodontitis is the presence of bacterial biofilms within the gingival space, withPorphyromonas gingivalisbeing strongly associated with the development of the disease. Periodontitis also increases the risk of secondary conditions and infections such as atherosclerosis and infective endocarditis caused by oral streptococci. To induce periodontitis,P. gingivalisneeds to incorporate into preformed biofilms, with oral streptococci being important binding partners. Our research demonstrates that targeting DNABII proteins with an antibody disperses oral streptococcus biofilm and preventsP. gingivalisentry into oral streptococcus biofilm. These results suggest potential therapeutic treatments for endocarditis caused by streptococci as well as periodontitis.
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Ancy Chacko, Deepti, et Neha Dhaded. « Biofilm : An emergent form of bacterial life-a review ». IP Indian Journal of Conservative and Endodontics 6, no 2 (15 juin 2021) : 92–96. http://dx.doi.org/10.18231/j.ijce.2021.021.
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Biofilm formation is a method for bacteria to adapt for its survival, to put it another way, it act as a shield and prevents bacterial eradication. Microbial biofilms are one of the major reasons for progession of periradicular pathology. The article aims to concise and stratify the literature about, various factors that leads to biofilm formation their adaptation mechanisms, biofilms role in progression of peri-radicular infections, models developed to create biofilms, observation techniques of endodontic biofilms, and the effects of root canal irrigants and medicaments as well as lasers on endodontic biofilms.
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Sabra, Sherifa. « Elimination Virulent-pathogenic-biofilm Bacteria Using Highland-wild Salvia officinalis Preserve Bacterial-infection-control ». Biotechnology and Bioprocessing 2, no 2 (2 février 2021) : 01–04. http://dx.doi.org/10.31579/2766-2314/021.
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This work for this title "Elimination Virulent-pathogenic-biofilm (VPB) Bacteria Using Highland-wild (HLW) Salvia officinalis (S. officinalis) Preserve Bacterial-infection-control (BIC)"; the aim was to prove the importance of HLW S. officinalis extracts have therapeutic herbal importance. Through its effected on the isolated VPB bacteria caused infection diseases that may preserve BIC for individuals, which proved the effectiveness of the HLW S. officinalis daily use or therapeutic use. S. officinalis specimens were collected during the flowering period from HLW, Taif, KSA. Essential oils (EOs) were equipped and biofilms preparation, then laboratory methods deputy for anti-biofilms formation activity and biofilms elimination activity, finally biofilms metabolic grades measurement. The bacterial metabolic grades of anti-biofilms formation activity showed the HLW S. officinalis EOs extracts eliminated VPB bacteria and effects were greater. Anywhere Staphylococcous aureus (S. aureus) and Streptococcus pyogenes (S. pyogenes) were eliminated until 60 hours. While Pseudomonas aeruginosa (PA) was eliminated at 72 hours. The bacterial metabolic grades of biofilms elimination activity found the HLW S. officinalis EOs extracts eliminated within 8 hours (S. aureus and S. pyogenes), PA was to 10 hours. Concluded the HLW S. officinalis EOs extracts had proven its ability to eliminate VPB bacteria, and from that, it proven on the type used with healthy characteristics to maintain health and BIC. Recommendation: That topic recommend using the appropriate HLW S. officinalis EOs extracts for individuals daily to maintain the general health. In cases of illness, person must ask the "Specialized Physician" to determine the healthy and curative amount to use.
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Al-Mailem, D. M., M. K. Kansour et S. S. Radwan. « Hydrocarbonoclastic biofilms based on sewage microorganisms and their application in hydrocarbon removal in liquid wastes ». Canadian Journal of Microbiology 60, no 7 (juillet 2014) : 477–86. http://dx.doi.org/10.1139/cjm-2014-0214.
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Attempts to establish hydrocarbonoclastic biofilms that could be applied in waste-hydrocarbon removal are still very rare. In this work, biofilms containing hydrocarbonoclastic bacteria were successfully established on glass slides by submerging them in oil-free and oil-containing sewage effluent for 1 month. Culture-dependent analysis of hydrocarbonoclastic bacterial communities in the biofilms revealed the occurrence of the genera Pseudomonas, Microvirga, Stenotrophomonas, Mycobacterium, Bosea, and Ancylobacter. Biofilms established in oil-containing effluent contained more hydrocarbonoclastic bacteria than those established in oil-free effluent, and both biofilms had dramatically different bacterial composition. Culture-independent analysis of the bacterial flora revealed a bacterial community structure totally different from that determined by the culture-dependent method. In microcosm experiments, these biofilms, when used as inocula, removed between 20% and 65% crude oil, n-hexadecane, and phenanthrene from the surrounding effluent in 2 weeks, depending on the biofilm type, the hydrocarbon identity, and the culture conditions. More of the hydrocarbons were removed by biofilms established in oil-containing effluent than by those established in oil-free effluent, and by cultures incubated in the light than by those incubated in the dark. Meanwhile, the bacterial numbers and diversities were enhanced in the biofilms that had been previously used in hydrocarbon bioremediation. These novel findings pave a new way for biofilm-based hydrocarbon bioremediation, both in sewage effluent and in other liquid wastes.
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Shalepo, Kira V., Tatiana G. Mihailenko et Alevtina M. Savicheva. « The role of bacterial biofilms in the development of chronic pathological processes in the vagina and endometrium ». Journal of obstetrics and women's diseases 65, no 4 (15 juin 2016) : 65–75. http://dx.doi.org/10.17816/jowd65465-75.
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Microbial biofilms are a problem in many areas of medicine. When the vaginal ecological system is disturbed, well-structured polymicrobial biofilm, covering the vaginal epithelium and consisting of anaerobic bacteria, is formed, which may lead to the development of recurrent bacterial vaginosis. During an ascending infection and the development of chronic endometritis, bacterial biofilms are detected in the endometrium. Biofilms formed by bacteria residing in the urogenital tract of woman, may result in dysfunctions of the reproductive system, in-vitro fertilization failures, complications of pregnancy, adverse pregnancy outcomes. In the paper, literature data regarding causes of of biofilm formation, methods of detection and treatment of biofilm infections are reviewed.
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Hong, Sung-Ha, Jean-Baptiste Gorce, Horst Punzmann, Nicolas Francois, Michael Shats et Hua Xia. « Surface waves control bacterial attachment and formation of biofilms in thin layers ». Science Advances 6, no 22 (mai 2020) : eaaz9386. http://dx.doi.org/10.1126/sciadv.aaz9386.
