The
coagulase-negative staphylococci and, in particular, Staphylococcus epidermidis, have emerged as major nosocomial pathogens associated with
infections of implanted medical devices. These organisms, which are among the most prevalent bacteria of the human skin and mucous membrane microflora, present unique problems in the diagnosis and treatment of
infections involving biofilm formation on implanted
biomaterials. Epidemiological data that address whether invasive S. epidermidis strains can be traced to commensal organisms or an endemic occurrence of distinct strains with enhanced virulence have important implications for the implementation of appropriate infection control measures. An extracellular
polysaccharide adhesin represents a key virulence determinant in S. epidermidis and is required for biofilm formation. Production of this adhesin, which is encoded by the ica operon, is subject to phase variable regulation (ON <---> OFF switching). Recent advances in understanding the molecular events controlling
polysaccharide adhesin synthesis and the potential clinical implications of its phase variable regulation are outlined. Further research in this area may contribute to the development of novel strategies for therapeutic intervention. Finally, in addition to
antibiotic prophylaxis, preventive strategies to control S. epidermidis medical device-related
infections are focusing on the development of improved
biomaterials and physical electrical barriers to impede bacterial colonisation.