Influence of heparin coating on in vitro bacterial adherence to poly(vinyl chloride) segments

End-point attached, covalently bound heparin has been shown to be effective in preventing activation of the coagulation cascade by biomaterials. Data concerning its possible influence on bacterial attachment and resistance to biomaterial-associated infection are, so far, lacking. In the present work, the in vitro adherence of Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli, one isolate of each species, to plain poly(vinyl chloride) (plain PVC) and heparin coated poly(vinyl chloride) (EPA-PVC) segments was compared. Also, the influence of precoating the segments with human normal plasma for 2 h was studied. 35S-Methionine was used to radiolabel bacteria. The segments were exposed to bacterial suspensions of approximately 10(7) colony forming units (CFU) per milliliter at 37 degrees C for 0.5-6 h. Following repeated washing in phosphate buffered saline (PBS), radioactivity associated with the segments was measured. Plain PVC as compared to EPA-PVC bound significantly more cells of all three tested species. Plasma precoating significantly decreased adherence of the tested species to plain PVC but did not affect the binding to EPA-PVC. However, after precoating with human plasma, EPA-PVC compared to plain PVC showed a higher binding of S. aureus which might possibly be due to bridging effects of fibronectin or other plasma proteins, interacting with S. aureus.