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Biofilm Production (biofilm + production)
Selected Abstractsagr -Genotyping and transcriptional analysis of biofilm-producing Staphylococcus aureusFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1 2007Viviana Cafiso Abstract We investigated the correlation between biofilm production and the accessory-gene-regulator (agr) in 29 strains isolated from catheter-associated infections compared to a control group (30 isolates). All strains were tested for their ability to produce biofilm in a static system, and their agr genotype was determined. ScaI-restriction fragment length polymorphism for agr -typing showed that strong biofilm-producing strains belong to agr - type II. We found two new agr -variants, and sequence analysis of the three PCR products revealed the insertion of IS256 within the agr- locus. Biofilm production was assessed and correlated with agr functionality, with the expression of the ica -operon and of two transcriptional regulators, sarA and rsbU. Our data show that agr -II strains produce large amounts of biofilm, possess a defective agr -system show early transcription of icaA and are defective in haemolysin activity, icaR transcription, and in the expression of the ,B activator rsbU. Strains with agrIII are medium biofilm producers, have an inactive agr -system, but express icaAR and rsbU in the late- and postexponential growth phases. In agrI,IV- and -IA-variants, medium or weak biofilm production was found. In these strains, the agr -locus was fully functional, rsbU- icaR and icaA were found in the late- and/or postexponential phases. Biofilm production was not affected by sarA. [source] Biofilms in chronic bacterial prostatitis (NIH-II) and in prostatic calcificationsFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2010Sandra Mazzoli Abstract The prevalence of inflammatory conditions of the prostate gland is increasing. In Italy, there is a high incidence of prostatitis (13.3%), also accompanied by prostatic calcifications. Cat NIH-II chronic bacterial prostatitis (CBPs) are the most frequent. Their aetiology theoretically involves the whole range of bacterial species that are able to form biofilms and infect prostate cells. The aim of our study was to isolate potential biofilm-producing bacteria from CBP patients, to evaluate their ability to produce in vitro biofilms, and to characterize intraprostatic bacteria and prostatic calcifications using scanning electron microscopy. The 150 clinical bacterial strains isolated from chronic prostatitis NIH-II patients were: 50 Enterococcus faecalis; 50 Staphylococcus spp.; 30 Escherichia coli; 20 gram-negative miscellanea. Quantitative assay of biofilm production and adhesion was performed according to the classic Christensen microwell assay. Isolates were classified as nonproducers, weak, moderate or strong producers. The majority of E. coli, gram-negative bacteria, Staphylococci and Enterococci strains were strong or medium producers: 63,30%, 75,15%, 46,36%, and 58,14%, respectively. Prostatic calcifications consisted of bacteria-like forms similar to the species isolated from biological materials and calcifications of patients. Our study proves, for the first time, that bacterial strains able to produce biofilms consistently are present in CBP. Additionally, prostatic calcifications are biofilm-related. [source] agr -Genotyping and transcriptional analysis of biofilm-producing Staphylococcus aureusFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1 2007Viviana Cafiso Abstract We investigated the correlation between biofilm production and the accessory-gene-regulator (agr) in 29 strains isolated from catheter-associated infections compared to a control group (30 isolates). All strains were tested for their ability to produce biofilm in a static system, and their agr genotype was determined. ScaI-restriction fragment length polymorphism for agr -typing showed that strong biofilm-producing strains belong to agr - type II. We found two new agr -variants, and sequence analysis of the three PCR products revealed the insertion of IS256 within the agr- locus. Biofilm production was assessed and correlated with agr functionality, with the expression of the ica -operon and of two transcriptional regulators, sarA and rsbU. Our data show that agr -II strains produce large amounts of biofilm, possess a defective agr -system show early transcription of icaA and are defective in haemolysin activity, icaR transcription, and in the expression of the ,B activator rsbU. Strains with agrIII are medium biofilm producers, have an inactive agr -system, but express icaAR and rsbU in the late- and postexponential growth phases. In agrI,IV- and -IA-variants, medium or weak biofilm production was found. In these strains, the agr -locus was fully functional, rsbU- icaR and icaA were found in the late- and/or postexponential phases. Biofilm production was not affected by sarA. [source] Influence of temperature on biofilm formation by Listeria monocytogenes on various food-contact surfaces: relationship with motility and cell surface hydrophobicityJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2008G. Di Bonaventura Abstract Aims:, To assess the ability of Listeria monocytogenes to form biofilm on different food-contact surfaces with regard to different temperatures, cellular hydrophobicity and motility. Methods and Results:, Forty-four L. monocytogenes strains from food and food environment were tested for biofilm formation by crystal violet staining. Biofilm