Inhibition by heparin and derivatized dextrans of Staphylococcus epidermidis adhesion to in vitro fibronectin-coated or explanted polymer surfaces

The ability of Staphylococcus aureus to recognize several extracellular mat rix or plasma proteins (e.g., fibrinogen, fibronectin, and collagen) promot es bacterial attachment to artificial surfaces. Whereas most S. aureus clin ical isolates elaborate a wide repertoire of bacterial surface 'receptors' called adhesins, exhibiting specific binding of individual host proteins, S . epidermidis is lacking most of such protein adhesins. To document the int eractions between, S. epidermidis and various surface-adsorbed proteins, we first compared promotion of bacterial attachment by seven purified human p roteins immobilized onto poly(methyl methacrylate) (PMMA) coverslips. Only two of them, namely fibronectin and fibrinogen, exhibited adhesion-promotin g activities. In the presence of native heparin or two functionalized dextr ans (CMDBS for Carboxy Methyl, Benzylamide sulfonate/sulfate), a dose-depen dent inhibition of S. epidermidis adhesion to fibronectin-coated, but not t o fibrinogen-coated surfaces was observed. The inhibitory effects of each C MDBS were much stronger than that of native heparin. In contrast, a control highly negatively charged dextran exclusively substituted with carboxy met hyl groups exerted no inhibition on S. epidermidis adhesion. To evaluate ho w CMDBS could interfere with S. epidermidis attachment to coverslips coated in vivo with extracellular matrix components, we also tested PMMA surfaces retrieved from tissue cages subcutaneously implanted in guinea pigs. Each CMDBS, but not heparin, strongly inhibited S. epidermidis adhesion to expla nted coverslips, even in the presence of tissue cage fluid. In conclusion, fibronectin plays an important role in promoting S. epidermidis attachment to implanted biomaterials. Furthermore, S. epidermidis adhesion to fibronec tin-coated or implanted biomaterials can be efficiently blocked in vitro by CMDBS.