To confirm the higher activity of the SaeRS TCS in the wild type mice, we collected S. aureus from peritoneal fluid at 12 h post infection; then the transcription of the known sae target genes (saeP, coa, hla, fnbA, sak, and lukS-PV) and two non-sae target genes (psmα and spa) were analyzed. The gene discussed is PLK4; the disease is infection.