The fungal pathogen Candida albicans is a leading cause of device-associated and other nosocomial infections. The traits of biofilm formation and invasion into an underlying surface are important for Candida to cause disease. In this dissertation, I describe my work, which reveals a novel role for glycerol in C. albicans biofilm formation and hyphal invasion. Through genomewide expression profiling it was observed that glycerol biosynthetic genes were highly upregulated in biofilms relative to the planktonic (suspension) cultures. Consistent with this observation, cells in a biofilm also accumulated higher amounts of glycerol then non-biofilm cells. In order to study the impact of glycerol on biofilm formation I made a deletion mutant, rhr2Δ/Δ, in the gene encoding glycerol-3-phosphatase. Under in vitro conditions, the rhr2Δ/Δ mutant has reduced biofilm biomass and reduced adherence to silicone. The mutant is also severely defective in biofilm formation in the rat venous catheter model of biofilm
Biofilm formation on medical devices is a common cause of implant failure, especially regarding implants that breach the epithelial tissue, so-called transcutaneous implants. Nanotechnology and the development of new nanomaterials have given the opportunity to design nanotextured implant surfaces. Such surfaces have been studied using various in vitro methods showing that nanosized features strongly benefit bone cell growth. However, little is known on how nanostructured features affect biofilm formation. The aim of this study was therefore to examine the shape- and chemical-dependent effect of a nanostructured hydroxyapatite (HA) coating on the degree of Staphylococcus epidermidis biofilm formation. Three different types of nanosized HA particles having different shapes and calcium to phosphate ratios were compared to uncoated turned titanium using safranin stain in a biofilm assay and confocal laser scanning microscopy (CLSM) for assessment of biofilm biomass and bacterial volume, ...
Biofilm-associated infections are hard to treat because of their high antibiotic resistance and the presence of a very persistent subpopulation of bacteria. The second messenger molecule cyclic di-guanosine monophosphate (c-di-GMP) plays a very important role in this biofilm physiology. Here, we evaluated the role of YddV, an enzyme with a c-di-GMP synthesis function, in the formation and maturation of Escherichia coli biofilms. Our results suggest that YddV stimulates biofilm growth via its role in the production of c-di-GMP and this likely by influencing the production of matrix (e.g. poly-N-acetylglucosamine (PGA)). However, lowering the YddV expression did not alter the biofilm formation since there was no significant difference between the biofilm phenotypes of WT E. coli and YddV-knockout bacteria. Additionally, YddV expression had no significant influence on the amount of persister cells within the biofilm population, questioning the use of YddV as therapeutic target. (C) 2016 Published ...
Biofilms have been implicated as an important reservoir for pathogens and commensal enteric bacteria such as Escherichia coli in natural and engineered water systems. However, the processes that regulate the survival of E. coli in aquatic biofilms have not been thoroughly studied. We examined the effects of hydrodynamic shear and nutrient concentrations on E. coli colonization of pre-established Pseudomonas aeruginosa biofilms, co-inoculation of E. coli and P. aeruginosa biofilms, and P. aeruginosa colonization of pre-established E. coli biofilms. In nutritionally-limited R2A medium, E. coli dominated biofilms when co-inoculated with P. aeruginosa, and successfully colonized and overgrew pre-established P. aeruginosa biofilms. In more enriched media, P. aeruginosa formed larger clusters, but E. coli still extensively overgrew and colonized the interior of P. aeruginosa clusters. In mono-culture, E. coli formed sparse and discontinuous biofilms. After P. aeruginosa was introduced to these biofilms, E.
Staphylococcus aureus extracellular DNA (eDNA) plays a crucial role in the structural stability of biofilms during bacterial colonization; on the contrary, host immune responses can be induced by bacterial eDNA. Previously, we observed production of S. aureus thermonuclease during the early stages of biofilm formation in a mammalian cell culture medium. Using a fluorescence resonance energy transfer (FRET)-based assay, we detected thermonuclease activity of S. aureus biofilms grown in Iscoves modified Dulbeccos medium (IMDM) earlier than that of widely studied biofilms grown in tryptic soy broth (TSB). The thermonuclease found was Nuc1, confirmed by mass spectrometry and competitive Luminex assay. These results indicate that biofilm development in IMDM may not rely on eDNA for structural stability. A bacterial viability assay in combination with wheat germ agglutinin (WGA) staining confirmed the accumulation of dead cells and eDNA in biofilms grown in TSB. However, in biofilms grown in IMDM, ...
Biofilms are ubiquitous in aquatic environments. Biofilms have been shown to attract and harbor pathogens such as P. aeruginosa and Legionella pneumophila in premise plumbing system. The fact that biofilms can protect attached bacterial cells from disinfectants raises rudimentary questions regarding interactions of bacterial cells with biofilm surfaces. Consequently, the main objectives of this study were to: 1) investigate the mechanisms that govern E. coli S17, E. coli 14f and Legionella cells adhesion on clean PVC, copper and biofilms; 2) examine the role of disinfectants on biofilms structure and subsequent effect on bacterial adhesion. Mechanisms of three strains of bacteria attachment on biofilms grown on PVC and copper surfaces were investigated. Biofilms were grown in CDC reactors using different types of feed water such as groundwater, monochloramine-treated groundwater, dechlorinated tap water and tap water. Biofilm physical structure was characterized at micro- and meso-scales using ...
In the majority of cases, the surface-associated multicellular communities found in a wide variety of natural and pathogenic ecosystems are formed in the presence of multiple diverse species and genetically distinct strains. In recent years, well-controlled in vitro biofilm model systems have revealed a diversity of molecular mechanisms contributing to development and maturation of single-species biofilms. The mechanisms underlying the biofilm development in the presence of these multispecies consortia are expected to involve even higher degrees of complexity; however, our understanding of mixed-species biofilms is hampered by the limited number of model systems that have been applied to date. The goal of this study was to test the capacity of a simple in vitro model to reveal factors contributing to the formation of more complex biofilm communities. The suitability of this approach to high-throughput analyses was demonstrated with a systematic survey of a large collection of E. coli isolates ...
Microtiter plate-based bacterial biofilm assay is frequently used to study bacterial biofilm development and growth. While this assay is simple and relatively high-throughput, it frequently shows difficulty in establishing robust biofilm attachment in the wells. We report that the consistency of bacterial biofilm a
The oral microbial ecology is comprised of hundreds of bacterial species that co-exist as multispecies biofilms throughout a range of ecological niches in the oral cavity. However, little is known concerning the interactions of these complex biofilms with host cells. Objective: This study used a novel model of multispecies bacterial biofilms to stimulate oral epithelial cells and profile select cytokines and chemokines that contribute to the local inflammatory environment in the periodontium. Method: Three multispecies biofilms comprising Streptococcus gordonii/S. oralis/S. sanguinis, Sg/Fusobacterium nucleatum/Porphyromonas gingivalis and Sg/Actinomyces naeslundii/Fn were grown for 3 days on rigid gas permeable contact lens pre-coated with 1% fetal bovine serum. OKF4 oral epithelial cells were cultured in 48 well plates at 105 cells/well, which were challenged with the biofilms for 24 hrs. Controls included incubation of the epithelial cells alone or overlaid with contact lens alone. A profile ...
Cells in bacterial biofilms are often less susceptible to host immune responses and antibiotics than cells grown in suspension (18). Biofilms may also provide a protective environment for pathogens, which, when released from the biofilm, may result in contamination of drinking water and medical fluids in delivery devices such as dialysis machines, venous catheters, dental water lines, and airway ventilators. Life-threatening infection caused by Pseudomonas aeruginosa in cystic fibrosis patients is a well-known example (8). Since biofilm formation in itself can be considered a virulence factor, it is important to understand the mechanisms which influence biofilm accumulation, structure, and behavior. Both hydrodynamics and cell signaling have been found to influence the structure of P. aeruginosa PAO1 biofilms. Stoodley et al. (27) reported that, under conditions of low-shear laminar flow, the biofilm consisted of a monolayer of cells with mound-shaped circular microcolonies but under high-shear, ...
S. aureus is a frequent etiological agent of biofilm infections on indwelling devices and orthopedic implants (9, 36), and recent reports by our group and others have demonstrated that biofilms can skew the immune response to favor anti-inflammatory and profibrotic pathways, which likely contribute to biofilm persistence (17, 18). To overcome this immune deviation and provide a novel treatment strategy for biofilm infections, we augmented antimicrobial activity through the local administration of classically activated M1 MΦs or treatment with the CD88 agonist EP67, which invokes MΦ proinflammatory responses. Early administration of M1-activated MΦs or EP67 limited biofilm formation, and treatment of established biofilm infections with M1-activated MΦs also significantly reduced catheter-associated biofilm burdens. Based on this evidence, we have identified a novel therapeutic strategy to limit S. aureus catheter-associated biofilm infections by targeting MΦ activation, which may extend to ...
