Transcriptional variation of regulatory and virulence genes due to different media in Staphylococcus aureus.

The pathogenesis of staphylococcal infections is a multifactorial process that depends on expression of different virulence factors. Expression of these factors is controlled by multiple regulatory systems in conjunction with environmental signals. Most of the genetic studies in Staphylococcus aureus have been performed using different growth media, therefore, we examined the effects of different growth media on transcription of the selective target (e.g., hla, hlb, spa, sspA) and regulatory (e.g., agr, sarA family) genes. The results from this study suggest that different growth media have substantial effect on transcription of various genes being analyzed. Interestingly, when compared with the wild-type, the isogenic sarA mutant showed a media-dependent distinct regulatory effect on expression of the target genes.