Current concepts in biofilm formation of Staphylococcus epidermidis.

Staphylococcus epidermidis is a highly significant nosocomial pathogen mediating infections primarily associated with indwelling biomaterials (e.g., catheters and prostheses). In contrast to Staphylococcus aureus, virulence properties associated with S. epidermidis are few and biofilm formation is the defining virulence factor associated with disease, as demonstrated by animal models of biomaterial-related infections. However, other virulence factors, such as phenol-soluble modulins and poly-gamma-DL-glutamic acid, have been recently recognized that thwart innate immune system mechanisms. Formation of S. epidermidis biofilm is typically considered a four-step process consisting of adherence, accumulation, maturation and dispersal. This article will discuss recent advances in the study of these four steps, including accumulation, which can be either polysaccharide or protein mediated. It is hypothesized that studies focused on understanding the biological function of each step in staphylococcal biofilm formation will yield new treatment modalities to treat these recalcitrant infections.