Fluorescently labelled latex microbeads were used to study the interaction of particles with Pseudomonas aeruginosa biofilms in a continuous flow annular reactor. Beads were readily distinguished and enumerated in both intact and disaggregated biofilm samples. The fraction of beads that attached to biofilm during a 24 h period ranged from 0.001 to 0.01 and was proportional to biofilm cell carbon and to the standard deviation of biofilm thickness. Microbeads added to biofilm of steady state thickness (30 μm) were observed to be located throughout the entire biofilm depth in 24 h. Many of the microbeads that attached to biofilm shortly after bacterial inoculation (thickness of 2 μm) remained near the substratum as cells grew past and covered them. Microbeads were observed near the biofilm-substratum interface for up to 5 days after bead addition. Beads formed aggregates on biofilms, but not in bulk water. Beads captured by biofilm remained in the reactor system longer than beads that never ...
S. mutans UA159 and its derivative mutant strain luxS- [54] were incubated in Brain Heart Infusion Broth (BHI, Difco Labs, Detroit, USA) at 37°C in 95% air/5% CO2 (v/v), with the addition of erythromycin (10 μg/ml) in the case of the luxS- strain. Cultures of S. mutans were diluted 1:50, inoculated into fresh BHI media and grown in polystyrene tubes for 24 h (37°C, 95% air/5% CO2 (v/v)) for planktonic culture generation. The biofilm of luxS- was grown in BHI with addition of erythromycin (10 μg/ml) in 20-mm diameter, 15-mm deep sterile polystyrene multidishes (NUNCLON-143982, Roskilde, Denmark), as described previously [14].. As biofilm thickness plays a crucial role in mature biofilm development, we generated biofilms of wild-type bacteria under controlled nutrition flow and controlled biofilm depth conditions, by using the constant depth film fermentor (CDFF) [55]. The rotating turntable in the CDFF contained 15 polytetrafluoroethylene (PTFE) pans, rotated under PTFE scraper bars that ...
It is clear from many investigations that biofilm-associated cells display high-level tolerance to many antibiotics and other antimicrobial agents, creating considerable problems in removing biofilms from both abiotic and biotic surfaces in various settings, including in patients with infections (6). However, it is less clear if antibiotic tolerance is a shared feature of all biofilm-associated cells or if this property is associated with only parts of the biofilm populations. It is also not clear whether the biofilm-associated antibiotic tolerance is a direct consequence of the biofilm lifestyle per se or whether indirect induction of tolerance occurs in ways similar to what may even be the case for planktonic cells grown under special conditions. In order to obtain a more direct identification of the survivors after antibiotic treatment of biofilms, it is necessary to visualize them in situ. In the present context, we found it particularly interesting to investigate whether the stalk- and ...
TY - JOUR. T1 - Signaling factor interactions with polysaccharide aggregates of bacterial biofilms. AU - Desalvo, Stephen C.. AU - Liu, Yating. AU - Choudhary, Geetika Sanjay. AU - Ren, Dacheng. AU - Nangia, Shikha. AU - Sureshkumar, Radhakrishna. PY - 2015/2/17. Y1 - 2015/2/17. N2 - Biofilms are surface-attached colonies of bacteria embedded in an extracellular polymeric substance (EPS). Inside the eukaryotic hosts, bacterial biofilms interact with the host cells through signaling factors (SFs). These signaling processes play important roles in the interaction between bacteria and host cells and the outcome of infections and symbiosis. However, how host immune factors diffuse through biofilms is not well understood. Here, we describe synergistic molecular dynamics and experimental approaches for studying the translocation of signaling factors through polysaccharide chain aggregates present in the extracellular matrix of bacterial biofilms. The effect of polysaccharide chain degradation on the ...
A key problem in understanding major transitions in evolution is the evolution of cooperation: how are mutants that exploit the benefits of cooperation without paying the costs (cheats) suppressed within populations? Biofilms, which display properties of both single cell and multicellular organisms, provide an excellent model system to address this question. Biofilms exhibit grouped population structure - they exist primarily as dense aggregates of cells called microcolonies. We aim to test the hypothesis that cell-grouping displayed by microcolonies in bacterial biofilms provides a mechanism to suppress cheats within the biofilm population. We are using the co-operative trait of siderophore production (an extracellular iron-chelating molecule) within Pseudomonas aeruginosa biofilms to investigate cooperation in biofilms. Under iron-limited conditions, production of siderophores enhanced wild type growth, but microcolonies containing GFP-tagged, pyoverdin-mutant cheats developed poorly. In ...
Introduction: The discovery of new antimicrobials derived from plants could aid in the management of biofilm-associated infections, including denture-induced stomatitis (DS). DS is an oral infection caused by Candida biofilms on the surfaces of poorly cleansed dentures. Effective treatment of DS requires the use of an appropriate denture cleanser and preferably one that exhibits antimicrobial properties. Objective: This study aimed to evaluate the anti-Candida and anti-biofilm efficacy of two essential plant oils from Cymbopogon winterianus (citronella) and Cinnamon cassia (cinnamon). Materials and methods: Minimum Inhibitory Concentrations (MICs) and Minimum Fungicidal Concentrations (MFCs) were determined by broth microdilution, whilst anti-biofilm activity was measured against mature (cultured for 72 h) biofilms on acrylic surfaces. Candida cell viability was assessed immediately (0 h) after treatment (T0) and 48 h after biofilm re-growth (T48). Biofilm structure was determined using Scanning ...
Biofilms are often responsible for the difficulties in the treatment of infectious diseases due to their properties that facilitate escape from antibiotic effect and their antiphagocytic effects. At least 65% of all infectious diseases are associated with biofilm-forming bacteria. As Staphylococcus aureus and Staphylococcus epidermidis are among the most common agents of hospital infections and the infections are mostly biofilm-related, they pose an important problem. In infectious isolates, the minimum biofilm eradication concentration (MBEK) values of biofilm forms are much higher than the minimum inhibition concentration (MIC) values of planktonic forms. This situation requires the use of much higher doses of antibiotics in the treatment of infections and causes an increase in antibiotic resistance. The N-acetylcysteine (NAC) molecule is known to be effective against biofilm by disrupting mature biofilms and reducing the adhesion of bacteria to surfaces. In this study, it was aimed to ...
The third chapter aimed to study the role of persisters in determining the spatial and temporal pattern of biofilm formation following antibiotic treatment. A key feature of biofilms thought to play a role in antimicrobial tolerance is their ability to develop discrete, differentiated microcolony structures during colonization of a surface - these foci within biofilms are highly recalcitrant towards antimicrobials yet the factors that determine their differentiation and growth are poorly understood. This chapter therefore aimed to study the role of persisters in the initiation of microcolony foci and in mediating regrowth of biofilms. In this work, biofilm initiation was studied under a variety of conditions including with or without exposure to lethal or sub-lethal antibiotic challenge and as expected persister cell populations were able to generate significantly more biomass than in biofilms formed from non-persister populations. Dual labelling experiments were also carried out, where mixed ...
Neisseria gonorrhoeae has been shown to form biofilms during cervical infection. Thus, biofilm formation may play an important role in the infection of women. The ability of N. gonorrhoeae to form membrane blebs is crucial to biofilm formation. Blebs contain DNA and outer membrane structures, which have been shown to be major constituents of the biofilm matrix. The organism expresses a DNA thermonuclease that is involved in remodeling of the biofilm matrix. Comparison of the transcriptional profiles of gonococcal biofilms and planktonic runoff indicate that genes involved in anaerobic metabolism and oxidative stress tolerance are more highly expressed in biofilm. The expression of aniA, ccp, and norB, which encode nitrite reductase, cytochrome c peroxidase, and nitric oxide reductase respectively, is required for mature biofilm formation over glass and human cervical cells. In addition, anaerobic respiration occurs in the substratum of gonococcal biofilms and disruption of the norB gene required ...
Oral candidosis is common in patients with diabetes mellitus, as yeasts, particularly Candida albicans, have the propensity to colonise, form biofilms and release hydrolytic enzymes which cause inflammation. This study aimed to investigate these characteristics in isolates from three groups of patients with type 1 diabetes: individuals with better controlled diabetes (BCD; a parts per thousand yen6 , 8%), individuals with poorly controlled diabetes (PCD; a parts per thousand yen8%) and non-diabetics (ND; HbA(1c) , 5.9%). The biomass (Bm), phospholipase (P-z), haemolysin (H-z) and proteinase (Pr-z) were assessed using a microtitre biofilm assay and agar-based hydrolytic enzyme assays. Biofilm formation was significantly increased in the PCD group compared to ND and BCD groups (P , 0.05). No significant differences in P-z levels were observed between groups, whereas both H-z and Pr-z were significantly greater in the diabetes groups than in the healthy control group (P , 0.05). Statistically ...