levels were significantly higher on glass at 4, 12 and 22°C, as compared with polystyrene and stainless steel. At 37°C, L. monocytogenes produced biofilm at significantly higher levels on glass and stainless steel, as compared with polystyrene. Hydrophobicity was significantly (P < 0·05) higher at 37°C than at 4, 12 and 22°C. Thirty (68·2%) of 44 strains tested showed swimming at 22°C and 4 (9·1%) of those were also motile at 12°C. No correlation was observed between swimming and biofilm production. Conclusions:,L. monocytogenes can adhere to and form biofilms on food-processing surfaces. Biofilm formation is significantly influenced by temperature, probably modifying cell surface hydrophobicity. Significance and Impacts of the Study:, Biofilm formation creates major problems in the food industry because it may represent an important source of food contamination. Our results are therefore important in finding ways to prevent contamination because they contribute to a better understanding on how L. monocytogenes can establish biofilms in food industry and therefore survive in the processing environment. [source] Detection by PCR of adhesins genes and slime production in clinical Staphylococcus aureusJOURNAL OF BASIC MICROBIOLOGY, Issue 4 2008Tarek Zmantar Abstract The presence of the ica loci and adhesins genes in clinical Staphylococcus aureus strains were considered important factors of virulence. In this study, 46 strains of Staphylococcus aureus were isolated from auricular infection, and were investigated for slime production using Congo Red Agar method (CRA). In order to detect the adhesins genes (ica A, ica D, fnb A, cna, Clf A) Polymerase Chain Reaction was used. Qualitative biofilm production of S. aureus using CRA plates revealed that 56.5% of strains were slime producers. In addition 78.26% of strains were ica A and ica D positive. While the fnbA gene was present in 76.1% of isolated strains. Furthermore, 56.5% of strains have the cna gene and 30.4% were clfA positives. Overall this study confirms the presence of fnb A and ica A/ica D genes in the majority of studies S. aureus strains isolated from Staphylococcal sepsis. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Quorum sensing controls biofilm formation in Vibrio choleraeMOLECULAR MICROBIOLOGY, Issue 1 2003Brian K. Hammer Summary Multiple quorum-sensing circuits function in parallel to control virulence and biofilm formation in Vibrio cholerae. In contrast to other bacterial pathogens that induce virulence factor production and/or biofilm formation at high cell density in the presence of quorum-sensing autoinducers, V. cholerae represses these behaviours at high cell density. Consistent with this, we show here that V. cholerae strains ,locked' in the regulatory state mimicking low cell density are enhanced for biofilm production whereas mutants ,locked' in the regulatory state mimicking high cell density are incapable of producing biofilms. The quorum-sensing cascade we have identified in V. cholerae regulates the transcription of genes involved in exopolysaccharide production (EPS), and variants that produce EPS and form biofilms arise at high frequency from non-EPS, non-biofilm producing strains. Our data show that spontaneous mutation of the transcriptional regulator hapR is responsible for this effect. Several toxigenic strains of V. cholerae possess a naturally occurring frameshift mutation in hapR. Thus, the distinct environments occupied by this aquatic pathogen presumably include niches where cell-cell communication is crucial, as well as ones where loss of quorum sensing via hapR mutation confers a selective advantage. Bacterial biofilms could represent a complex habitat where such differentiation occurs. [source] Inhibition of quorum-sensing signals by essential oilsPHYTOTHERAPY RESEARCH, Issue 5 2010Mira Ágnes Szabó Abstract The role of quorum sensing (QS) is well known in microbial pathogenicity and antibiotic resistance. QS is responsible for motility, swarming, and biofilm production based on the signal molecules, e.g., acylated homoserine lactones (AHLs) produced by micro-organisms above certain population density. The inhibition of QS may reduce pathogenicity, antibiotic resistance and biofilm formation in systemic and local infections. The homoserine lactones and other transmitters contribute to antibiotic resistance and pathogenicity of several bacteria; consequently the inhibition of QS signals reduces the problem of resistance and virulence. Due to the increasing number of persistent non-treatable infections, there is an urgent need to develop new strategies to combat infections that destabilize bacterial communities in the host. The effect of essential oils on bacterial growth and QS were evaluated using the sensor strain Chromobacterium violaceum CV026 and N -acyl homoserine lactone (AHL) producing Escherichia coli ATTC 31298 and the grapevine colonizing Ezf 10-17 strains. Of the tested oils, rose, geranium, lavender and rosemary oils were the most potent QS inhibitors. Eucalyptus and citrus oils moderately reduced pigment production by CV026, whereas the chamomile, orange and juniper oils were ineffective. Copyright © 2009 John Wiley & Sons, Ltd. [source] Clinical and Subclinical Endometritis in the Mare: Both Threats to FertilityREPRODUCTION IN DOMESTIC ANIMALS, Issue 2009MM LeBlanc Contents Endometritis, a major cause of mare infertility arising from failure to remove bacteria, spermatozoa and inflammatory exudate post-breeding, is often undiagnosed. Defects in genital