Influence of some plasma proteins on in vitro bacterial adherence to PTFE and Dacron vascular prostheses

Abstract

The in vitro adherence of Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli (one strain of each species) to commercially available, microporous polytetrafluoroethylene (PTFE) and woven Dacron vascular grafts before and after coating with human plasma was compared. Standard size segments of the materials were incubated with 35S-labeled bacteria for 0.5-18 h and, following washes, the radioactivity associated with the segment was measured. The binding of each of the tested species to native Dacron was higher than to PTFE. After coating with human plasma, however, the binding of all three species to PTFE was significantly enhanced, whereas the binding to Dacron was reduced. In addition, the influence of coating with serum albumin (HSA), immunoglobulin G (IgG), fibrinogen (Fg) or fibronectin (Fn) rather than whole plasma was tested. We found that coating with HSA reduced the binding of all three species to Dacron and of staphylococci to PTFE. IgG decreased the binding of S. epidermidis and E. coli to Dacron and of S. epidermidis to PTFE. In contrast, Fg enhanced the binding of S. aureus both to Dacron and PTFE, and that of E. coli to PTFE, but decreased the binding of S. epidermidis and E. coli to Dacron. Fn enhanced the binding of S. aureus to Dacron, and of E. coli to PTFE, but decreased the binding of S. aureus to PTFE and of S. epidermidis both to PTFE and Dacron. Thus, both whole plasma and some isolated plasma proteins were found to modulate bacterial adherence to two tested graft materials. From a clinical point of view, bacterial binding to plasma-coated rather than native materials may more adequately determine the likelihood of in vivo colonization of the various materials. Furthermore, precoating of materials with selected proteins may be of value in the prevention of graft colonization.