Characterization of vitronectin-binding proteins of Staphylococcus epidermidis

Staphylococcus epidermidis is the most common microorganism that is isolate d from the cerebrospinal fluid (CSF) shunt infection patients. Vitronectin adsorbed on the surface of implants may mediate bacterial adhesion and colo nization. To characterize vitronectin-binding properties, we analyzed S. ep idermidis BD5703 isolated from a CSF shunt infection. Expression of vitrone ctin-binding protein(s) depended on culture media. Two proteins (60 and 52 kDa) were purified from vitronectin affinity chromatography. Two other vitr onectin-binding proteins (21 and 16 kDa) were purified from an ion-exchange column. All purified proteins blocked bacterial binding of immobilized vit ronectin significantly except the 16-kDa protein. The N-terminal sequences of the 21- and 16-kDa proteins did not show any appreciable amino acid sequ ence homology. The 52-kDa protein was sequenced by mass spectrometry and id entified as an autolysin. This report demonstrates that interaction of vitr onectin with multiple recognition sites on BD5703 surface may contribute to bacterial colonization.