anatomy, myometrial contractions, lymphatic drainage, mucociliary clearance, cervical function, plus vascular degeneration and inflamm-ageing underlie susceptibility to endometritis. Diagnosis is made through detecting uterine fluid, vaginitis, vaginal discharge, short inter-oestrous intervals, inflammatory uterine cytology and positive uterine culture. However, these signs may be absent in subclinical cases. Hypersecretion of an irritating, watery, neutrophilic exudate underlies classic, easy-to-detect streptococcal endometritis. In contrast, biofilm production, tenacious exudate and focal infection may characterize subclinical endometritis, commonly caused by Gram-negative organisms, fungi and staphylococci. Signs of subclinical endometritis include excessive oedema post-mating and a white line between endometrial folds on ultrasound. In addition, cultures of uterine biopsy tissue or of small volume uterine lavage are twice as sensitive as guarded swabs in detecting Gram-negative organisms, while uterine cytology is twice as sensitive as culture in detecting endometritis. Uterine biopsy may detect deep inflammatory and degenerative changes, such as disruption of the elastic fibres of uterine vessels (elastosis), while endoscopy reveals focal lesions invisible on ultrasound. Mares with subclinical endometritis require careful monitoring by ultrasound post-breeding. Treatments that may be added to traditional therapies, such as post-breeding uterine lavage, oxytocin and intrauterine antibiotics, include lavage 1-h before mating, carbetocin, cloprostenol, cervical dilators, systemic antibiotics, intrauterine chelators (EDTA,Tris), mucolytics (DMSO, kerosene, N -acetylcysteine), corticosteroids (prednisolone, dexamethasone) and immunomodulators (cell wall extracts of Mycobacterium phlei and Propionibacterium acnes). [source] Quantification of biofilm in microtiter plates: overview of testing conditions and practical recommendations for assessment of biofilm production by staphylococci,APMIS, Issue 8 2007SRDJAN STEPANOVI The details of all steps involved in the quantification of biofilm formation in microtiter plates are described. The presented protocol incorporates information on assessment of biofilm production by staphylococci, gained both by direct experience as well as by analysis of methods for assaying biofilm production. The obtained results should simplify quantification of biofilm formation in microtiter plates, and make it more reliable and comparable among different laboratories. [source] Surface modification of silicone intraocular lens by 2-methacryloyloxyethyl phosphoryl-choline binding to reduce Staphylococcus epidermidis adherenceCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 5 2007Xiao-Dan Huang MD Abstract Purpose:, To analyse the in vitro adherence of Staphylococcus epidermidis to the 2-methacryloyl oxyethyl phosphorylcholine (MPC)-modified silicone intraocular lens (IOL). Methods:, The test IOLs were modified by using an air plasma treatment to bind MPC to the surface. The control IOLs were not modified. Chemical changes on the IOL surface were analysed by X-ray photoelectron spectroscopy (XPS) to confirm the covalent binding of MPC. IOL hydrophilicity was determined by measuring the water contact angle. Two different techniques, direct counting of viable adherent bacteria released by sonication, and scanning electron microscopy (SEM), were used to observe and compare the adherence of S. epidermidis to the IOLs after 1- and 18-h incubation. Results:, XPS analysis confirmed that the test IOLs were surface-modified with MPC. The hydrophilicity of the IOLs was improved by surface modification, and the MPC-modified IOLs exhibited significantly reduced adhesion of S. epidermidis (P = 0.002) after an incubation period of 1 h. The SEM results showed that the MPC modification also suppressed the accumulation of bacteria and biofilm production after 18 h incubation. Conclusions:, MPC-modified hydrophilic silicone IOLs reduce bacterial adherence and colonization, and thus may help reduce the incidence of postoperative endophthalmitis. [source] Capacity of multidrug-resistant clinical isolates of Acinetobacter baumannii to form biofilm and adhere to epithelial cell surfacesCLINICAL MICROBIOLOGY AND INFECTION, Issue 1 2008H.-W. Lee Abstract This study evaluated the capacity of 23 multidrug-resistant (MDR) clinical isolates of Acinetobacter baumannii to adhere to respiratory epithelial cell surfaces and to form biofilm on a polystyrene surface. All 23 A. baumannii isolates were capable of adhering efficiently to respiratory epithelial cells, and biofilm production was positively associated with epithelial cell adhesiveness (r 0.80, p <0.0001). In the presence of the chelating agent EDTA, biofilm formation was markedly reduced. Cell adhesiveness and biofilm formation were significantly higher in isolates carrying the blaPER-1 gene as compared with isolates without this extended-spectrum ,-lactamase gene (p <0.005 and p <0.001, respectively). Further examination by RT-PCR showed a positive correlation between the level of expression of the blaPER-1 gene and the level of biofilm formation (r 0.89, p <0.0001) and cell adhesiveness (r 0.74, p <0.006). Overall, the study demonstrated a high capacity of clinical isolates of MDR A. baumannii to form biofilm and to adhere to respiratory epithelial cells. This feature, combined with multidrug resistance, might contribute to the survival of these organisms and their dissemination in the hospital environment. [source] |