UC Los Angeles. Staphyloccocus epidermidis is a significant cause of hospital-acquired infections, specifically blood stream infections (BSI) that result from the use of long-term central catheter lines. The ability to form biofilms is a key factor in the pathogenesis of these infections, with significant variation of biofilm phenotype amongst clinically isolated strains. The catheter lumen is a dynamic microenvironment inherently characterized by fluidic forces, however, little is understood regarding their effects on biofilm formation. Using a parallel microfluidic bioreactor shear array we show that fluid shear stress induces formation of significantly more biofilm than static conditions in a subset of clinically isolated strains, implicating catheter operation as a factor in bacterial pathogenesis.. Analysis of well-defined laboratory ATCC strains showed that the microfluidic biofilm assay could differentiate between biofilm+ (strain 35984) and biofilm- (strain 12228) genotypes with high ...
Biofilms are communities of surface-adherent bacteria surrounded by secreted polymers known as the extracellular polymeric substance. Biofilms are harmful in many industries, and thus it is of great interest to understand their mechanical properties and structure to determine ways to destabilize them. By performing single particle tracking with beads of varying surface functionalization it was found that charge interactions play a key role in mediating mobility within biofilms. With a combination of single particle tracking and microrheological concepts, it was found that Escherichia coli biofilms display height dependent charge density that evolves over time. Statistical analyses of bead trajectories and confocal microscopy showed inter-connecting micron scale channels that penetrate throughout the biofilm, which may be important for nutrient transfer through the system. This methodology provides significant insight into a particular biofilm system and can be applied to many others to provide ...
Barsoukov E. and J.R. Macdonald (eds). 2005. Impedance Spectroscopy: Theory, Experiment and Applications, 2nded. John Wiley & Sons, Inc., Hoboken, NJ, USA.. Ben-Yoav H., A. Freemanb, M. Sternheimc and Y. Shacham-Dia-manda. 2011. An electrochemical impedance model for integrated bacterial biofilms. Electrochim. Acta. 56:7780-7786.. Bjarnsholt T., K. Kirketerp-Møller, P.Ø. Jensen, K.G. Madsen, R. Phipps, K. Krogfelt, N. Høibyand and M. Givskov. 2008. Why chronic wounds will not heal: a novel hypothesis. Wound Rep. Reg. 16:2-10.. Dominguez-Benetton X., S. Sevda, K. Vanbroekhovena. and D. Panta. 2012. The accurate use of impedance analysis for thestudy of microbial electrochemical systems. Chem. Soc. Rev. 41:7228-7246.. Flemming H., J. Wingender and U. Szewczyk (eds). 2008. Biofilm Highlights. Springer Series on Biofilm Vol. 5. Springer-Verlag, Berlin, Heidelberg.. Ge Y., T. Deng and X. Zheng. 2008. Dynamic monitoring of changes in endothelial cell-substrate adhesiveness during leukocyte adhesion ...
Biofilms are sessile communities of bacteria typically embedded in an extracellular polymeric matrix. Bacterial cells embedded in biofilms are inherently recalcitrant to antimicrobials, compared to cells existing in a planktonic state, and are notoriously difficult to eradicate once formed. Avenues to tackle biofilms thus far have largely focussed on attempting to disrupt the initial stages of biofilm formation, including adhesion and maturation of the biofilm. Such an approach is advantageous as the concentrations required to inhibit formation of biofilms are generally much lower than removing a fully established biofilm. The crisis of antibiotic resistance in clinical settings worldwide has been further exacerbated by the ability of certain pathogenic bacteria to form biofilms. Perhaps the most notorious biofilm formers described from a clinical viewpoint have been methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Pseudomonas aeruginosa, Gardnerella vaginalis and ...
Alexandru Mihai Grumezescu*, Carmen Mariana Chifiriuc: Prevention of Microbial Biofilms - the Contribution of Micro and Nanostructured Materials, Current Medicinal Chemistry, accepted, 2014.. EDITORIAL. Microbial biofilms are associated with drastically enhanced resistance to most of the antimicrobial agents and with frequent treatment failures, generating the search for novel strategies which can eradicate infections by preventing the persistent colonization of the hospital environment, medical devices or human tissues. Some of the current approaches for fighting biofilms are represented by the development of novel biomaterials with increased resistance to microbial colonization and by the improvement of the current therapeutic solutions with the aid of nano(bio)technology. This special issues includes papers describing the applications of nanotechnology and biomaterials science for the development of improved drug delivery systems and nanostructured surfaces for the prevention and treatment of ...
Staphylococcus aureus (S. aureus) is a gram positive pathogen known to cause multiple infectious diseases for both animal and humans, and is responsible for community-associated and nosocomial infections. S. aureus possess the ability to form biofilms, which have a profound ability to adapt and thrive in undesirable conditions as well as resist antibiotic treatment. Recent studies suggest that polymorphonuclear leukocytes are able to attack S. aureus biofilms, thus implying the innate immune system indeed has mechanisms to respond to S. aureus biofilms. We determined if shear affected both the structure of the biofilm as well as the number on PMNs adhering to the S. aureus biofilm, and quantify where these cells adhere with respect to the biofilm. We conclude that shear does not have a significant effect on the number of cells adhering, but affects the depth of penetration in a maturing S. aureus biofilm ...
Angela Costa, Filipe Mergulhão, Romain Briandet, Nuno Azevedo. It is all about location: how to pinpoint microorganisms and their functions in multispecies biofilms. Future Microbiology, Future Medicine, 2017, 12 (11), pp.987-999. ⟨10.2217/fmb-2017-0053⟩. ⟨hal-03031230⟩ ...
Elucidation of the communal behavior of microbes in mixed species biofilms may have a major impact on understanding infectious diseases and for the therapeutics. Although, the structure and the properties of monospecies biofilms and their role in disease have been extensively studied during the last decade, the interactions within mixed biofilms consisting of bacteria and fungi such as Candida spp. have not been illustrated in depth. Hence, the aim of this study was to evaluate the interspecies interactions of Pseudomonas aeruginosa and six different species of Candida comprising C. albicans, C. glabrata, C. krusei, C. tropicalis, C. parapsilosis, and C. dubliniensis in dual species biofilm development. A significant reduction in colony forming units (CFU) of C. parapsilosis (90 min), C. albicans and C. tropicalis (90 min, 24 h and 48 h), C. dubliniensis and C. glabrata, (24 h and 48 h) was noted when co-cultured with P. aeruginosa in comparison to their monospecies counterparts (P | 0.05). A
Despite considerable research, the biofilm-forming capabilities of Nitrosomonas europaea are poorly understood for both mono and mixed-species communities. This study combined biofilm assays and molecular techniques to demonstrate that N. europaea makes very little biofilm on its own, and relies on the activity of associated heterotrophic bacteria to establish a biofilm. However, N. europaea has a vital role in the proliferation of mixed-species communities under carbon-limited conditions, such as in drinking water distribution systems, through the provision of organic carbon via ammonia oxidation. Results show that the addition of nitrification inhibitors to mixed-species nitrifying cultures under carbon-limited conditions disrupted biofilm formation and caused the dispersal of pre-formed biofilms. This dispersal effect was not observed when an organic carbon source, glucose, was included in the medium. Interestingly, inhibition of nitrification activity of these mixed-species biofilms in the presence
Biofilm Eradication and Preventions presents the basics of biofilm formation on medical devices, diseases related to this formation, and approaches pharmaceutical researchers need to take to limit this problem. Split into three parts, the first deals with the development and characterization of biofilm on the surfaces of implanted or inserted medical devices. Questions as to why biofilms form over medical device surfaces and what triggers biofilm formation are addressed. In the second section, the author discusses biofilm-mediated chronic infections occurred in various organs (eyes, mouth, wounds) and pharmaceutical and drug delivery knowledge gained from research in these area. The third part explores pharmaceutical approaches like lipid-and polymer-based drug delivery carriers for eradicating biofilm on device-related infections. In addition, this section also explores the topic of novel small molecule (like iron and its complexes/metal chelators) and a quorum-sensing inhibitors to control ...
TY - CONF. T1 - Incorporation of chitosan in acrylic bone cement: effect on antibiotic release and bacterial biofilm formation.. AU - Brady, Aaron. AU - Tunney, Michael. AU - Dunne, Nicholas. PY - 2007. Y1 - 2007. KW - biofilm. KW - bone cement. M3 - Poster. T2 - Society for General Microbiology. Y2 - 1 March 2012 through 1 March 2012. ER - ...
