Thymidine-dependent Staphylococcus aureus small-colony variants: human pathogens that are relevant not only in cases of cystic fibrosis lung disease.

We report the isolation of thymidine-dependent small-colony variants (TD-SCVs) of Staphylococcus aureus from unusual infection sites of patients with chronic soft tissue infection, tympanitis, bronchitis, peritonitis, and septicemia. Furthermore, we provide evidence that the essential growth factor for TD-SCVs, i.e., thymidine, and its metabolite dTMP are present in various human specimens.