Influence of salicylate on expression of Staphylococcus aureus extracellular adherence protein.

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

Cordoba

Congreso; 44th Annual Meeting, Argentine Society for Biochemistry and Molecular Biology Research; 2008

One of the most important adhesins in Staphylococcus aureus is the Extracellular Adherence Protein (Eap) which is found in 98% of clinical isolates. eap transcription is mainly regulated by sae. Several environmental signals affect virulence factors expression in S. aureus. In particular, salicylate (SAL) was shown to reduce staphylococcal virulence. The aim of this work was to study the effect of SAL on eap and sae and its consequences on internalization of S. aureus into MACT epithelial cells. We demonstrated that eap expression is enhanced after treatment with SAL through eap promoter fused to gfpuvr reporter gene. We also showed that levels of eap and sae transcripts were increased with SAL by Real-time PCR. Moreover, we observed the increase of Eap protein after SAL treatment. By fluorescence microscopy, we observed that eap expression is required to invade MACT cells and that SAL provoke a higher capability of internalization. Indeed, Newman strain pretreated with SAL (1.5x105 CFU/ml) showed a significantly higher ability to become internalized within epithelial cells when compared with the untreated strain (7x104 CFU/ml, p