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Formation of bacterial biofilms on solid surfaces within a fluid starts when bacteria attach to the substrate. Understanding environmental factors affecting the attachment and the early stages of the biofilm development will help develop methods of controlling the biofilm growth. Here, we show that biofilm formation is strongly affected by the flows in thin layers of bacterial suspensions controlled by surface waves. Deterministic wave patterns promote the growth of patterned biofilms, while wave-driven turbulent motion discourages patterned attachment of bacteria. Strong biofilms form under the wave antinodes, while inactive bacteria and passive particles settle under nodal points. By controlling the wavelength, its amplitude, and horizontal mobility of the wave patterns, one can shape the biofilm and either enhance the growth or discourage the formation of the biofilm. The results suggest that the deterministic wave-driven transport channels, rather than hydrodynamic forces acting on microorganisms, determine the preferred location for the bacterial attachment.
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Kesel, Sara, Stefan Grumbein, Ina Gümperlein, Marwa Tallawi, Anna-Kristina Marel, Oliver Lieleg et Madeleine Opitz. « Direct Comparison of Physical Properties of Bacillus subtilis NCIB 3610 and B-1 Biofilms ». Applied and Environmental Microbiology 82, no 8 (12 février 2016) : 2424–32. http://dx.doi.org/10.1128/aem.03957-15.
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ABSTRACTMany bacteria form surface-attached communities known as biofilms. Due to the extreme resistance of these bacterial biofilms to antibiotics and mechanical stresses, biofilms are of growing interest not only in microbiology but also in medicine and industry. Previous studies have determined the extracellular polymeric substances present in the matrix of biofilms formed byBacillus subtilisNCIB 3610. However, studies on the physical properties of biofilms formed by this strain are just emerging. In particular, quantitative data on the contributions of biofilm matrix biopolymers to these physical properties are lacking. Here, we quantitatively investigated three physical properties ofB. subtilisNCIB 3610 biofilms: the surface roughness and stiffness and the bulk viscoelasticity of these biofilms. We show how specific biomolecules constituting the biofilm matrix formed by this strain contribute to those biofilm properties. In particular, we demonstrate that the surface roughness and surface elasticity of 1-day-old NCIB 3610 biofilms are strongly affected by the surface layer protein BslA. For a second strain,B. subtilisB-1, which forms biofilms containing mainly γ-polyglutamate, we found significantly different physical biofilm properties that are also differently affected by the commonly used antibacterial agent ethanol. We show that B-1 biofilms are protected from ethanol-induced changes in the biofilm's stiffness and that this protective effect can be transferred to NCIB 3610 biofilms by the sole addition of γ-polyglutamate to growing NCIB 3610 biofilms. Together, our results demonstrate the importance of specific biofilm matrix components for the distinct physical properties ofB. subtilisbiofilms.
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Luo, Yu, Daniel F. McAuley, Catherine R. Fulton, Joana Sá Pessoa, Ronan McMullan et Fionnuala T. Lundy. « Targeting Candida albicans in dual-species biofilms with antifungal treatment reduces Staphylococcus aureus and MRSA in vitro ». PLOS ONE 16, no 4 (8 avril 2021) : e0249547. http://dx.doi.org/10.1371/journal.pone.0249547.
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Polymicrobial biofilms consisting of fungi and bacteria are frequently formed on endotracheal tubes and may contribute to development of ventilator associated pneumonia (VAP) in critically ill patients. This study aimed to determine the role of early Candida albicans biofilms in supporting dual-species (dual-kingdom) biofilm formation with respiratory pathogens in vitro, and investigated the effect of targeted antifungal treatment on bacterial cells within the biofilms. Dual-species biofilm formation between C. albicans and three respiratory pathogens commonly associated with VAP (Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus) was studied using quantitative PCR. It was shown that early C. albicans biofilms enhanced the numbers of E. coli and S. aureus (including methicillin resistant S. aureus; MRSA) but not P. aeruginosa within dual-species biofilms. Transwell assays demonstrated that contact with C. albicans was required for the increased bacterial cell numbers observed. Total Internal Reflection Fluorescence microscopy showed that both wild type and hyphal-deficient C. albicans provided a scaffold for initial bacterial adhesion in dual species biofilms. qPCR results suggested that further maturation of the dual-species biofilm significantly increased bacterial cell numbers, except in the case of E.coli with hyphal-deficient C. albicans (Ca_gcn5Δ/Δ). A targeted preventative approach with liposomal amphotericin (AmBisome®) resulted in significantly decreased numbers of S. aureus in dual-species biofilms, as determined by propidium monoazide-modified qPCR. Similar results were observed when dual-species biofilms consisting of clinical isolates of C. albicans and MRSA were treated with liposomal amphotericin. However, reductions in E. coli numbers were not observed following liposomal amphotericin treatment. We conclude that early C. albicans biofilms have a key supporting role in dual-species biofilms by enhancing bacterial cell numbers during biofilm maturation. In the setting of increasing antibiotic resistance, an important and unexpected consequence of antifungal treatment of dual-species biofilms, is the additional benefit of decreased growth of multi-drug resistant bacteria such as MRSA, which could represent a novel future preventive strategy.
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Joshi, Abhayraj S., Priyanka Singh et Ivan Mijakovic. « Interactions of Gold and Silver Nanoparticles with Bacterial Biofilms : Molecular Interactions behind Inhibition and Resistance ». International Journal of Molecular Sciences 21, no 20 (16 octobre 2020) : 7658. http://dx.doi.org/10.3390/ijms21207658.
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Many bacteria have the capability to form a three-dimensional, strongly adherent network called ‘biofilm’. Biofilms provide adherence, resourcing nutrients and offer protection to bacterial cells. They are involved in pathogenesis, disease progression and resistance to almost all classical antibiotics. The need for new antimicrobial therapies has led to exploring applications of gold and silver nanoparticles against bacterial biofilms. These nanoparticles and their respective ions exert antimicrobial action by damaging the biofilm structure, biofilm components and hampering bacterial metabolism via various mechanisms. While exerting the antimicrobial activity, these nanoparticles approach the biofilm, penetrate it, migrate internally and interact with key components of biofilm such as polysaccharides, proteins, nucleic acids and lipids via electrostatic, hydrophobic, hydrogen-bonding, Van der Waals and ionic interactions. Few bacterial biofilms also show resistance to these nanoparticles through similar interactions. The nature of these interactions and overall antimicrobial effect depend on the physicochemical properties of biofilm and nanoparticles. Hence, study of these interactions and participating molecular players is of prime importance, with which one can modulate properties of nanoparticles to get maximal antibacterial effects against a wide spectrum of bacterial pathogens. This article provides a comprehensive review of research specifically directed to understand the molecular interactions of gold and silver nanoparticles with various bacterial biofilms.
