Salicylic Acid Diminishes Staphylococcus aureus Capsular Polysaccharide Type 5 Expression.

ALVAREZ, LP; BARBAGELATA, MS; CHEUNG, AL; SORDELLI, DO; BUZZOLA FR

Boston

Congreso; 108th Reunion Anual de la Sociedad Americana de Microbiología; 2008

American Society for Microbiology

S. aureus possesses the ability to adhere to and invade non-professional phagocytic cells. S. aureus can be surrounded by a capsular polysaccharide (CP), with serotypes 5 and 8 being the most prevalent in humans. The CP5(8) production is highly regulated by different global regulators (agr, arlRS, saeRS, sarA, mgrA) and transcriptional factor (óB). S. aureus CP5(8) expression is highly sensitive to several environmental signals. In particular, salicylic acid (SAL) has been shown to reduce staphylococcal virulence. We hypothesized that SAL may have a negative effect on CP expression, hence altering the capability of S. aureus to invade epithelial cells. Intracellular survival of S. aureus cultured with or without SAL (50 µg/ml) within MAC-T cells was investigated by a lysostaphin protection assay. Two hours post-infection, Newman strain pretreated with SAL (1.5x105 CFU/ml) showed a significantly higher ability to become internalized within MAC-T cells when compared with the Newman strain (7x104 CFU/ml, p