TY - JOUR. T1 - The small molecule DAM inhibitor, pyrimidinedione, disrupts Streptococcus pneumoniae biofilm growth in vitro. AU - Yadav, Mukesh Kumar. AU - Go, Yoon Young. AU - Chae, Sung Won. AU - Song, Jae Jun. N1 - Publisher Copyright: © 2015 Yadav et al.. PY - 2015/10/2. Y1 - 2015/10/2. N2 - Streptococcus pneumoniae persist in the human nasopharynx within organized biofilms. However, expansion to other tissues may cause severe infections such as pneumonia, otitis media, bacteremia, and meningitis, especially in children and the elderly. Bacteria within biofilms possess increased tolerance to antibiotics and are able to resist host defense systems. Bacteria within biofilms exhibit different physiology, metabolism, and gene expression profiles than planktonic cells. These differences underscore the need to identify alternative therapeutic targets and novel antimicrobial compounds that are effective against pneumococcal biofilms. In bacteria, DNA adenine methyltransferase (Dam) alters ...
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Gregory Anderson, biology department at IUPUI, will present Molecular Insights into Bacterial Biofilm Formation in the Cystic Fibrosis Lung. Read more about Anderson at https://science.iupui.edu/people/anderson-gregory .
Biofilms can develop on almost any surface exposed to an aqueous environment. The biofilm systems that result can be used beneficially, as exemplified by fixed-film wastewater treatment processes (for example, trickling filters and rotating biological contactors). In addition, biofilms play a major positive role in stream purification processes. However, biofilms can be quite troublesome in certain engineering systems. In water distribution systems and heat transfer equipment, for example, biofilms can cause substantial energy losses resulting from increased fluid frictional resistance and increased heat transfer resistance. The significance of biofilm development on various processes is summarized ...
Escherichia coli C forms more robust biofilms than other laboratory strains. Biofilm formation and cell aggregation under a high shear force depend on temperature and salt concentrations. It is the last of five E. coli strains (C, K12, B, W, Crooks) designated as safe for laboratory purposes whose genome has not been sequenced. Here we present the complete genomic sequence of this strain in which we utilized both long-read PacBio-based sequencing and high resolution optical mapping to confirm a large inversion in comparison to the other laboratory strains. Notably, DNA sequence comparison revealed the absence of several genes thought to be involved in biofilm formation, including antigen 43, waaSBOJYZUL for lipopolysaccharide (LPS) synthesis, and cpsB for curli synthesis. The first main difference we identified that likely affects biofilm formation is the presence of an IS3-like insertion sequence in front of the carbon storage regulator csrA gene. This insertion is located 86 bp upstream of the csrA
Biofilms have been found to be involved in large percentages of all infections in the body. Chronic sinusitis patients undergoing surgery present with biofilms most of the time. The NIH estimates that 80% of all human infections have biofilm involvment. Other infectious processes in which biofilms have been implicated include common problems such as urinary tract infections, catheter infections, middle-ear infections, endocarditis, infections in cystic fibrosis, and infections of permanent indwelling devices such as joint prostheses and heart valves. More recently it has been noted that bacterial biofilms may impair cutaneous wound healing and reduce topical antibacterial efficiency in healing or treating infected skin wounds. Biofilms can also be formed on the inert surfaces of implanted devices such as catheters, prosthetic cardiac valves and intrauterine devices ...
The influence of growth history on biofilm morphology and microbial community structure is poorly studied despite its important role for biofilm development. Here, biofilms were exposed to a change in hydrodynamic conditions at different growth stages and we observed how biofilm age affected the change in morphology and bacterial community structure. Biofilms were developed in two bubble column reactors, one operated under constant shear stress and one under variable shear stress. Biofilms were transferred from one reactor to the other at different stages in their development by withdrawing and inserting the support medium from one reactor to the other. The developments of morphology and microbial community structure were followed by image analysis and molecular tools. When transferred early in biofilm development, biofilms adapted to the new hydrodynamic conditions and adopted features of the biofilm already developed in the receiving reactor. Biofilms transferred at a late state of biofilm development
In science-fiction movies, force fields always come in handy when the good guys need protection from hostile aliens or bug-eyed monsters.. Of course, these miraculous devices dont really exist. But some of Earths simplest life forms protect themselves using a similar principle.. Many one-celled organisms secrete protein complexes called biofilms that serve as slimy barriers to the outside world.. Usually, biofilms dont pose any threat to human health. But theres increasing evidence that links them to antibiotic-resistant bacterial infections.. A recent study in the Journal of the American Medical Association suggests biofilms may help some middle-ear infections resist treatment efforts.. The study involved twenty-six children who suffered recurring bouts of otitis media [oh-TIGHT-iss MEE-dee-uh], one of the most common childhood ailments.. Researchers wanted to know if biofilms were protecting the bacteria that cause these infections. So they analyzed tissue samples collected from the middle ...
Dr. Eva Sapi sent us her teams new study that was partially funded by Lyme Warrior!In the past, solutions to Lyme disease have been limited partially because we cannot see or understand how biofilms react to treatment. Sapis team has uncovered a way to study the effect of ALL treatment methods on biofilms to help patients…
Fungal biofilms were more resistant to antimicrobial agents than planktonic cells. Four distinct growth phases in relation to antifungal susceptibility were examined. Our results demonstrated that all three strains became increasingly resistant to antifungal agents throughout morphological differentiation, which was consistent with the report by Imamura et al., 10 showing that Fusarium biofilms exhibited reduced susceptibility to lens care solutions in a time-dependent manner. Moreover, our results showed that the mature biofilms were intrinsically resistant to the azole antifungal drugs (FLU, VRC, and ITC). Multiple mechanisms have been proposed for the increased resistance of biofilms to antifungal agents. Our results indicate that ECM increased and a network of hyphal structures formed throughout the incubation time. The architecture of biofilms and the presence of ECM might reduce the diffusion of antifungal drugs, and they may be responsible for the increased resistance of biofilms to ...
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Organized within biofilm communities, bacteria exhibit resistance towards a broad spectrum of antibiotics. Thus, one might argue that bacteria isolated from biofilm-associated chronic infections should be subjected to resistance profiling under biofilm growth conditions. Various test systems have been developed to determine the biofilm-associated resistance; however, it is not clear to what extent the in vitro results reflect the situation in vivo, and whether the biofilm-resistance profile should guide clinicians in their treatment choice. To address this issue, we used confocal microscopy in combination with live/dead staining, and profiled biofilm-associated resistance of a large number (,130) of clinical Pseudomonas aeruginosa isolates from overall 15 cystic fibrosis patients. Our results demonstrate that in addition to a general non-responsiveness of bacteria when grown under biofilm conditions, there is an isolate-specific and antibiotic-specific biofilm-resistance profile. This individual ...
Micafungin (MFG) demonstrates potent activity against biofilms of Candida albicans and Candida parapsilosis, the most frequent opportunistic fungal pathogens. Little is known about its immunopharmacologic effect on antibiofilm activity of phagocytic cells following exposure to Candida biofilms. In this study, we investigated the effects of MFG on human neutrophil-mediated damage of C. albicans and C. parapsilosis biofilms by XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] and the potential mechanisms underlying the immunomodulatory MFG activities on cultured monocyte-derived THP-1 cells in response to these biofilms by reverse transcription-PCR and sandwich and multiplex enzyme-linked immunosorbent assay. Preexposure of C. albicans to subinhibitory MFG concentrations significantly enhanced neutrophil-mediated biofilm damage, an effect that appears to be species specific since a comparable effect was not observed with drug-pretreated C. parapsilosis biofilms. Human ...
During infection, fungi frequently transition to a biofilm lifestyle, proliferating as communities of surface-adherent aggregates of cells. Phenotypically, cells in a biofilm are distinct from free-floating cells. Their high tolerance of antifungals and ability to withstand host defenses are two characteristics that foster resilience. Biofilm infections are particularly difficult to eradicate, and most available antifungals have minimal activity. Therefore, the discovery of novel compounds and innovative strategies to treat fungal biofilms is of great interest. Although many fungi have been observed to form biofilms, the most well-studied is Candida albicans. Animal models have been developed to simulate common Candida device-associated infections, including those involving vascular catheters, dentures, urinary catheters, and subcutaneous implants. Models have also reproduced the most common mucosal biofilm infections: oropharyngeal and vaginal candidiasis. These models incorporate the ...