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Malic, Sladjana, Katja E. Hill, Anthony Hayes, Steven L. Percival, David W. Thomas et David W. Williams. « Detection and identification of specific bacteria in wound biofilms using peptide nucleic acid fluorescent in situ hybridization (PNA FISH) ». Microbiology 155, no 8 (1 août 2009) : 2603–11. http://dx.doi.org/10.1099/mic.0.028712-0.
Texte intégralRésumé :
Biofilms provide a reservoir of potentially infectious micro-organisms that are resistant to antimicrobial agents, and their importance in the failure of medical devices and chronic inflammatory conditions is increasingly being recognized. Particular research interest exists in the association of biofilms with wound infection and non-healing, i.e. chronic wounds. In this study, fluorescent in situ hybridization (FISH) was used in combination with confocal laser scanning microscopy (CLSM) to detect and characterize the spatial distribution of biofilm-forming bacteria which predominate within human chronic skin wounds (Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus sp. and Micrococcus sp.). In vitro biofilms were prepared using a constant-depth film fermenter and a reconstituted human epidermis model. In vivo biofilms were also studied using biopsy samples from non-infected chronic venous leg ulcers. The specificity of peptide nucleic acid (PNA) probes for the target organisms was confirmed using mixed preparations of planktonic bacteria and multiplex PNA probing. Identification and location of individual bacterial species within multi-species biofilms demonstrated that P. aeruginosa was predominant. CLSM revealed clustering of individual species within mixed-species biofilms. FISH analysis of archive chronic wound biopsy sections showed bacterial presence and allowed bacterial load to be determined. The application of this standardized procedure makes available an assay for identification of single- or multi-species bacterial populations in tissue biopsies. The technique provides a reliable tool to study bacterial biofilm formation and offers an approach to assess targeted biofilm disruption strategies in vivo.
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Morris, Cindy E., Jean-Michel Monier et Marie-Agnès Jacques. « A Technique To Quantify the Population Size and Composition of the Biofilm Component in Communities of Bacteria in the Phyllosphere ». Applied and Environmental Microbiology 64, no 12 (1 décembre 1998) : 4789–95. http://dx.doi.org/10.1128/aem.64.12.4789-4795.1998.
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ABSTRACT The presence of microbial biofilms in the phyllosphere of terrestrial plants has recently been demonstrated, but few techniques to study biofilms associated with living plant tissues are available. Here we report a technique to estimate the proportion of the bacterial population on leaves that is assembled in biofilms and to quantitatively isolate bacteria from the biofilm and nonbiofilm (solitary) components of phyllosphere microbial communities. This technique is based on removal of bacteria from leaves by gentle washing, separation of biofilm and solitary bacteria by filtration, and disintegration of biofilms by ultrasonication. The filters used for this technique were evaluated for their nonspecific retention rates of solitary bacteria and for the efficiency of filtration for different concentrations of solitary bacteria in the presence of biofilms and other particles. The lethality and efficiency of disintegration of the sonication conditions used here were also evaluated. Isolation and quantification of bacteria by this technique is based on use of culture media. However, oligonucleotide probes, sera, or epifluorescent stains could also be used for direct characterization of the biofilm and solitary bacteria in the suspensions generated by this technique. Preliminary results from estimates of biofilm abundance in phyllosphere communities show that bacteria in biofilms constitute between about 10 and 40% of the total bacterial population on broad-leaf endive and parsley leaves.
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Alasil, Saad Musbah, Rahmat Omar, Salmah Ismail, Mohd Yasim Yusof, Ghulam N. Dhabaan et Mahmood Ameen Abdulla. « Evidence of Bacterial Biofilms among Infected and Hypertrophied Tonsils in Correlation with the Microbiology, Histopathology, and Clinical Symptoms of Tonsillar Diseases ». International Journal of Otolaryngology 2013 (2013) : 1–11. http://dx.doi.org/10.1155/2013/408238.
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Diseases of the tonsils are becoming more resistant to antibiotics due to the persistence of bacteria through the formation of biofilms. Therefore, understanding the microbiology and pathophysiology of such diseases represent an important step in the management of biofilm-related infections. We have isolated the microorganisms, evaluated their antimicrobial susceptibility, and detected the presence of bacterial biofilms in tonsillar specimens in correlation with the clinical manifestations of tonsillar diseases. Therefore, a total of 140 palatine tonsils were collected from 70 patients undergoing tonsillectomy at University Malaya Medical Centre. The most recovered isolate wasStaphylococcus aureus(39.65%) followed byHaemophilus influenzae(18.53%). There was high susceptibility against all selected antibiotics except for cotrimoxazole. Bacterial biofilms were detected in 60% of patients and a significant percentage of patients demonstrated infection manifestation rather than obstruction. In addition, an association between clinical symptoms like snore, apnea, nasal obstruction, and tonsillar hypertrophy was found to be related to the microbiology of tonsils particularly to the presence of biofilms. In conclusion, evidence of biofilms in tonsils in correlation with the demonstrated clinical symptoms explains the recalcitrant nature of tonsillar diseases and highlights the importance of biofilm’s early detection and prevention towards better therapeutic management of biofilm-related infections.
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Makabenta, Jessa Marie V., Jungmi Park, Cheng-Hsuan Li, Aritra Nath Chattopadhyay, Ahmed Nabawy, Ryan F. Landis, Akash Gupta, Suzannah Schmidt-Malan, Robin Patel et Vincent M. Rotello. « Polymeric Nanoparticles Active against Dual-Species Bacterial Biofilms ». Molecules 26, no 16 (16 août 2021) : 4958. http://dx.doi.org/10.3390/molecules26164958.
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Biofilm infections are a global public health threat, necessitating new treatment strategies. Biofilm formation also contributes to the development and spread of multidrug-resistant (MDR) bacterial strains. Biofilm-associated chronic infections typically involve colonization by more than one bacterial species. The co-existence of multiple species of bacteria in biofilms exacerbates therapeutic challenges and can render traditional antibiotics ineffective. Polymeric nanoparticles offer alternative antimicrobial approaches to antibiotics, owing to their tunable physico-chemical properties. Here, we report the efficacy of poly(oxanorborneneimide) (PONI)-based antimicrobial polymeric nanoparticles (PNPs) against multi-species bacterial biofilms. PNPs showed good dual-species biofilm penetration profiles as confirmed by confocal laser scanning microscopy. Broad-spectrum antimicrobial activity was observed, with reduction in both bacterial viability and overall biofilm mass. Further, PNPs displayed minimal fibroblast toxicity and high antimicrobial activity in an in vitro co-culture model comprising fibroblast cells and dual-species biofilms of Escherichia coli and Pseudomonas aeruginosa. This study highlights a potential clinical application of the presented polymeric platform.
