The control of death and lysis in staphylococcal biofilms: a coordination of physiological signals

The processes involved in the development of complex multicellular communities, including the programmed elimination of individual cells during the formation of specialized structures, exhibit fundamental similarities between prokaryotic and eukaryotic organisms. Mechanistic similarities may also exist at the molecular level, as bacterial proteins hypothesized to be related to the apoptosis regulator Bax/Bcl-2 family have been identified, fueling speculation about the existence of bacterial PCD. Here we review the regulatory networks controlling cell death and lysis in Staphylococcus aureus and examine the environmental parameters that might influence them during the development of a biofilm. We hypothesize that the heterogeneous environmental conditions found within a developing biofilm generate distinct physiological signals that coordinate the differential expression of cell death and lysis effectors.

► We discuss the roles of the Staphylococcus aureus cid and lrg operons in death and lysis during biofilm development.
► We describe the function of the S. aureus LytSR and CidR regulatory proteins in the control of cid and lrg expression.
► We hypothesize that the metabolic heterogeneity observed within the biofilm environment determines the differential expression of cid and lrg, which in turn, dictates which cells die and lyse.