Modification of the bacterial adhesion of Staphylococcus aureus by antioxidant blooming on polyurethane films

International audienceMedical device-related infections are a major problem in hospital. The risk of developing an infection is linked to the bacterial adhesion ability of pathogen strains on the device and their ability to form a biofilm. Here we focused on polymer surfaces exhibiting a blooming of antioxidant (Irganox 3114® and Irganox 1076®) on their surface. We tried to put into evidence the effect of such a phenomenon on the bacterial adhesion in terms of number of viable cultivable bacteria and bacteria localization on the surface. We showed that the blooming has a tendency to increase the Staphylococcus aureus adhesion phenomenon in part for topographic reasons

Surfaces bactériostatiques

National audienc

Impact of long-term starvation on adhesion to and biofilm formation on stainless steel 316 L and gold surfaces of Salmonella enterica serovar Typhimurium

International audienceThe objective of this study was to evaluate the effect of 3-year starvation in seawater microcosms on adhesion to and biofilm formation of two Salmonella enterica serovar Typhimurium strains on model stainless steel 316 L and gold surfaces. The bacteria were characterized in terms of morphological alteration, electrophoretic mobility, and affinity to various solvent interfaces. Scanning electron micrographs showed the appearance of coccoid and elongated cells after starvation. All stressed cells were characterized by a hyperflagellation, a significant increase in the global surface charge, and a conservation of their hydrophilic character. Epifluorescence microscopy highlighted an increase in the levels of adhered cells to stainless steel and gold surfaces after starvation stress. Confocal laser scanning microscopy produced evidence of variability between the three-dimensional biofilm architectures of the control and stressed cells on gold compared to stainless steel. The results obtained so far led us to hypothesize that the pervasiveness of nutrient deficiency in natural environments may generate new adaptation strategies for long-term starved Salmonella Typhimurium and probably create protection against other types of stress. The stress adaptation mechanisms identified in this study may induce a genetic instability and change virulence state of starved bacteria. This fundamental study provides information which may aid in the development of sanitation programs for effective pathogen removal in the food industry or from medical devices. The task is certainly complex given that several concomitant physicochemical parameters affect the adhesion to and biofilm formation on model surfaces of stressed bacteria

Robust Grafting of Polyionenes: New Potent and Versatile Antimicrobial Surfaces

International audiencePolyionenes (PI) with stable positive charges and tunable hydrophobic spacers in the polymer backbone, are shown to be particularly efficient regarding antimicrobial properties. This effect can be modulated since it increases with the length of hydrophobic spacers, i.e., the number of methylene groups between quaternary ammoniums. Now, to further explore these properties and provide efficient antimicrobial surfaces, polyionenes should be grafted onto materials. Here a robust grafting strategy to covalently attach polyionenes is described. The method consisted in a sequential surface chemistry procedure combining polydopamine coating, diazonium-induced polymerization, and polyaddition. To the best of knowledge, grafting of PI onto surfaces is not reported earlier. All chemical steps are characterized in detail via various surface analysis techniques (FTIR, X-ray photoelectron spectroscopy, contact angle, and surface energy measurements). The antibacterial properties of polyionene-grafted surfaces are then studied through bacterial adhesion experiments consisting in enumeration of adherent bacteria (total and viable cultivable cells). PI-grafted surfaces are showed to display effective and versatile bacteriostatic/bactericidal properties associated with a proadhesive effect

Ann. microbiol.

Purpose Brettanomyces bruxellensis is a serious source of concern for winemakers. The production of volatile phenols by the yeast species confers to wine unpleasant sensory characteristics which are unacceptable by the consumers and inevitably provoke economic loss for the wine industry. This ubiquitous yeast is able to adapt to all winemaking steps and to withstand various environmental conditions. Moreover, the ability of B. bruxellensis to adhere and colonize inert materials can be the cause of the yeast persistence in the cellars and thus recurrent wine spoilage. We therefore investigated the surface properties, biofilm formation capacity, and the factors which may affect the attachment of the yeast cells to surfaces with eight strains representative of the genetic diversity of the species.[br/] Methods The eight strains of B. bruxellensis were isolated from different geographical and industrial fermentation origins. The cells were grown in synthetic YPD medium containing 1% (w/v) yeast extract (Difco Laboratories, Detroit), 2% (w/v) bacto peptone (Difco), and 1% (w/v) glucose. Surface physicochemical properties as electrophoretic mobility and adhesion to hydrocarbon of the cells were studied. The ability of the strains to form biofilm was quantified using a colorimetric microtiter 96-well polystyrene plate. Biochemical characteristics were examined by colorimetric methods as well as by chemical analysis.[br/] Result Our results show that the biofilm formation ability is strain-dependent and suggest a possible link between the physicochemical properties of the studied strains and their corresponding genetic group.[br/] Conclusion The capacity to detect and identify the strains of the spoilage yeast based on their biofilm formation abilities may help to develop more efficient cleaning procedures and preventing methods