Vitronectin may mediate staphylococcal adhesion to polymer surfaces in perfusing human cerebrospinal fluid.

Abstract

Prosthetic devices are frequently used for temporary or permanent drainage of cerebrospinal fluid (CSF), i.e., ventricular catheters with or without external monitoring devices and shunts. Infections constitute a serious complication in the use of biomaterials in contact with CSF; coagulase-negative staphylococci (CNS) are the most common aetiological agents. In the present study, polyvinylchloride (PVC) and PVC with endpoint-attached heparin were exposed to human CSF under perfusion to mimic conditions in vivo. Adhesion of strains of CNS isolated from patients with or without biomaterial-associated infection was determined: (i) after pre-incubation with fibronectin (Fn) or vitronectin (Vn) to block bacterial surface binding structures; and (ii) after preincubation of biomaterials with antibodies to Fn or Vn to block exposure of bacteria-binding domains on these host proteins. Pre-incubation of bacterial cells with Vn significantly reduced subsequent adhesion to polystyrene precoated with Vn 0.5 microg/well. When PVC pre-exposed to CSF was incubated with antibodies to Vn, subsequent bacterial adhesion of a Vn-binding strain, S. epidermidis 5703, was significantly reduced. The study shows that Vn may mediate adhesion of CNS in the presence of CSF. However, strains retrieved from biomaterials did not express binding of Vn or Fn to a higher extent than non-biomaterial-associated strains. Expression of heparin binding under static conditions did not correlate with staphylococcal adhesion to heparinised polymers under perfusion with CSF. The extent of adhesion of staphylococci to heparinised PVC was either reduced or the same as to unheparinised PVC.