Genetic manage of candida albicans biofilm development. Genetic manipulate of candida albicans biofilm inside the improvement of candida albicans biofilms control in candida albicans and candida.. Plos one purpurin suppresses candida albicans biofilm. Purpurin suppresses candida albicans biofilm formation and hyphal development. Purpurin suppresses candida albicans genetic manage of candida albicans.. Genetics and genomics of candida albicans biofilm. Genetics and genomics of candida albicans biofilm formation. Genetic control of biofilm formation. Genes that govern candida albicans biofilm improvement.. Genetic control of candida albicans biofilm improvement. Genetic manipulate of candida albicans biofilm recognized the gene products that participate immediately inside the improvement of candida albicans biofilms,. Genetic manage of candida albicans biofilm development. Genetic manipulate of candida albicans biofilm improvement. (pmid21189476 pmcidpmc3891587) genetic control of candida albicans ...
Objective(s): Bacterial biofilm formation causes many persistent and chronic infections. The matrix protects biofilm bacteria from exposure to innate immune defenses and antibiotic treatments. The purpose of this study was to evaluate the biofilm formation of clinical isolates of Pseudomonas aeruginosa and the activity of zinc oxide nanoparticles (ZnO NPs) on biofilm. Materials and Methods: After collecting bacteria from clinical samples of hospitalized patients, the ability of organisms were evaluated to create biofilm by tissue culture plate (TCP) assay. ZnO NPs were synthesized by sol gel method and the efficacy of different concentrations (50- 350 µg/ml) of ZnO NPs was assessed on biofilm formation and also elimination of pre-formed biofilm by using TCP method.Results:The average diameter of synthesized ZnO NPs was 20 nm. The minimum inhibitory concentration of nanoparticles was 150- 158 μg/ml and the minimum bactericidal concentration was higher (325 µg/ml). All 15 clinical isolates of ...
The purpose of this study was to examine the effect of silver nanoparticles (SN) and nystatin on pre-formed biofilms (single and dual species combinations of Candida glabrata and Candida albicans). Thus, adhesion and biofilm assays were performed on acrylic surface in presence of artificial saliva (AS), during 2 h and 48 h, respectively. Candida glabrata and C. albicans adhered cells were determined by counting recovered colony forming units (CFUs) on CHROMagar® Candida. In addition, crystal violet (CV) staining, as an indicator of biomass, was used to quantify biofilm formation ability. Furthermore, pre-formed biofilms were treated either with SN or nystatin and its effects on biofilms evaluated after 24 h. The results showed that both Candidia species adhered to, and formed biofilms on acrylic. Candida glabrata biofilms had significantly higher CFUs compared with biofilms of C. albicans (P,0.05). In the case of dual species biofilms, the number of CFUs for each species was equivalent to that ...
This in vitro study evaluated the influence of chlorhexidine diacetate (CDA) when blended within dentin bonding systems (DBSs) on Streptococcus mutans (S. mutans) biofilm formation. One commercially available 0.2% wt CDA-containing DBS (Peak Universal Bond) and five experimental 0.2% wt CDA-containing DBS formulations (experimental Adper Scotchbond 1XT plus experimental resins, R2, R3, R4, R5) were assessed vs their no-CDA containing counterparts. Twenty-eight DBSs disks were prepared for each group (6.4 mm×1.0 mm) and cured for 80 s at 800 mW/cm2 in a nitrogen atmosphere. A modified Drip-Flow Reactor was used to grow S. mutans biofilms on specimen surfaces for 24 h and adherent, viable biomass was evaluated using a tetrazolium salt assay (MTT). Two specimens from each of the tested materials were processed with LIVE/DEAD stain and observed using laser confocal microscopy (CLSM) while two disks from each group were examined by using scanning electron microscopy (SEM). MTT assay, CLSM and SEM ...
Corrigendum: Anti-quorum Sensing and Anti-biofilm Activity of Delftia tsuruhatensis Extract by Attenuating the Quorum Sensing-Controlled Virulence Factor Production in Pseudomonas aeruginosaVijay K. Singh, Avinash Mishra* and Bhavanath Jha*Marine Biotechnology and Ecology Division, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, India* Correspondence: Avinash Mishra, [email protected]; [email protected]; [email protected] Bhavanath Jha, [email protected]: anti-biofilm, anti-quorum, microarray, quorum network, quorum quenching, quorum sensing, virulence factorsCorrigendum on: Singh VK, Mishra A and Jha B (2017) Anti-quorum Sensing and Anti-biofilm Activity of Delftia tsuruhatensis Extract by Attenuating the Quorum Sensing-Controlled Virulence Factor Production in Pseudomonas aeruginosa. Front. Cell. Infect. Microbiol. 7:337. doi: 10.3389/fcimb.2017.00337 Text CorrectionIn the original article, there was an error. ** SJ16 (1.0 mg/ml) **.A correction has
Biofilms are formed by a complex bacterial community encapsulated by a polymeric matrix, with strong adherent properties and persistent phenotype. Biofilms are considered one of the most challenging areas of modern medicine. Existing antibiotics have been developed against free-floating bacterial cells, and thus, many treatments of biofilm-related infection fail. In this study, we compared the effects of different media on biofilm growth of clinical reference strains of Staphylococci and Enterococci, including multi-drug resistant representatives. Further, we optimized the resazurin-based assay for determining the minimal biofilm inhibitory concentration (MBIC) of standard antibiotics, and evaluated its use for the determination of minimal biofilm eradication concentration (MBEC). We showed that tryptic soy broth supplemented with 1% glucose was an optimal media for maximum biofilm growth of all strains tested, with an extended incubation time for Enterococci. A range of parameters were tested for the
Stenotrophomonas maltophilia, an opportunistic pathogen usually connected with healthcare-associated infections, is an environmental bacterium. Intrinsic resistance to multiple antibiotics, with different virulence determinants in the last decade classified this bacterium in the group of global multiple drug resistant (MDR) organism. S. maltophilia clinical isolates, were collected from tertiary care pediatric hospital in Belgrade, Serbia to investigate influence of different factors on biofilm formation, kinetics of biofilm formation for strong biofilm producers and effect of trimethoprim-sulfamethoxazole (TMP/SMX) on formed biofilm. Most of the isolates (89.8%) were able to form a biofilm. Analysis of biofilm formation in different growth conditions showed that changing of temeperature and pH had the stronggest effect on biofilm formation almost equally in group of cystic fibrosis (CF) and non-CF strains. TMP/SMX in concentration of 50 μg/ml reduced completely 24 h old biofilms while ...
The success of Pseudomonas aeruginosa in cystic fibrosis (CF) and other chronic infections is largely attributed to its ability to grow in antibiotic-resistant biofilm communities. This study investigated the effects of limiting iron levels as a strategy for preventing/disrupting P. aeruginosa biofilms. A range of synthetic and naturally occurring iron-chelating agents were examined. Biofilm development by P. aeruginosa strain PAO1 and CF sputum isolates from chronically infected individuals was significantly decreased by iron removal under aerobic atmospheres. CF strains formed poor biofilms under anaerobic conditions. Strain PAO1 was also tested under anaerobic conditions. Biofilm formation by this model strain was almost totally prevented by several of the chelators tested. The ability of synthetic chelators to impair biofilm formation could be reversed by iron addition to cultures, providing evidence that these effective chelating compounds functioned by directly reducing availability of iron to P.
Owing to their massive use, Staphylococcus epidermidis has recently developed significant resistance to several antibiotics, and became one of the leading causes of hospital-acquired infections. Current antibiotics are typically ineffective in the eradication of bacteria in biofilm-associated persistent infections. Accordingly, the paucity of effective treatment against cells in this mode of growth is a key factor that potentiates the need for new agents active in the prevention or eradication of biofilms. Daptomycin and linezolid belong to the novel antibiotic therapies that are active against gram-positive cocci. on the other hand, rifampicin has been shown to be one of the most potent, prevalent antibiotics against S. epidermidis biofilms. Therefore, the main aim of this study was to study the susceptibility of S. epidermidis biofilm cells to the two newer antimicrobial agents previously mentioned, and compare the results obtained with the antimicrobial effect of rifampicin, widely used in ...
July 19, 2017 at 6:53 pm Front. Microbiol. 23 January 2017 Cristian Dotto1, Andrea Lombarte Serrat1, Natalia Cattelan2, María S. Barbagelata1†, Osvaldo M. Yantorno2, Daniel O. Sordelli1, Monika Ehling-Schulz3, Tom Grunert3 and Fernanda R. Buzzola1*. 1 Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina. 2 Facultad de Ciencias Exactas, Centro de Investigación y Desarrollo de Fermentaciones Industriales (CINDEFI), Centro Científico Technológico Consejo Nacional de Investigaciones Científicas y Tócnicas (CTT CONICET La Plata), Universidad Nacional de La Plata, La Plata, Argentina. 3 Functional Microbiology, Institute for Microbiology, University of Veterinary Medicine, Vienna, Austria. Aspirin has provided clear benefits to human health. But salicylic acid (SAL) ...
