Regulation of virulence factors in Staphylococcus aureus is affected by salicylic acid.

LUCÍA P ALVAREZ; MARÍA SOL BARBAGELATA; CECILIA QUIROGA; AL CHEUNG; DANIEL SORDELLI; FERNANDA BUZZOLA

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2007

REGULATION OF VIRULENCE FACTORS IN IS AFFECTED BY SALICYLIC ACID STAPHYLOCOCCUS AUREU The ability of to adapt to different environments is due to a global regulatory network comprising the loci and amongst others. These regulators are involved in the control of the expression of several virulence factors such as adhesin, which is upregulated by . Salicylic acid (SAL) negatively affects the expression of bacterial virulence factors. The aim of this work was to study the effect of SAL on , and through expression systems including plasmids carrying a reporter gene (green fluorescent protein GFP) driven by target gene promoters as well as by quantitative real time PCR (qRTPCR). We demonstrated a reduced expression of transcript in mutant through fluorometric assays and RTPCR suggesting that MgrA is a positive regulator of this adhesin. After seven hours of growth, strains treated with SAL showed reduced expression of , none differences in and increased expression of as compared with non-treated controls in fluorometric assays. The qRTPCR data shows that SAL down-regulates while up regulating and (mean fold change in gene expression by SAL treatment. : 0.75 ± 0.09; : 1.58 ± 0.19; : 2.05 ± 0.59).Altogether these results show that SAL does affect and which would alter the expression of several virulence factors driven by these regulators and therefore pathogenesis of S. aureus