STAPHYLOCOCCUS-AUREUS SMALL COLONY VARIANTS ARE INDUCED BY THE ENDOTHELIAL-CELL INTRACELLULAR MILIEU

Recent studies have reported that Staphylococcus aureus small colony v ariants (SCVs) can cause highly persistent infections in humans and in cultured endothelial cells. To understand the process by which SCVs o f S. aureus appear in subjects who have not received antibiotic treatm ent, bovine endothelial cells were coincubated with a wild S. aureus s train for 72 h in the presence of lysostaphin. Intracellular bacteria were harvested and screened for stable SCVs, Intracellular bacteria de veloped the SCV phenotype at a greater rate than control bacteria not exposed to endothelial cells: The intracellular induction rate was sim ilar to 10(-3) versus a spontaneous rate of <10(-7). This observation suggests that SCVs are induced by the intracellular milieu and suggest s a possible mechanism for the intriguing pathophysiology of tissue pe rsistence of staphylococci.