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Wang, Longfei, Yutao Wang, Yi Li, Wenlong Zhang, Huanjun Zhang, Lihua Niu et Nuzahat Habibul. « Benthic Biofilm Bacterial Communities and Their Linkage with Water-Soluble Organic Matter in Effluent Receivers ». International Journal of Environmental Research and Public Health 19, no 4 (10 février 2022) : 1994. http://dx.doi.org/10.3390/ijerph19041994.
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Benthic biofilms are pioneering microbial aggregates responding to effluent discharge from wastewater treatment plants (WWTPs). However, knowledge of the characteristics and linkage of bacterial communities and water-soluble organic matter (WSOM) of benthic biofilms in effluent-receiving rivers remains unknown. Here, we investigated the quality of WSOM and the evolution of bacterial communities in benthic biofilm to evaluate the ecological impacts of effluent discharge on a representative receiving water. Tryptophan-like proteins showed an increased proportion in biofilms collected from the discharge area and downstream from the WWTP, especially in summer. Biofilm WSOM showed weak humic character and strong autochthonous components, and species turnover was proven to be the main factor governing biofilm bacteria community diversity patterns. The bacterial community alpha diversity, interspecies interaction, biological index, and humification index were signally altered in the biofilms from the discharge area, while the values were more similar in biofilms collected upstream and downstream from the WWTP, indicating that both biofilm bacterial communities and WSOM characters have resilience capacities. Although effluent discharge simplified the network pattern of the biofilm bacterial community, its metabolic functional abundance was basically stable. The functional abundance of carbohydrate metabolism and amino acid metabolism in the discharge area increased, and the key modules in the non-random co-occurrence network also verified the important ecological role of carbon metabolism in the effluent-receiving river. The study sheds light on how benthic biofilms respond to effluent discharge from both ecological and material points of view, providing new insights on the feasibility of utilizing benthic biofilms as robust indicators reflecting river ecological health.
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Loke, Mun Fai, Indresh Yadav, Teck Kwang Lim, Johan R. C. van der Maarel, Lok-To Sham et Vincent T. Chow. « SARS-CoV-2 Spike Protein and Mouse Coronavirus Inhibit Biofilm Formation by Streptococcus pneumoniae and Staphylococcus aureus ». International Journal of Molecular Sciences 23, no 6 (18 mars 2022) : 3291. http://dx.doi.org/10.3390/ijms23063291.
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The presence of co-infections or superinfections with bacterial pathogens in COVID-19 patients is associated with poor outcomes, including increased morbidity and mortality. We hypothesized that SARS-CoV-2 and its components interact with the biofilms generated by commensal bacteria, which may contribute to co-infections. This study employed crystal violet staining and particle-tracking microrheology to characterize the formation of biofilms by Streptococcus pneumoniae and Staphylococcus aureus that commonly cause secondary bacterial pneumonia. Microrheology analyses suggested that these biofilms were inhomogeneous soft solids, consistent with their dynamic characteristics. Biofilm formation by both bacteria was significantly inhibited by co-incubation with recombinant SARS-CoV-2 spike S1 subunit and both S1 + S2 subunits, but not with S2 extracellular domain nor nucleocapsid protein. Addition of spike S1 and S2 antibodies to spike protein could partially restore bacterial biofilm production. Furthermore, biofilm formation in vitro was also compromised by live murine hepatitis virus, a related beta-coronavirus. Supporting data from LC-MS-based proteomics of spike–biofilm interactions revealed differential expression of proteins involved in quorum sensing and biofilm maturation, such as the AI-2E family transporter and LuxS, a key enzyme for AI-2 biosynthesis. Our findings suggest that these opportunistic pathogens may egress from biofilms to resume a more virulent planktonic lifestyle during coronavirus infections. The dispersion of pathogens from biofilms may culminate in potentially severe secondary infections with poor prognosis. Further detailed investigations are warranted to establish bacterial biofilms as risk factors for secondary pneumonia in COVID-19 patients.
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Hussein Neamah, Bent Alhuda. « Bacterial Biofilm And Role In The Pathogenesis Of Disease ». Medical Science Journal for Advance Research 3, no 4 (23 décembre 2022) : 179–83. http://dx.doi.org/10.46966/msjar.v3i4.82.
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Background: Bacterial biofilms may play a role in pathogenesis which has led to increased focus on identifying diseases that may be associated with biofilms. Chronic biofilm infections are usually chronic in nature, as the bacteria that live in biofilms can be resilient to both the immune system and antibiotics and other treatments. Current knowledge of how biofilms contribute to disease pathogenesis suggests a number of different mechanisms. This extends from biofilms being merely a reservoir of pathogenic bacteria, to playing a more active role, for example, by contributing to inflammation. This knowledge is important for developing effective treatment strategies for such infections.
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Pletzer, Daniel, et Robert E. W. Hancock. « Antibiofilm Peptides : Potential as Broad-Spectrum Agents ». Journal of Bacteriology 198, no 19 (11 avril 2016) : 2572–78. http://dx.doi.org/10.1128/jb.00017-16.
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The treatment of bacterial diseases is facing twin threats, with increasing bacterial antibiotic resistance and relatively few novel compounds or strategies under development or entering the clinic. Bacteria frequently grow on surfaces as biofilm communities encased in a polymeric matrix. The biofilm mode of growth is associated with 65 to 80% of all clinical infections. It causes broad adaptive changes; biofilm bacteria are especially (10- to 1,000-fold) resistant to conventional antibiotics and to date no antimicrobials have been developed specifically to treat biofilms. Small synthetic peptides with broad-spectrum antibiofilm activity represent a novel approach to treat biofilm-related infections. Recent developments have provided evidence that these peptides can inhibit even developed biofilms, kill multiple bacterial species in biofilms (including the ESKAPE [Enterococcus faecium,Staphylococcus aureus,Klebsiella pneumoniae,Acinetobacter baumannii,Pseudomonas aeruginosa, andEnterobacterspecies] pathogens), show strong synergy with several antibiotics, and act by targeting a universal stress response in bacteria. Thus, these peptides represent a promising alternative treatment to conventional antibiotics and work effectively in animal models of biofilm-associated infections.
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Yasir, Muhammad, Mark Willcox et Debarun Dutta. « Action of Antimicrobial Peptides against Bacterial Biofilms ». Materials 11, no 12 (5 décembre 2018) : 2468. http://dx.doi.org/10.3390/ma11122468.
