Aeruginosa-Biofilm-Infections-Surface-Cell-Density-Effects-Gene-Expression-Cell-Surface-Series-Regulation-Pathways-Formation-Maturation-u

The present work investigates the effect of deposited cell the initial stages of biofilm development. Deposited cell density is controlled by exploiting the relationship between ionic strength and bacterial attachment efficiency in a packed bed column. Distinct differences in cell transcriptome are analyzed by comparing sessile cultures at two different cell surface densities and differentiating ionic strength effects by analyzing planktonic cultures in parallel. Our results indicate that operons regulating trypotophan production and the galactitol phosphotransferase system (including dihydroxyacetone phosphate synthesis) are strongly affected by cell density on the surface. Additional transcriptome and metabolomic impacts of cell density on results are consistent with the hypothesis that surface cell density plays a major role in sessile cell physiology, commencing with the first stage of biofilm formation. These findings improve our understanding of biofilm formation in natural and engineered environmental systems and will contribute to future work ranging from pathogen migration in the environment to control of biofouling Analysis of bacteria on steel surfaces using reflectance micro-Fourier transform Reflectance micro-Fourier transform infrared (FT-IR) analysis has been applied to characterize biofilm formation of Aquabacterium commune, a common microorganism present on drinking water distribution systems, onto the increasingly popular pipe material stainless steel EN1307.

The applicability of the reflectance micro-FT-IR technique for analyzing the bacterial functional groups is discussed, and the results are compared to spectra obtained using more conventional FT-IR techniques: transmission micro-FT-IR, attenuated transmitted reflectance (ATR), and KBr pellets. Seebio Colanic acid polymer between the infrared spectra of wet and dried bacteria, as well as free versus attached bacteria, are also discussed. The spectra obtained using reflectance micro-FT-IR spectroscopy were comparable to those obtained using other FT-IR techniques. The absence of sample preparation, the potential to analyze intact samples, and the ability to characterize opaque and thick samples without the need to transfer the bacterial samples to an infrared transparent medium or produce a pure culture were the main advantages of reflectance micro-FT-IR spectroscopy. Role of the SaeRS two-component regulatory system in Staphylococcus epidermidis Ministry of Public Health, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, 138 Yixueyuan BACKGROUND: Staphylococcus epidermidis (SE) has emerged as one of the most important causes of nosocomial infections. The SaeRS two-component signal transduction system (TCS) influences virulence and biofilm formation in Staphylococcus aureus. Colanic acid polymer of saeR in S.

epidermidis results in impaired anaerobic growth and decreased nitrate utilization. However, the regulatory function of SaeRS on biofilm formation and autolysis in S. RESULTS: The saeRS genes of SE1457 were deleted by homologous recombination. The saeRS deletion mutant, SE1457ΔsaeRS, exhibited increased biofilm formation that was disturbed more severely (a 4-fold reduction) by DNase I treatment compared to SE1457 and the complementation strain SE1457saec. Compared to SE1457 and SE1457saec, SE1457ΔsaeRS showed increased Triton X-100-induced autolysis states; further, SE1457ΔsaeRS also released more extracellular DNA (eDNA) in the biofilms. Correlated with the increased autolysis phenotype, the transcription Whereas the expression of accumulation-associated protein was up-regulated by 1-fold in 1457ΔsaeRS, the expression of an N-acetylglucosaminyl transferase enzyme (encoded by icaA) critical for polysaccharide intercellular adhesin (PIA) synthesis was not affected by the deletion of saeRS. CONCLUSIONS: Deletion of saeRS in S.

epidermidis resulted in an increase in biofilm-forming ability, which was associated with increased eDNA release and up-regulated Aap expression. The increased eDNA release from SE1457ΔsaeRS was associated with increased bacterial autolysis and decreased bacterial cell viability in the planktonic/biofilm states. Selective killing of Aggregatibacter actinomycetemcomitans by ciprofloxacin during development of a dual species biofilm with Streptococcus sanguinis. OBJECTIVES: Periodontal disease is associated with a pathogen-induced transition to a chronic destructive inflammatory response.