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Microbial Biofilms (microbial + biofilm)
Selected AbstractsMicrobial biofilms associated with biliary stent cloggingFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2010Emilio Guaglianone Abstract Endoscopic stenting is a palliative approach for the treatment of diseases involving biliary obstruction. Its major limitation is represented by stent occlusion, followed by life-threatening cholangitis, often requiring stent removal and replacement. Although it has been suggested that microbial colonization of biliary stents could play a role in the clogging process, the so far available data, particularly on the role of anaerobic bacteria, are not enough for a comprehensive description of this phenomenon. Our study was focused on the analysis of 28 explanted biliary stents by culturing, denaturing gradient gel electrophoresis and scanning electron microscopy to identify all the aerobic/anaerobic bacteria and fungi involved in the colonization of devices and to verify the ability of isolated anaerobic bacterial strains to form a biofilm in order to better understand the mechanisms of stent clogging. [source] Bacterial community structure, compartmentalization and activity in a microbial fuel cellJOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2006G.T. Kim Abstract Aims:, To characterize bacterial populations and their activities within a microbial fuel cell (MFC), using cultivation-independent and cultivation approaches. Methods and Results:, Electron microscopic observations showed that the fuel cell electrode had a microbial biofilm attached to its surface with loosely associated microbial clumps. Bacterial 16S rRNA gene libraries were constructed and analysed from each of four compartments within the fuel cell: the planktonic community; the membrane biofilm; bacterial clumps (BC) and the anode biofilm. Results showed that the bacterial community structure varied significantly between these compartments. It was observed that Gammaproteobacteria phylotypes were present at higher numbers within libraries from the BC and electrode biofilm compared with other parts of the fuel cell. Community structure of the MFC determined by analyses of bacterial 16S rRNA gene libraries and anaerobic cultivation showed excellent agreement with community profiles from denaturing gradient gel electrophoresis (DGGE) analysis. Conclusions:, Members of the family Enterobacteriaceae, such as Klebsiella sp. and Enterobacter sp. and other Gammaproteobacteria with Fe(III)-reducing and electrochemical activity had a significant potential for energy generation in this system. Significance and Impact of the Study:, This study has shown that electrochemically active bacteria can be enriched using an electrochemical fuel cell. [source] Relationship between periodontal infections and systemic diseaseCLINICAL MICROBIOLOGY AND INFECTION, Issue 2007G. J. Seymour Abstract Oral conditions such as gingivitis and chronic periodontitis are found worldwide and are among the most prevalent microbial diseases of mankind. The cause of these common inflammatory conditions is the complex microbiota found as dental plaque, a complex microbial biofilm. Despite 3000 years of history demonstrating the influence of oral status on general health, it is only in recent decades that the association between periodontal diseases and systemic conditions such as coronary heart disease and stroke, and a higher risk of preterm low birth-weight babies, has been realised. Similarly, recognition of the threats posed by periodontal diseases to individuals with chronic diseases such as diabetes, respiratory diseases and osteoporosis is relatively recent. Despite these epidemiological associations, the mechanisms for the various relationships remain unknown. Nevertheless, a number of hypotheses have been postulated, including common susceptibility, systemic inflammation with increased circulating cytokines and mediators, direct infection and cross-reactivity or molecular mimicry between bacterial antigens and self-antigens. With respect to the latter, cross-reactive antibodies and T-cells between self heat-shock proteins (HSPs) and Porphyromonas gingivalis GroEL have been demonstrated in the peripheral blood of patients with atherosclerosis as well as in the atherosclerotic plaques themselves. In addition, P. gingivalis infection has been shown to enhance the development and progression of atherosclerosis in apoE-deficient mice. From these data, it is clear that oral infection may represent a significant risk-factor for systemic diseases, and hence the control of oral disease is essential in the prevention and management of these systemic conditions. [source] Specificity in the settlement , modifying response of bacterial biofilms towards zoospores of the marine alga EnteromorphaENVIRONMENTAL MICROBIOLOGY, Issue 5 2003Pratixa Patel Summary Previous studies have shown that the rate of settlement of zoospores of the green alga Enteromorpha is stimulated by mixed microbial biofilms and that the number of zoospores settling is positively correlated with the number of bacteria in the biofilm. In the present study the specificity of this relationship has been investigated. Ninety-nine strains of marine bacteria were isolated from natural biofilms on rocks and the surface of Enteromorpha plants. Isolates were screened by denaturing gradient gel electrophoresis (DGGE) to eliminate replicates and 16S rDNA sequencing identified a total of 37 unique strains. Phylogenetic