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Microbes are known to colonize surfaces and form biofilms. These biofilms are communities of microbes encased in a self-produced matrix that often contains polysaccharides, DNA and proteins. Antimicrobial peptides (AMPs) have been used to control the formation and to eradicate mature biofilms. Naturally occurring or synthetic antimicrobial peptides have been shown to prevent microbial colonization of surfaces, to kill bacteria in biofilms and to disrupt the biofilm structure. This review systemically analyzed published data since 1970 to summarize the possible anti-biofilm mechanisms of AMPs. One hundred and sixty-two published reports were initially selected for this review following searches using the criteria ‘antimicrobial peptide’ OR ‘peptide’ AND ‘mechanism of action’ AND ‘biofilm’ OR ‘antibiofilm’ in the databases PubMed; Scopus; Web of Science; MEDLINE; and Cochrane Library. Studies that investigated anti-biofilm activities without describing the possible mechanisms were removed from the analysis. A total of 17 original reports were included which have articulated the mechanism of antimicrobial action of AMPs against biofilms. The major anti-biofilm mechanisms of antimicrobial peptides are: (1) disruption or degradation of the membrane potential of biofilm embedded cells; (2) interruption of bacterial cell signaling systems; (3) degradation of the polysaccharide and biofilm matrix; (4) inhibition of the alarmone system to avoid the bacterial stringent response; (5) downregulation of genes responsible for biofilm formation and transportation of binding proteins.
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Robika, Robika, Rahmad Lingga et Budi Afriyansyah. « Identification of Biofilm-Producing Bacteria From Nangka Island Marine Water in District of Bangka Tengah ». JURNAL PEMBELAJARAN DAN BIOLOGI NUKLEUS 8, no 1 (13 mars 2022) : 179–91. http://dx.doi.org/10.36987/jpbn.v8i1.2492.
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Bacterial community is an important element of an ecosystem both on land and in water. In aquatic ecosystems, bacteria that have the ability to produce biofilms have the advantage of being able to easily attach on a substrate. The main function of biofilm is assisting nutrition absorption from water and facilitating bacteria surviveness from unfavorable environmental conditions. This research was conducted to isolate and identify and test the potential of bacteria to form biofilms in vitro. The methodological steps included measuring the physical-chemical parameters of the waters; isolation by pour plating method; characterization and identification based on morphological, biochemical and Gram staining; as well as testing the activity of biofilm formation by reading technique using microplate reader. The highest bacterial abundance was found at Station 3 (muddy substrate) which was 3.3x106 cfu/ml. Bacterial isolates that had the highest ability to form biofilms in vitro were Bb3, Bb4 and Bb1 isolates with values of 0.3315, 0.2370) and 0.2131, respectively. Bacteria that have the potential to form biofilms from various substrates in the waters of Nangka Island belong to Alcaligenes and Meniscus genera. From the results of the study, it can be concluded that bacteria from rocky substrates have the ability to produce biofilms better than isolates from other substrates.
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Harding, Michael, Patricia Nadworny, Brenton Buziak, Amin Omar, Greg Daniels et Jie Feng. « Improved Methods for Treatment of Phytopathogenic Biofilms : Metallic Compounds as Anti-Bacterial Coatings and Fungicide Tank-Mix Partners ». Molecules 24, no 12 (22 juin 2019) : 2312. http://dx.doi.org/10.3390/molecules24122312.
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Fungi and bacteria cause disease issues in cultivated plants world-wide. In most cases, the fungi and bacteria colonize plant tissues as biofilms, which can be very challenging to destroy or eradicate. In this experiment, we employed a novel (biofilm) approach to crop disease management by evaluating the efficacies of six fungicides, and four silver-based compounds, versus biofilms formed by fungi and bacteria, respectively. The aim was to identify combinations of fungicides and metallic cations that showed potential to improve the control of white mold (WM), caused by the ascomycete fungus Sclerotinia sclerotiorum, and to evaluate novel high valency silver compounds as seed coatings to prevent biofilm formation of four bacterial blight pathogens on dry bean seeds. Our results confirmed that mature fungal biofilms were recalcitrant to inactivation by fungicides. When metallic cations were added to the fungicides, their efficacies were improved. Some improvements were statistically significant, with one combination (fluazinam + Cu2+) showing a synergistic effect. Additionally, coatings with silver compounds could reduce bacterial blight biofilms on dry bean seeds and oxysilver nitrate was the most potent inhibitor of bacterial blight.
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Feier, Andrei-Marian, Andrei-Constantin Ioanovici, Radu-Cristian Ionescu, Tamas Toth et Octav-Marius Russu. « Biofilm Inhibition : Compounds with Antibacterial Effects ». Journal of Interdisciplinary Medicine 3, no 4 (1 décembre 2018) : 234–38. http://dx.doi.org/10.2478/jim-2018-0042.
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Abstract Biofilms can form on living or inert surfaces and prevail in natural, industrial, and hospital environments. They are made of bacteria organized in a coordinated functional community. Biofilms do not respond to antibiotic treatment due to multiple mechanisms of tolerance and resistance. If bacteria are coordinated in a biofilm form, they are significantly less susceptible to antibiotics, thus making the therapeutic approach difficult. The possibility of using drugs aimed at inhibiting the formation of biofilms in combination with current antibiotics is a therapeutic approach with a major potential for this type of persistent bacterial infection. This bibliographic study aims to present the main compounds that act by inhibiting or destroying the bacterial biofilm.
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Crivello, G., L. Fracchia, G. Ciardelli, M. Boffito et C. Mattu. « In Vitro Models of Bacterial Biofilms : Innovative Tools to Improve Understanding and Treatment of Infections ». Nanomaterials 13, no 5 (27 février 2023) : 904. http://dx.doi.org/10.3390/nano13050904.
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Bacterial infections are a growing concern to the health care systems. Bacteria in the human body are often found embedded in a dense 3D structure, the biofilm, which makes their eradication even more challenging. Indeed, bacteria in biofilm are protected from external hazards and are more prone to develop antibiotic resistance. Moreover, biofilms are highly heterogeneous, with properties dependent on the bacteria species, the anatomic localization, and the nutrient/flow conditions. Therefore, antibiotic screening and testing would strongly benefit from reliable in vitro models of bacterial biofilms. This review article summarizes the main features of biofilms, with particular focus on parameters affecting biofilm composition and mechanical properties. Moreover, a thorough overview of the in vitro biofilm models recently developed is presented, focusing on both traditional and advanced approaches. Static, dynamic, and microcosm models are described, and their main features, advantages, and disadvantages are compared and discussed.
