ULTRASTRUCTURAL ORGANIZATION AND REGULATION OF A BIOMATERIAL ADHESIN OF STAPHYLOCOCCUS-EPIDERMIDIS

Coagulase-negative staphylococci have emerged as important pathogens i n infections associated with intravascular devices. Microbial adherenc e to biomaterial surfaces is a crucial step in the pathogenesis of the se infections. Staphylococcal surface proteins (herein referred to as SSP-1 and SSP-2) are involved in the attachment of Staphylococcus epid ermidis 354 to polystyrene. In the present study we show that the adhe sin protrudes from the cell surface as a fimbria-like polymer. Further more, in vitro proteolytic cleavage of SSP-1 produces an SSP-2-like pr otein which coincides with a loss of adhesive function. SSP-1 expressi on is down-regulated in a phenotypical variant of S. epidermidis 354 w hereas SSP-2 expression is not. These results could suggest that prote olytic cleavage is a key to the regulation of the adhesive state of S. epidermidis in vivo.