A master virulence regulator of S. aureus inactivated during carriage in man

It remains unclear how the bacterial populations which colonise many healthy humans occasionally give rise to severe disease. Staphylococcus aureus represents one such population. Here we describe mutations in invasive S. aureus which arose during human colonisation and inactivated rsp, a transcription factor. RNA-Seq was used to generate mRNA profiles of genes controlled by rsp. Overall design: mRNA samples were sequenced in duplicates from Staphylococcus aureus strains isolated from two patients with concomitant nasal carriage and bloodstream infection as well as from USA300 wild type and USA300 NE1304 NARSA (Network on Antimicrobial Resistance in Staphylococcus aureus) strain.