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Peyyala, R., S. Kirakodu, K. F. Novak et J. L. Ebersole. « Epithelial Interleukin-8 Responses to Oral Bacterial Biofilms ». Clinical and Vaccine Immunology 18, no 10 (10 août 2011) : 1770–72. http://dx.doi.org/10.1128/cvi.05162-11.
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ABSTRACTAnin vitromodel of bacterial biofilms on rigid gas-permeable contact lenses (RGPLs) was developed to challenge oral epithelial cells. This novel model provided seminal data on oral biofilm-host cell interactions, and with selected bacteria, the biofilms were more effective than their planktonic counterparts at stimulating host cell responses.
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Liu, Ruyin, Zhisheng Yu, Hongxun Zhang, Min Yang, Baoyou Shi et Xinchun Liu. « Diversity of bacteria and mycobacteria in biofilms of two urban drinking water distribution systems ». Canadian Journal of Microbiology 58, no 3 (mars 2012) : 261–70. http://dx.doi.org/10.1139/w11-129.
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In this study, to give insight into the bacterial diversity of biofilms from full-scale drinking water distribution systems (DWDSs), the bacterial community compositions of biofilms from two urban DWDSs (Guangzhou and Beijing, China) were determined using a 16S rRNA gene library technique. Meanwhile, the occurrence and diversity of mycobacteria were also analyzed by a Mycobacterium -specific hsp gene assay. The biofilms from the full-scale DWDSs have complex bacterial populations. Proteobacteria was the common and predominant group in all biofilm samples, in agreement with previous reports. The community structures of bacteria at the three sites in Guangzhou DWDS were significantly different, despite the similar physicochemical properties of portable water. Some abundant and peculiar bacterial phylotypes were noteworthy, including Methylophilus , Massilia , and Planomicrobium , members of which are rarely found in DWDSs and their roles in DWDS biofilms are still unclear. The diversity of Mycobacterium species in biofilm samples was rather low. Mycobacterium arupense and Mycobacterium gordonae were the primary Mycobacterium species in Guangzhou and Beijing biofilms, respectively, indicating that M. arupense may be more resistant to chloride than M. gordonae.
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Sjollema, Jelmer, Minie Rustema-Abbing, Henny C. van der Mei et Henk J. Busscher. « Generalized Relationship between Numbers of Bacteria and Their Viability in Biofilms ». Applied and Environmental Microbiology 77, no 14 (27 mai 2011) : 5027–29. http://dx.doi.org/10.1128/aem.00178-11.
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ABSTRACTBacterial biofilms are confined communities that are encapsulated in protective layers of extracellular polymeric substances. Microscopic evaluation of biofilms of diverse bacterial strains on various substrata reveals that, in general, the percentage of viable bacteria decreases with the total number of bacteria in a biofilm.
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Guenther, Frank, Petra Stroh, Christof Wagner, Ursula Obst et Gertrud Maria Hänsch. « Phagocytosis of Staphylococci Biofilms by Polymorphonuclear Neutrophils : S. aureus and S. epidermidis Differ with Regard to Their Susceptibility Towards the Host Defense ». International Journal of Artificial Organs 32, no 9 (septembre 2009) : 565–73. http://dx.doi.org/10.1177/039139880903200905.
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Bacteria organized in biofilms are a common cause of relapsing or persistent infections. In patients receiving orthopedic implants, such as endoprostheses or osteosynthesis materials, Staphylococcus aureus and S. epidermidis are prevalent and it is widely assumed that bacteria in biofilms are not only relatively resistant towards antibiotics and biocides, but also towards host defense mechanisms. In that context, we addressed the question how polymorphonuclear neutrophils (PMN), the “first line defense” against bacterial infection, interact with biofilms generated in vitro. By time-lapse video microscopy, we observed migration of PMN towards the biofilms. In the case of S. aureus, the PMN moved across the biofilm and took up bacteria as they moved along. On S. epidermidis, in contrast, the PMN were rather immobile, and phagocytosis was limited to bacteria in the immediate vicinity. By labeling the bacteria within the biofilm with 3H-thymidine we found that S. aureus biofilms were more sensitive towards the PMN attack than S. epidermidis. Following phagocytosis of either bacteria strain, the PMN underwent apoptosis, in line with the dogma, that phagocytosis induces programmed cell-death in order to prevent spilling of the bactericidal and cytotoxic entities. In conclusion, biofilms are not inherently protected against the attack by phagocytic cells; their sensitivity, however, varies among bacterial strains, presumably due to properties of the extracellular biofilm matrix affecting the motility of PMN on the film.
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Schlafer, Sebastian, Rikke L. Meyer, Irene Dige et Viduthalai R. Regina. « Extracellular DNA Contributes to Dental Biofilm Stability ». Caries Research 51, no 4 (2017) : 436–42. http://dx.doi.org/10.1159/000477447.
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Extracellular DNA (eDNA) is a major matrix component of many bacterial biofilms. While the presence of eDNA and its role in biofilm stability have been demonstrated for several laboratory biofilms of oral bacteria, there is no data available on the presence and function of eDNA in in vivo grown dental biofilms. This study aimed to determine whether eDNA was part of the matrix in biofilms grown in situ in the absence of sucrose and whether treatment with DNase dispersed biofilms grown for 2.5, 5, 7.5, 16.5, or 24 h. Three hundred biofilms from 10 study participants were collected and treated with either DNase or heat-inactivated DNase for 1 h. The bacterial biovolume was determined with digital image analysis. Staining with TOTO®-1 allowed visualization of eDNA both on bacterial cell surfaces and, with a cloud-like appearance, in the intercellular space. DNase treatment strongly reduced the amount of biofilm in very early stages of growth (up to 7.5 h), but the treatment effect decreased with increasing biofilm age. This study proves the involvement of eDNA in dental biofilm formation and its importance for biofilm stability in the earliest stages. Further research is required to uncover the interplay of eDNA and other matrix components and to explore the therapeutic potential of DNase treatment for biofilm control.
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Karatan, Ece, et Paula Watnick. « Signals, Regulatory Networks, and Materials That Build and Break Bacterial Biofilms ». Microbiology and Molecular Biology Reviews 73, no 2 (juin 2009) : 310–47. http://dx.doi.org/10.1128/mmbr.00041-08.
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SUMMARY Biofilms are communities of microorganisms that live attached to surfaces. Biofilm formation has received much attention in the last decade, as it has become clear that virtually all types of bacteria can form biofilms and that this may be the preferred mode of bacterial existence in nature. Our current understanding of biofilm formation is based on numerous studies of myriad bacterial species. Here, we review a portion of this large body of work including the environmental signals and signaling pathways that regulate biofilm formation, the components of the biofilm matrix, and the mechanisms and regulation of biofilm dispersal.
