Enhancing effect of sub-inhibitory concentrations of vancomycin on biofilm formation by Staphylococcus aureus

DOTTO, CM; ALVAREZ, LP; BARBAGELATA, MS; SORDELLI, DO; BUZZOLA, FR

Recent Research Developments in Infection and Immunity

Transworld Research Network

Año: 2013; p. 1 - 18

Staphylococcus aureusis the causative agent of a broad spectrum of infections due to its ability to attach to damaged epithelia and inanimate surfaces, and to adopt a biofilm lifestyle. Biofilm is an essential virulence factor and it is involved in the development of device-related infections and chronic infections of diverse tissues. Low concentrations of certain antibiotics can affect the expression of bacterial virulence factors. The aim of the present study was to investigate the effect of subinhibitory concentrations of vancomycin (subVAN) on biofilm formation by S. aureusstrain Newman. The exposure of S. aureusto subVAN increased biofilm formation by the Newman strain and also by the S. aureus icaisogenic mutant; in the latter case, the biofilm was mainly composed by proteins. In addition, the subVAN exposure did not affect the biofilm formation by the isogenic saeRS mutant but biofilm formation was reduced by subVAN exposure in the Newman mgrA mutant. Moreover, the signal inducer subVAN provoked the waning of bacterial autolysis. Altogether, our observations suggest that subVAN enhances biofilm formation in an ica-independent manner in the S. aureusNewman strain.