Studies on the interaction of staphylococcus aureus and staphylococcus epidermidis with fibronectin using surface plasmon resonance (BIAcore)

Abstract

This report provides a new technical approach for studying staphylococci adherence. The binding of staphylococci to fibronectin immobilised on a biosensor chip has been detected using surface plasmon resonance. Staphylococcus aureus had a much higher affinity for fibronectin than Staphylococcus epidermidis where binding could only be detected using the more sensitive BIAcore 2000. In the case of S. aureus a mutant strain which was defective in the expression of its fibronectin-binding proteins (Fbp's) was incapable of binding to fibronectin. In addition, the binding of whole cells of S. aureus to fibronectin was inhibited when the fibronectin coated biosensor chip was pre-treated with purified S. aureus FbpA. Surface plasmon resonance was also capable of studying bacterial interactions with intact or fragments of fibronectin and has shown that S. aureus preferentially binds to the N-terminal region whereas S. epidermidis binds to the C-terminal domain. BIAcore therefore provides us with an alternative method for comparing the interaction between bacteria and their isolated adhesin(s) for their affinities for a putative receptor which has been immobilised on the biosensor chip.