The ROSA-like prophage colonizing Staphylococcus aureus promotes intracellular survival, biofilm formation and virulence in a chronic wound environment.

The transition from colonization to invasion is critical in diabetic foot ulcer (DFU). S. aureus can colonize DFU, or invade the underlying tissues, causing serious infections. The ROSA-like prophage has previously been implicated in strain colonization characteristics of S. aureus isolates in uninfected ulcers. Here, we investigated this prophage in the S. aureus colonizing strain using an in vitro chronic wound medium (CWM) mimicking the chronic wound environment. CWM reduced bacterial growth and increased biofilm formation and virulence in a zebrafish model. Moreover, the ROSA-like prophage promoted intracellular survival of S. aureus colonizing strain in macrophages, keratinocytes and osteoblasts.