Vancomycin (VAN) and ciprofloxacine (CIP) enhance biofilm formation in Staphylococcus aureus

GORDIOLA, M; ALVAREZ, LP; BARBAGELATA MS; LATTAR SM; CERQUETTI, MC; SORDELLI, DO; BUZZOLA FR

Tucuman

Encuentro; 45th Annual Meeting Argentine Society for Biochemistry and Molecular Biology Research; 2009

Staphylococcus aureus is the causative agent of a diverse array of acute and chronic infections owing to its ability to attach to a surface and form a biofilm. Biofilm is a very important virulence factor and it is involved in the development of device-related infection and chronic infections of tissues. Biofilm in S. aureus may be produced in an ica-dependent or ica-independent way. Glycopeptide VAN has been used to treat serious infections caused by methicillin-resistant S. aureus strains due to the emergency of resistance to CIP. The aim of this work was to evaluate whether subinhibitory concentrations (SubMIC) of VAN and CIP affect the expression of S. aureus virulence factors. Biofilm formation in the Newman strain was enhanced after subMIC of VAN (p<0.0001) and CIP (p<0.0001) exposures as assessed by spectrophotometric measures. However, after subMIC exposure with those antibiotics we did not observe changes in ica expression. Moreover, subMIC of VAN and CIP were shown to enhance biofilm formation even in an ica-deficient strain. Altogether, our results demonstrate that subMIC of VAN and CIP enhance biofilm formation in an ica-independent way in the Newman strain of S. aureus