To evaluate the ability of the broad-spectrum lantibiotic, lacticin 3147, to prevent Streptococcus mutans biofilm formation and disrupt existing biofilms. Minimum inhibitory concentrations (MIC) and minimum biofilm inhibitory concentrations of purified lacticin 3147 were determined using a microdilution method. Lacticin 3147 effectively inhibited planktonic Strep. mutans, with MIC of 1.9-3.8 μmol l(-1). Time-kill kinetic studies confirmed that lacticin 3147 exhibited bactericidal activity against Strep. mutans at 38 μmol l(-1) (or 10× MIC). The effect of lacticin 3147 on biofilm formation and reduction was also determined. Exposure to 6.3-μmol l(-1) lacticin 3147 (2× MIC) resulted in substantial reductions in Strep. mutans biofilm formation while lacticin 3147 was less effective against 1-day-old biofilms. Culture-based analyses revealed that lacticin 3147 (50 μmol l(-1)) significantly inhibited Streptococcus spp. present in human saliva (P < 0.05) with an approximate 4-log reduction in ...
Cronobacter sakazakii is an important foodborne pathogen that causes neonatal meningitis and sepsis, with high mortality in neonates. However, very little information is available regarding the pathogenesis of C. sakazakii at the genetic level. In our previous study, a cellulose biosynthesis-related gene (bcsR) was shown to be involved in C. sakazakii adhesion/invasion into epithelial cells. In this study, the detailed functions of this gene were investigated using a gene knockout technique. A bcsR knockout mutant (ΔbcsR) of C. sakazakii ATCC BAA-894 showed decreased adhesion/invasion (3.9-fold) in human epithelial cell line HCT-8. Biofilm formation by the mutant was reduced to 50% of that exhibited by the wild-type (WT) strain. Raman spectrometry was used to detect variations in biofilm components caused by bcsR knockout, and certain components, including carotenoids, fatty acids and amides, were significantly reduced. However, another biofilm component, cellulose, was increased in ΔbcsR, suggesting
Background and objectives: Quercus brantii subsp. persica is used in folk medicine to treat infections in Iran. There is not available report on the anti-biofilm activity of Quercus brantii subsp. persica. The aim of the present study was to investigate the effects of Quercus brantii subsp. persica against bacterial biofilms. Methods: Eighty biofilm producing strains of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa were collected. Quercus brantii subsp. persica fruits aqueous extraction (QBAE) was prepared though maceration method. Chemical analysis to distinguish the main components of the QBAE was carried out using thin-layer chromatography. The antibacterial effects of QBAE on bacterial isolates were determined by the Kirby-Bauer and broth microdilution methods. The antibiofilm effects of QBAE on bacterial isolates were determined using a microtiter assay. Results: The Quercus brantii subsp. persica exhibited bacterial growth inhibition and
Streptococcus pneumoniae forms biofilms, but little is known about its extracellular polymeric substances (EPS) or the kinetics of biofilm formation. A system was developed to enable the simultaneous measurement of cells and the EPS of biofilm-associated S. pneumoniae in situ over time. A biofilm reactor containing germanium coupons was interfaced to an attenuated total reflectance (ATR) germanium cell of a Fourier transform infrared (FTIR) laser spectrometer. Biofilm-associated cells were recovered from the coupons and quantified by total and viable cell count methods. ATR-FTIR spectroscopy of biofilms formed on the germanium internal reflection element (IRE) of the ATR cell provided a continuous spectrum of biofilm protein and polysaccharide (a measure of the EPS). Staining of the biofilms on the IRE surface with specific fluorescent probes provided confirmatory evidence for the biofilm structure and the presence of biofilm polysaccharides. Biofilm protein and polysaccharides were detected ...
Urinary tract infections (UTIs) are one of the most important causes of morbidity and health care spending affecting persons of all ages. Bacterial biofilms play an important role in UTIs, responsible for persistent infections leading to recurrences and relapses. UTIs associated with microbial biofilms developed on catheters account for a high percentage of all nosocomial infections and are the most common source of Gram-negative bacteremia in hospitalized patients. The purpose of this mini-review is to present the role of microbial biofilms in the etiology of female UTI and different male prostatitis syndromes, their consequences, as well as the challenges for therapy
Surface colonization and subsequent biofilm formation and development provide numerous advantages to microorganisms. On the other hand, biofilm formation is an energetically costly process and therefore must be tightly regulated and plastic, enabling biofilm bacteria to be responsive to the various environmental cues. The quorum sensing (QS) pathway of Vibrio cholerae activates the expression of VpsR, VpsT and AphA (the main activators of biofilm formation) at low cell density and HapR (the main repressor) at high cell density. At low cell density, biofilm genes, including Vibrio polysaccharide (VPS) biosynthesis genes and the major extracellular matrix genes RbmA, RbmC, and Bap1, are expressed. The QS pathway also leads to induction of virulence factors such as toxin coregulated pilus (TCP) and cholera toxin (CTX), essential for colonization of the host and enterotoxicity, respectively. The VarS/VarA signaling system responds to an unknown environmental cue and represses biofilm production by ...
This study aimed to select an isolate of Lactobacillus spp. from the leaves of Pandanus amaryllifolius with the potential for biofilm development to inhibit various types of food-borne spoilage and pathogenic bacteria. The applicability and usefulness of the newly isolated strain, denoted as Lb. plantarum PA21, were extended via its capacity to express heterologous protein. The imaged biofilms and cell count results showed differences during the biofilm maturation periods. The ability of bacteria to adhere to the abiotic surface in plastic microtiter plates was measured using a conventional biofilm assay. The method offers some advantages compared to the study of biofilm formation in flow cells, which is an alternative widely used method. Watnick and Kotler [29] showed that the microtiter plate assay can be utilized to distinguish true biofilm formation similar to the biofilm grown in flow cells. This method appeared attractive for obtaining quantitative results based on CFU and optical ...
The study of biofilm function, structure and microbial interactions might help to improve our understanding of biofilm wastewater treatment processes. However, few reports specifically address the influence of interactions within multispecies biofilms on microbial activity and biofilm composition. Thus, the relationship between biofilm formation, denitrification activity, phosphorus removal and the composition of extracellular polymeric substances (EPS), exopolysaccharides and the bacterial community was investigated using biofilms of denitrifying and phosphorus removing strains Comamonas denitrificans 110, Brachymonas denitrificans B79, Aeromonas hydrophila L6 and Acinetobacter calcoaceticus ATCC23055. Denitrification activity within the biofilms generally increased with the amount of biofilm while phosphorus removal depended on bacterial growth rate. Synergistic effects of co-growth on denitrification (B. denitrificans B79 and A. hydrophila L6) and phosphorus removal (C. denitrificans 110 with ...
Biofilms and Disease== Bacteria make biofilms, which contain a heterogeneous mixture of microorganisms attached to a surface [[#References,[12]]]. Biofilms offer bacteria protection from hostile environments [[#References,[3]]], promote efficient food storage and nutrient acquisition mechanisms, and encourage synergistic relationships for community benefit. Biofilms are involved in a variety of infectious diseases, causing persistent problems such as cystic fibrosis pneumonia, otitis media, urinary tract infections, and dental plaque formation [[#References,[12]]]. ===Dental Plaque and Disease=== Dental plaque is a biofilm of diverse bacteria and extracellular polymeric substances. It builds up over time and leads to dental caries and periodontal diseases such as gingivitis, a gum inflammation. As many as 400 species of bacteria have been associated with dental plaques, the most common being Streptococcus and Lactobacillus, which are associated with acid formation leading to tooth decay ...
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TY - BOOK. T1 - Biofilms, infection, and antimicrobial therapy. AU - Pace, John L.. AU - Rupp, Mark E.. AU - Finch, Roger G.. PY - 2005/1/1. Y1 - 2005/1/1. N2 - Rather than existing in a planktonic or free-living form, evidence indicates that microbes show a preference for living in a sessile form within complex communities called biofilms. Biofilms appear to afford microbes a survival advantage by optimizing nutrition, offering protection against hostile elements, and providing a network for cell-to-cell signaling and genetic exchange. Biofilms, Infection, and Antimicrobial Therapy provides an in-depth exploration of biofilms, offering broad background information, as well a detailed look at the serious concerns to which biofilm-associated infections give rise. Prosthetic device infections, such as those involving artificial heart valves, intravascular catheters, or prosthetic joints, are prime examples of biofilm-associated infections. With the increasing use of such devices in the modern ...
