Adhesion of Staphylococcus epidermidis to surgical sutures

Objective: To investigate the interaction of Staphylococcus epidermidis with commonly used surgical sutures and the role of some of this bacterium virulence factors in this interaction. Summary Background Data: Coagulase negative staphylococci are ranked as the second most common cause of postoperative surgical site infections. Sutures have been suggested to act as adhesive surfaces that promote bacterial accumulation. Adherence of S. epidermidis and S. aureus to cardiac sutures has been suggested to be one of the explanations for these organisms being the commonest cause of early prosthetic valve endocarditis. Few S. epidermidis virulence factors have been identified and reported to be involved in this bacterium colonization of biomaterials and biofilm formation. Methods: Different strains of S. epidermidis were incubated with a number of commonly used sutures and examined for their capacity to bind to these sutures. The role of some of S. epidermidis virulence determinants thought to be important in adhesion to foreign bodies and host extracellular matrix proteins were analyzed for their role in the adhesion of this bacterium to sutures. Results: Adherence of S. epidermidis to sutures varied according to the type of material from which the suture was constructed and the strain of bacteria. The major adhesin responsible for binding to sutures was identified as the autolysin (AtlE) of this bacterium. S. epidermidis adhesion significantly increased when suture materials were coated with human plasma. Conclusions: S. epidermidis has a propensity to adhere to surgical sutures and this could increase the risk of wound infection and complications. The results of this study demonstrate that the choice of suture material could seriously impact on the risk of infection and indicate the need for further material development. These studies also suggest that inhibitors of S. epidermidis autolysin (AltE) may be useful coating agents to prevent bacterial adhesion to sutures.