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Vuoriranta, P., M. Männistö et H. Soranummi. « Occurrence of Sphingomonas sp. bacteria in cold climate drinking water supply system biofilms ». Water Supply 3, no 1-2 (1 mars 2003) : 227–32. http://dx.doi.org/10.2166/ws.2003.0108.
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Members of the bacterial genus Sphingomonas (recently split into four genera), belonging to α-4-subclass of Proteobacteria, were isolated and characterised from water distribution network biofilms. Water temperature in the studied network, serving 200,000 people, is less than 5°C for about five months every winter. Sphingomonads, characterised using fluorescent oligonucleotide probes and fatty acid composition analysis (FAME), were a major group of bacteria among the distribution network biofilm isolates. Intact biofilms, grown on steel slides in a biofilm reactor fed with tap water, were detected in situ using fluorescence labelled oligonucleotide probes (FISH). Hybridisation with probes targeted on α-proteobacteria and sphingomonads was detected, but FISH on intact biofilms suffered from non-specific hybridisation and intensive autofluorescence, possibly due to extracellular material around the bacterial cells attached to biofilm. These preliminary results indicate that bacteria present in the distribution network biofilms in this study phylogenetically differ from those detected in more temperate regions.
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Uruén, Cristina, Gema Chopo-Escuin, Jan Tommassen, Raúl C. Mainar-Jaime et Jesús Arenas. « Biofilms as Promoters of Bacterial Antibiotic Resistance and Tolerance ». Antibiotics 10, no 1 (23 décembre 2020) : 3. http://dx.doi.org/10.3390/antibiotics10010003.
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Multidrug resistant bacteria are a global threat for human and animal health. However, they are only part of the problem of antibiotic failure. Another bacterial strategy that contributes to their capacity to withstand antimicrobials is the formation of biofilms. Biofilms are associations of microorganisms embedded a self-produced extracellular matrix. They create particular environments that confer bacterial tolerance and resistance to antibiotics by different mechanisms that depend upon factors such as biofilm composition, architecture, the stage of biofilm development, and growth conditions. The biofilm structure hinders the penetration of antibiotics and may prevent the accumulation of bactericidal concentrations throughout the entire biofilm. In addition, gradients of dispersion of nutrients and oxygen within the biofilm generate different metabolic states of individual cells and favor the development of antibiotic tolerance and bacterial persistence. Furthermore, antimicrobial resistance may develop within biofilms through a variety of mechanisms. The expression of efflux pumps may be induced in various parts of the biofilm and the mutation frequency is induced, while the presence of extracellular DNA and the close contact between cells favor horizontal gene transfer. A deep understanding of the mechanisms by which biofilms cause tolerance/resistance to antibiotics helps to develop novel strategies to fight these infections.
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Simões, Lúcia Chaves, Manuel Simões et Maria João Vieira. « Influence of the Diversity of Bacterial Isolates from Drinking Water on Resistance of Biofilms to Disinfection ». Applied and Environmental Microbiology 76, no 19 (6 août 2010) : 6673–79. http://dx.doi.org/10.1128/aem.00872-10.
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ABSTRACT Single- and multispecies biofilms formed by six drinking water-isolated bacterial species were used to assess their susceptibilities to sodium hypochlorite (SHC). In general, multispecies biofilms were more resistant to inactivation and removal than single biofilms. Total biofilm inactivation was achieved only for Acinetobacter calcoaceticus single-species biofilms and for those multispecies biofilms without A. calcoaceticus. Biofilms with all bacteria had the highest resistance to SHC, while those without A. calcoaceticus were the most susceptible. A. calcoaceticus formed single biofilms susceptible to SHC; however, its presence in multispecies biofilms increased their resistance to disinfection.
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Yadav, Puja, Shalini Verma, Richard Bauer, Monika Kumari, Meenakshi Dua, Atul Kumar Johri, Vikas Yadav et Barbara Spellerberg. « Deciphering Streptococcal Biofilms ». Microorganisms 8, no 11 (21 novembre 2020) : 1835. http://dx.doi.org/10.3390/microorganisms8111835.
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Streptococci are a diverse group of bacteria, which are mostly commensals but also cause a considerable proportion of life-threatening infections. They colonize many different host niches such as the oral cavity, the respiratory, gastrointestinal, and urogenital tract. While these host compartments impose different environmental conditions, many streptococci form biofilms on mucosal membranes facilitating their prolonged survival. In response to environmental conditions or stimuli, bacteria experience profound physiologic and metabolic changes during biofilm formation. While investigating bacterial cells under planktonic and biofilm conditions, various genes have been identified that are important for the initial step of biofilm formation. Expression patterns of these genes during the transition from planktonic to biofilm growth suggest a highly regulated and complex process. Biofilms as a bacterial survival strategy allow evasion of host immunity and protection against antibiotic therapy. However, the exact mechanisms by which biofilm-associated bacteria cause disease are poorly understood. Therefore, advanced molecular techniques are employed to identify gene(s) or protein(s) as targets for the development of antibiofilm therapeutic approaches. We review our current understanding of biofilm formation in different streptococci and how biofilm production may alter virulence-associated characteristics of these species. In addition, we have summarized the role of surface proteins especially pili proteins in biofilm formation. This review will provide an overview of strategies which may be exploited for developing novel approaches against biofilm-related streptococcal infections.
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Zhang, Qiuting, Jian Li, Japinder Nijjer, Haoran Lu, Mrityunjay Kothari, Ricard Alert, Tal Cohen et Jing Yan. « Morphogenesis and cell ordering in confined bacterial biofilms ». Proceedings of the National Academy of Sciences 118, no 31 (30 juillet 2021) : e2107107118. http://dx.doi.org/10.1073/pnas.2107107118.
Texte intégralRésumé :
Biofilms are aggregates of bacterial cells surrounded by an extracellular matrix. Much progress has been made in studying biofilm growth on solid substrates; however, little is known about the biophysical mechanisms underlying biofilm development in three-dimensional confined environments in which the biofilm-dwelling cells must push against and even damage the surrounding environment to proliferate. Here, combining single-cell imaging, mutagenesis, and rheological measurement, we reveal the key morphogenesis steps of Vibrio cholerae biofilms embedded in hydrogels as they grow by four orders of magnitude from their initial size. We show that the morphodynamics and cell ordering in embedded biofilms are fundamentally different from those of biofilms on flat surfaces. Treating embedded biofilms as inclusions growing in an elastic medium, we quantitatively show that the stiffness contrast between the biofilm and its environment determines biofilm morphology and internal architecture, selecting between spherical biofilms with no cell ordering and oblate ellipsoidal biofilms with high cell ordering. When embedded in stiff gels, cells self-organize into a bipolar structure that resembles the molecular ordering in nematic liquid crystal droplets. In vitro biomechanical analysis shows that cell ordering arises from stress transmission across the biofilm–environment interface, mediated by specific matrix components. Our imaging technique and theoretical approach are generalizable to other biofilm-forming species and potentially to biofilms embedded in mucus or host tissues as during infection. Our results open an avenue to understand how confined cell communities grow by means of a compromise between their inherent developmental program and the mechanical constraints imposed by the environment.