This study aimed to develop improved cleaning strategies for controlling biofilms on the surfaces of membranes used in dairy ultrafiltration (UF) and reverse osmosis (RO) plants. Eleven UF / RO membrane modules from 7 different New Zealand dairy membrane processing plants were received after typical cleaning-in-place (CIP) procedures. Microorganisms were isolated from both the retentate and permeate sides of these membrane surfaces and from the liquids collected from a UF membrane plant. Also some foulants scraped from a RO membrane were tested. The routine CIP currently used in the dairy plants was not adequate to completely remove organic material, including microbial cells, proteins and carbohydrates from the membrane surfaces. These residues may influence the surface characteristics and interactions between microorganisms and membranes and thus affect biofilm formation. Thirteen isolates including both bacteria and yeast were identified using biochemical techniques. Klebsiella oxytoca were ...
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Antibiotic resistance is an ever-growing topic of concern within the medical field causing researchers to examine the mechanisms of resistance to develop new antimicrobials. Bacterias ability to form biofilms is one mechanism which aids in antimicrobial resistance. Staphylococcus aureus is of special interest as it is one of the most frequent biofilm-forming bacteria found on medical devices causing infections and posing dangerous threats in a clinical setting. A recently developed antimicrobial gel has been shown to have profound effects on treating bacterial infections and wound healing. This research is centered upon examining the antimicrobial effects of this gel on the three different stages of biofilm formation in clinical and laboratory strains of S. aureus. Through a series of experiments examining the effects this gel has on S. aureus at the stages of biofilm attachment, maturation, and dispersion, the gel has shown significant levels of inhibition. These findings indicate that the novel gel
Streptococcus pneumoniae and Staphylococcus aureus are ubiquitous upper respiratory opportunistic pathogens. Individually, these Gram-positive microbes are two of the most common causative agents of secondary bacterial pneumonia following influenza A virus infection, and they constitute a significant source of morbidity and mortality. Since the introduction of the pneumococcal conjugate vaccine, rates of cocolonization with both of these bacterial species have increased, despite the traditional view that they are antagonistic and mutually exclusive. The interactions between S. pneumoniae and S. aureus in the context of colonization and the transition to invasive disease have not been characterized. In this report, we show that S. pneumoniae and S. aureus form stable dual-species biofilms on epithelial cells in vitro. When these biofilms are exposed to physiological changes associated with viral infection, S. pneumoniae disperses from the biofilm, whereas S. aureus dispersal is inhibited. These ...
A team of researchers from the National University of Ireland in Galway has been investigating the effect of commonly used sanitising chemicals on Salmonella bacteria contained in biofilms on surfaces.. The researchers used a biofilm reactor to grow Salmonella biofilms and then tested the efficacy of three disinfectants, sodium hypochlorite, sodium hydroxide and benzalkonium chloride, against them. They tested both early (48 hours) and more established (168 hours) biofilms.. They found that all three chemicals reduced the viable count of Salmonella cells, but only sodium hydroxide could completely eradicate the early biofilm and none of the disinfectants could eradicate the mature biofilms, even after a 90-minute contact time. The ability to form resistant biofilms was shared by all the strains of Salmonella tested and they were able to colonise all surfaces, including glass, stainless steel and plastic.. The research team suggest that disinfectants used in food processing areas should be tested ...
This study distinguishes itself by comparing antibiotic activity against staphylococcal biofilms using not only an in vitro static model but also a dynamic model that takes into account the human pharmacokinetics of the drugs under study. Its originality also resides in the evaluation of antibiotic combinations in such a setting. The generated data highlight the possible interest of combining fusidic acid with daptomycin or linezolid in the context of biofilm-related infections.. Considering first the activity of antibiotics alone in the static biofilm model, we show here that it is globally rather poor, with a ,40% reduction in the viability signal being observed in most of the cases with drugs tested at clinically relevant concentrations. This is consistent with previous data obtained in the same model (28, 34). Since the intrinsic potency of the drugs against planktonic cultures (MIC values) are essentially of the same order of magnitude against all strains, the huge variation in activity of ...
Bacterial resistance to conventional antibiotics combined with an increasing acknowledgement of the role of biofilms in chronic infections has led to a growing interest in new antimicrobial strategies that target the biofilm mode of growth. In the aggregated biofilm mode, cell-to-cell communication systems involved in the process known as quorum sensing regulate coordinated expression of virulence with immune shielding mechanisms and antibiotic resistance. For two decades, the potential of interference with quorum sensing by small chemical compounds has been investigated with the aim of developing alternative antibacterial strategies. Here, we review state of the art research of quorum sensing inhibitors against the opportunistic human pathogen Pseudomonas aeruginosa, which is found in a number of biofilm-associated infections and identified as the predominant organism infecting the lungs of cystic fibrosis patients ...
article{3186904, abstract = {Salmonella enterica serovar Typhimurium is a main cause of bacterial food-borne diseases. As Salmonella can form biofilms in which it is better protected against antimicrobial agents on a wide diversity of surfaces, it is of interest to explore ways to inhibit biofilm formation. Brominated furanones, originally extracted from the marine alga Delisea pulchra, are known to interfere with biofilm formation in several pathogens. In this study, we have synthesized a small focused library of brominated furanones and tested their activity against S. enterica serovar Typhimurium biofilm formation. We show that several furanones inhibit Salmonella biofilm formation at non-growth-inhibiting concentrations. The most interesting compounds are (Z)-4-bromo-5-(bromomethylene)3- alkyl-2(5H)-furanones with chain lengths of two to six carbon atoms. A microarray study was performed to analyze the gene expression profiles of Salmonella in the presence of (Z)-4-bromo-5-(bromomethylene)3- ...
TY - JOUR. T1 - Microcontainer Delivery of Antibiotic Improves Treatment of Pseudomonas aeruginosa Biofilms. AU - Birk, Stine Egebro. AU - Haagensen, Janus Anders Juul. AU - Johansen, Helle Krogh. AU - Molin, Søren. AU - Nielsen, Line Hagner. AU - Boisen, Anja. PY - 2020. Y1 - 2020. N2 - Biofilm-associated infections are difficult to treat effectively with antibiotics despite repeated treatments. Polymeric microdevices (microcontainers) have previously been shown to engulf in mucus layers and to provide tunable release. Such devices may overcome the challenge of delivering antibiotics into the biofilm, increasing the local drug concentration and hence improve local bacterial killing. In this work, microcontainers are loaded with the antibiotic, ciprofloxacin hydrochloride, and functionalized with polymeric lids of polyethylene glycol (PEG), chitosan, or Eudragit S100. The PEG lid gives rise to a drug release comparable to uncoated microcontainers showing complete release after 8 h, whereas ...
Background & Objective: Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), represent serious nosocomial and community infections. Biofilm formation as an important virulence factor may be affected by sub-inhibitory levels of antibiotics. Few studies examined the effects of all therapeutic antimicrobial agents on clinical S.aureus. The current study aimed at observing the inducing and reducing effects of antibiotics, commonly used to treat staphylococcal infections on the production of staphylococcal biofilm. Methods: Four MRSA (1ATCC and 3 clinical) and 1 methicillin-susceptible Staphylococcus aureus (MSSA) strains with biofilm forming ability, evaluated by the Congo red agar (CRA) plate test, were employed. Biofilm formation was measured by crystal violet microtiter plate assay. Cefazolin, rifampicin, vancomycin, oxacillin, clindamycin, cotrimoxazole, minocycline, linezolid, azithromycin, and clarithromycin were added to wells ranging from 0.06to 128 µg/mL (1× to 1/1024 MIC
Paenibacillus polymyxa is a common soil bacterium with broad range of practical applications. An important group of secondary metabolites in P polymyxa are non-ribosomal peptide and polyketide derived metabolites (NRPs/PKs). Modular non-ribosomal peptide synthetases catalyze main steps in the biosynthesis of the complex secondary metabolites. Here we report on the inactivation of an A26 Sfp-type 4-phosphopantetheinyl transferase (Sfp-type PPTase). The inactivation of the gene resulted in loss of NRPs/PKs production. In contrast to the former Bacillus spp. model the mutant strain compared to wild type showed greatly enhanced biofilm formation ability. A26 Delta sfp biofilm promotion is directly mediated by NRPs/PKs, as exogenous addition of the wild type metabolite extracts restores its biofilm formation level. Wheat inoculation with bacteria that had lost their Sfp-type PPTase gene resulted in two times higher plant survival and about three times increased biomass under severe drought stress ...