analysis revealed that the isolated bacterial strains belonged to three groups ,- Proteobacteria (28 strains), Cytophaga-Flavobacteria-Bacteroid (CFB) group (six strains) and ,- Proteobacteria (one strain). Two strains were unassigned, showing < 93% sequence similarity with the CFB group. The main genera of ,- Proteobacteria were Pseudoalteromonas (14 strains), Vibrio (five strains), Shewanella (five strains), Halomonas (three strains) and Pseudomonas (one strain). Spore settlement experiments were conducted on single-species biofilms, developed for different times on glass slides. The effect of correcting spore settlement values for biofilm density was evaluated. Results showed that the effect of bacterial strains on spore settlement was strain- but not taxon-specific and activity varied with the age of the biofilm. However, most of the strains belonging to genera Vibrio and Shewanella showed stimulation. Pseudoalteromonas strains showed a range of effects including settlement-inhibiting, paralysing and lysing activities. Spatial analysis of bacterial density in the presence and absence of spores revealed a range of different types of association between spores and bacteria. Overall, the spatial association between spores and bacteria appears to be independent of the overall quantitative influence of bacterial cells on spore settlement. [source] Acid microenvironments in microbial biofilms of antarctic endolithic microecosystemsENVIRONMENTAL MICROBIOLOGY, Issue 4 2003Asunción Los Ríos Summary Antarctic endolithic microecosystems harbour distinct biofilms. The lithic substrate and the microorganisms comprising these films are intimately linked, leading to complex mineral,microbe interactions. Hence, the microhabitats and microenvironments of these microecosystems are not only determined by the physicochemical features of the lithic substrate, but are also conditioned by the biological components of these biofilms. The Antarctic biofilms analysed in this study are characterized by the presence of extracellular polymer substances and acid microenvironments in the proximity of the cells; cyanobacteria appearing as key components. On ultrastructural analysis, these endolithic cyanobacteria showed differences in sheath organization, probably related to their spatial position in the lithic substrate. It is proposed that in this type of ecosystem, biofilm structure could favour the formation of microsites with specific physicochemical conditions appropriate for the survival of microbial communities in this extreme environment. [source] The first European congress on microbial biofilms: EUROBIOFILMS 2009, Rome, Italy, September 2,5, 2009FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2010Gianfranco Donelli Guest Editor First page of article [source] Sonic and ultrasonic scalers in periodontal treatment: a reviewINTERNATIONAL JOURNAL OF DENTAL HYGIENE, Issue 1 2007T Arabaci Abstract:, Periodontal therapy aims at arresting periodontal infection and maintaining a healthy periodontium. The periodic mechanical removal of subgingival microbial biofilms is essential for controlling inflammatory periodontal disease. Mechanical periodontal therapy consists of scaling, root planing and gingival curettage. The sonic and ultrasonic scalers are valuable tools in the prevention of periodontal disease. The vibration of scaler tips is the main effect to remove the deposits from the dental surface, such as bacterial plaque, calculus and endotoxin. However, constant flushing activity of the lavage used to cool the tips and cavitational activity result in disruption of the weak and unattached subgingival plaque. The aim of the study was to review the safety, efficacy, role and deleterious side-effects of sonic and ultrasonic scalers in mechanical periodontal therapy. [source] Effect of flow regimes on the presence of Legionella within the biofilm of a model plumbing systemJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2006Z. Liu Abstract Aims:, Stagnation is widely believed to predispose water systems to colonization by Legionella. A model plumbing system was constructed to determine the effect of flow regimes on the presence of Legionella within microbial biofilms. Methods and Results:, The plumbing model contained three parallel pipes where turbulent, laminar and stagnant flow regimes were established. Four sets of experiments were carried out with Reynolds number from 10 000 to 40 000 and from 355 to 2000 in turbulent and laminar pipes, respectively. Legionella counts recovered from biofilm and planktonic water samples of the three sampling pipes were compared with to determine the effect of flow regime on the presence of Legionella. Significantly higher colony counts of Legionella were recovered from the biofilm of the pipe with turbulent flow compared with the pipe with laminar flow. The lowest counts were in the pipe with stagnant flow. Conclusions:, We were unable to demonstrate that stagnant conditions promoted Legionella colonization. Significance and Impact of the Study:, Plumbing modifications to remove areas of stagnation including deadlegs are widely recommended, but these modifications are tedious and expensive to perform. Controlled studies in large buildings are needed to validate this unproved hypothesis. [source] Continuous long-term biotransformations using microbial biofilmsBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2010Article first published online: 20 JAN 2010 No abstract is available for this article. [source] | |||||||||||||