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Dasgupta, Mrinal K., et Marlene Larabie. « Biofilms in Peritoneal Dialysis ». Peritoneal Dialysis International : Journal of the International Society for Peritoneal Dialysis 21, no 3_suppl (décembre 2001) : 213–17. http://dx.doi.org/10.1177/089686080102103s37.
Texte intégralRésumé :
Microbial adhesions and biofilm bacterial growth have been implicated in serious infections associated with the use of bioprosthetic medical devices and indwelling catheters in humans. Biofilm bacterial growth also commonly occurs on peritoneal dialysis (PD) catheters from skin bacteria. Mature biofilms develop high antibiotic resistance and cause recurrent peritonitis and catheter loss in a subgroup of PD patients. That subgroup of patients can be identified by comparing the antibiotic sensitivities [minimum inhibitory concentrations (MICs)] of a biofilm culture and a routine microbiologic (planktonic) culture of the same PD effluent.
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BELLOWS, CHARLES, et ALISON SMITH. « In vitro study of Biofilm Growth on Biologic Prosthetics ». Polish Journal of Microbiology 63, no 4 (2014) : 409–14. http://dx.doi.org/10.33073/pjm-2014-055.
Texte intégralRésumé :
Biologic prosthetics are increasingly used for the repair of abdominal wall hernia defects but can become infected as a result of peri- or early post-operative bacterial contamination. Data evaluating biofilm formation on biologic prosthetics is lacking. The aim of this study was to investigate the influence of different biologic prosthetics on the growth behavior of two different bacterial species and their ability to form biofilms. Methicillin resistant Staphylococcus aureus (MRSA) or Pseudomrnonas aeruginosa were incubated on disks of two biologic prosthetics-human acellular dermis (ADM), and porcine small intestinal submucosa (SIS). The bacteria were allowed to attach to the prosthetics and propagate into mature biofilms for 24 hours at 370C. Images of biofilms were obtained using confocal microscopy and scanning electron microscopy (SEM). The number of viable cells and the biofilm biomass were quantified by colony forming units (CFUs) and crystal violet staining respectively. Analysis of variance was performed to compare the mean values for the different prosthetics. Each biologic matrix had a distinct surface characteristic. SEM visualized mature biofilms characterized by highly organized multi-cellular structures on surface of both biologic prosthetics. Quantification of bacterial growth over time showed that ADM had the lowest CFUs and biofilm biomass at 24 hours post-inoculation compared to SIS for both bacterial strains. MRSA and P. aeruginosa can form mature biofilms on biologic prosthetics but the relative abundance of the biofilm varies on different prosthetic constructs. Biologic material composition and manufacturing methods may influence bacterial adherence.
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Bhattacharya, Mohini, Evelien T. M. Berends, Rita Chan, Elizabeth Schwab, Sashwati Roy, Chandan K. Sen, Victor J. Torres et Daniel J. Wozniak. « Staphylococcus aureus biofilms release leukocidins to elicit extracellular trap formation and evade neutrophil-mediated killing ». Proceedings of the National Academy of Sciences 115, no 28 (25 juin 2018) : 7416–21. http://dx.doi.org/10.1073/pnas.1721949115.
Texte intégralRésumé :
Bacterial biofilms efficiently evade immune defenses, greatly complicating the prognosis of chronic infections. How methicillin-resistant Staphylococcus aureus (MRSA) biofilms evade host immune defenses is largely unknown. This study describes some of the major mechanisms required for S. aureus biofilms to evade the innate immune response and provides evidence of key virulence factors required for survival and persistence of bacteria during chronic infections. Neutrophils are the most abundant white blood cells in circulation, playing crucial roles in the control and elimination of bacterial pathogens. Specifically, here we show that, unlike single-celled populations, S. aureus biofilms rapidly skew neutrophils toward neutrophil extracellular trap (NET) formation through the combined activity of leukocidins Panton–Valentine leukocidin and γ-hemolysin AB. By eliciting this response, S. aureus was able to persist, as the antimicrobial activity of released NETs was ineffective at clearing biofilm bacteria. Indeed, these studies suggest that NETs could inadvertently potentiate biofilm infections. Last, chronic infection in a porcine burn wound model clearly demonstrated that leukocidins are required for “NETosis” and facilitate bacterial survival in vivo.
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Sionov, Ronit Vogt, et Doron Steinberg. « Targeting the Holy Triangle of Quorum Sensing, Biofilm Formation, and Antibiotic Resistance in Pathogenic Bacteria ». Microorganisms 10, no 6 (16 juin 2022) : 1239. http://dx.doi.org/10.3390/microorganisms10061239.
Texte intégralRésumé :
Chronic and recurrent bacterial infections are frequently associated with the formation of biofilms on biotic or abiotic materials that are composed of mono- or multi-species cultures of bacteria/fungi embedded in an extracellular matrix produced by the microorganisms. Biofilm formation is, among others, regulated by quorum sensing (QS) which is an interbacterial communication system usually composed of two-component systems (TCSs) of secreted autoinducer compounds that activate signal transduction pathways through interaction with their respective receptors. Embedded in the biofilms, the bacteria are protected from environmental stress stimuli, and they often show reduced responses to antibiotics, making it difficult to eradicate the bacterial infection. Besides reduced penetration of antibiotics through the intricate structure of the biofilms, the sessile biofilm-embedded bacteria show reduced metabolic activity making them intrinsically less sensitive to antibiotics. Moreover, they frequently express elevated levels of efflux pumps that extrude antibiotics, thereby reducing their intracellular levels. Some efflux pumps are involved in the secretion of QS compounds and biofilm-related materials, besides being important for removing toxic substances from the bacteria. Some efflux pump inhibitors (EPIs) have been shown to both prevent biofilm formation and sensitize the bacteria to antibiotics, suggesting a relationship between these processes. Additionally, QS inhibitors or quenchers may affect antibiotic susceptibility. Thus, targeting elements that regulate QS and biofilm formation might be a promising approach to combat antibiotic-resistant biofilm-related bacterial infections.