Surface colonization and subsequent biofilm formation and development provide numerous advantages to microorganisms. On the other hand, biofilm formation is an energetically costly process and therefore must be tightly regulated and plastic, enabling biofilm bacteria to be responsive to the various environmental cues. The quorum sensing (QS) pathway of Vibrio cholerae activates the expression of VpsR, VpsT and AphA (the main activators of biofilm formation) at low cell density and HapR (the main repressor) at high cell density. At low cell density, biofilm genes, including Vibrio polysaccharide (VPS) biosynthesis genes and the major extracellular matrix genes RbmA, RbmC, and Bap1, are expressed. The QS pathway also leads to induction of virulence factors such as toxin coregulated pilus (TCP) and cholera toxin (CTX), essential for colonization of the host and enterotoxicity, respectively. The VarS/VarA signaling system responds to an unknown environmental cue and represses biofilm production by ...
Surface colonization and subsequent biofilm formation and development provide numerous advantages to microorganisms. On the other hand, biofilm formation is an energetically costly process and therefore must be tightly regulated and plastic, enabling biofilm bacteria to be responsive to the various environmental cues. The quorum sensing (QS) pathway of Vibrio cholerae activates the expression of VpsR, VpsT and AphA (the main activators of biofilm formation) at low cell density and HapR (the main repressor) at high cell density. At low cell density, biofilm genes, including Vibrio polysaccharide (VPS) biosynthesis genes and the major extracellular matrix genes RbmA, RbmC, and Bap1, are expressed. The QS pathway also leads to induction of virulence factors such as toxin coregulated pilus (TCP) and cholera toxin (CTX), essential for colonization of the host and enterotoxicity, respectively. The VarS/VarA signaling system responds to an unknown environmental cue and represses biofilm production by ...
Imbalances within the dental biofilm trigger dental caries, currently considered a dysbiosis and the most prevalent noncommunicable disease. There is still a gap in knowledge about the dynamics of enamel colonization by bacteria from the dental biofilm in caries. The aim, therefore, was to test whether the sequence of enamel colonization by a typically commensal and a cariogenic species modifies biofilms cariogenicity. Dual-species biofilms of Streptococcus mutans and Streptococcus sanguinis on saliva-coated enamel slabs were inoculated in different sequences: S. mutans followed by S. sanguinis (Sm-Ss), S. sanguinis followed by S. mutans (Ss-Sm), S. mutans and S. sanguinis inoculated at the same time (Sm=Ss), and the single-species controls S. mutans followed by S. mutans (Sm-Sm) and S. sanguinis followed by S. sanguinis (Ss-Ss). Biofilms were exposed to 10% sucrose 3 times per day for 5 days, and the slabs/biofilms were retrieved to assess demineralization, viable cells, biomass, proteins, ...
While studying virulence gene regulation in Vibrio cholerae during infection of the host small intestine, we identified VieA as a two-component response regulator that contributes to activating expression of cholera toxin. Here we report that VieA represses transcription of Vibrio exopolysaccharide …
A characteristic feature of biofilm formation is the production of a protective extracellular polymeric matrix. In the gram-positive bacterium Bacillus subtilis, the biofilm matrix is synthesized by the products of the epsABCDEFGHIJKLMNO operon (hereafter called the eps operon) and yqxM-sipW-tasA loci. Transcription from these operons is repressed by two key regulators, AbrB and SinR. Relief of inhibition is necessary to allow biofilm formation to proceed. Here we present data indicating that Abh, a sequence and structural homologue of AbrB, regulates biofilm architecture by B. subtilis when colony morphology and pellicle formation are assessed. Data indicating that abh expression is dependent on the environmental signals that stimulate the activity of the extracytoplasmic function sigma-factor sigma(X) are shown. We demonstrate that expression of slrR, the proposed activator of yqxM transcription, is positively controlled by Abh. Furthermore, Abh is shown to activate transcription from the ...
A biofilm is a complex community of cells enveloped in a self-produced polymeric matrix. Entry into a biofilm is exquisitely controlled at the level of transcription and in the Gram-positive organism Bacillus subtilis it requires the concerted efforts of three major transcription factors. Here, we demonstrate that in addition to transcriptional control, B. subtilis utilizes post-translational modifications to control biofilm formation; specifically through phosphorylation of tyrosine residues. Through our work we have assigned novel roles during biofilm formation to two proteins; the protein tyrosine kinase PtkA and the protein tyrosine phosphatase PtpZ. Furthermore by introducing amino acid point mutations within the catalytic domains of PtkA and PtpZ we have identified that the kinase and phosphatase activities, respectively, are essential for function. PtkA contains a conserved C-terminal tyrosine cluster that is the site of autophosphorylation; however, our in vivo analysis demonstrates that ...
Adhesion is a crucial initial step in microbial biofilm formation. Firm attachment to a target surface subsequently ensures successful colonization and survival despite turbulent conditions. In the laboratory, polystyrene plates are commonly used in biofilm experiments and the washing/rinse steps before staining are critical for assaying biofilm viability. However, these rinse steps risk the removal (partially or entirely) of the formed biofilm, resulting in inconsistent results. The aim of the present study was to optimize conditions for firmer biofilms, less prone to disruption and thus significantly reducing well-to-well variability. Candida albicans SC5314 was used in five different polystyrene 96-well plates from four different manufacturers. Irrespective of how gently we performed the rinse, biofilms came off certain polystyrene plates more easily compared to others. Importantly, preconditioning the polystyrene surfaces with foetal bovine serum (FBS) had a negative impact on firm biofilm ...
Biofilm formation by Staphylococcus epidermidis is a cause of infections related to peritoneal dialysis (PD). We have used a PD catheter flow-cell model in combination with confocal scanning laser microscopy and atomic force microscopy to study biofilm formation by S. epidermidis. Adherence to serum-coated catheters was four times greater than to uncoated ones, suggesting that S. epidermidis binds to serum proteins on the catheter surface. Pseudomonas aeruginosa biofilm supernatant interfered with the formation of a serum protein coat thereby reducing the capacity for biofilm formation in S. epidermidis. Supernatants from ΔpelA, ΔpslBCD and ΔrhlAB strains of P. aeruginosa showed no differences from the wild-type supernatant indicating that the effect on serum coat formation was not due to rhamnolipids or the PelA and PslBCD polysaccharides. Supernatant from P. aeruginosa also dispersed established S. epidermidis biofilms. Supernatants lacking PelA or PslBCD showed no differences from the wild ...
OBJECTIVE: To investigate the effect of cranberry extracts on saliva-derived polymicrobial biofilms with regards to biofilm biomass, acidogenicity, exopolysaccharide (EPS)/microbial biovolumes, colony forming unit (CFU) counts, and the relative abundance of specific caries- and health-associated bacteria.METHODS: Saliva-derived polymicrobial biofilms were grown for 96 h in a cariogenic environment and treated for 2 min every 12 h over the entire biofilm growth period with 500 mug/mL cranberry extract or vehicle control. The effect of the cranberry extract on biofilm behaviour was evaluated using different assays and its influence on key cariogenic and health-associated bacterial populations was assessed with a microarray real-time quantitative PCR method.RESULTS: Cranberry-treated biofilms showed significant drops in biomass (38% reduction, P , 0.001), acidogenicity (44% reduction, P , 0.001), EPS/microbial biovolume ratios (P = 0.033), and CFU counts (51% reduction, P = 0.001). Furthermore, the ...
Oxaran, V.; Dittmann, K.Kiesbye.; Lee, S.H.I.; Chaul, Líza.Toubas.; Fernandes de Oliveira, C.Augusto.; Corassin, C.Humberto.; Alves, Vínia.Farias.; De Martinis, E.Cristina.Pereira.; Gram, L., 2018: Behavior of Foodborne Pathogens Listeria monocytogenes and Staphylococcus aureus in Mixed-Species Biofilms Exposed to Biocides
Acinetobacter baumannii is an emerging nosocomial pathogen, responsible for infection outbreaks worldwide. The pathogenicity of this bacterium is mainly due to its multidrug-resistance and ability to form biofilm on abiotic surfaces, which facilitate long-term persistence in the hospital setting. Given the crucial role of iron in A. baumannii nutrition and pathogenicity, iron metabolism has been considered as a possible target for chelation-based antibacterial chemotherapy. In this study, we investigated the effect of iron restriction on A. baumannii growth and biofilm formation using different iron chelators and culture conditions. We report substantial inter-strain variability and growth medium-dependence for biofilm formation by A. baumannii isolates from veterinary and clinical sources. Neither planktonic nor biofilm growth of A. baumannii was affected by exogenous chelators. Biofilm formation was either stimulated by iron or not responsive to iron in the majority of isolates tested, ...
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