The roles of capsular polysaccharide (CP) and the extracellular adhesion protein (Eap) in the internalization of Staphylococcus aureus

ALVAREZ LP, BARBAGELATA MS, SORDELLI DO AND BUZZOLA FR

Sapporo

Congreso; International Union of Microbiological Societies Congress; 2011

The pathogenesis of S. aureus is a complex phenomenon involving many virulence factors coordinatedly expressed during infection. Loss of CP expression facilitates S. aureus internalization into endothelial cells and Eap plays a significant role in adhesion of S. aureus to eukaryotic cells. The Sae regulatory system and the MgrA transcription factor upregulate Eap expression. This study investigated the role of CP, Eap and their main regulators Sae and MgrA in eukaryotic cell invasion by S. aureus. MAC-T epithelial cells were infected with suspensions of the following S. aureus strains: Newman (CP+), RN6390 (CP-), Reynolds CP+ and its isogenic CP-, AH12 (Newman eap-), Newman sae-, RN6390 sae- and Newman mgrA-. After 1 h incubation at 37ºC, the cell monolayers were washed with PBS and treated with lysostaphin. The resulting cell lysates were quantitatively plated to obtain the UFC/ml counts. The results of internalization into MAC-T cells were as follows: Newman: 8.5x104 vs. RN6390: 5x105 UFC/ml (*p