Staphylococcus aureus small colony variants (SCVs), which are characterized by slow growth and a range of morphological and metabolic changes including altered antibiotic resistance profiles, have been studied for several decades. This Closeup highlights findings described in this issue of EMBO Molecular Medicine by Tuchscherr et al (2011), who present strong evidence that SCVs can arise in chronic infection models when S. aureus is internalized in non-professional phagocytes and survives intracellularly. As the intracellular residency time increases, the proportion of SCVs grows and the host cell inflammatory response diminishes. The study suggests that this mode of phenotype switching is an essential feature of the S. aureus infection process and can explain an underlying cause of chronic and relapsing infections.
See related article in EMBO Mol Med (Tuchscherr et al (2011) EMBO Mol Med 3: 129-141)