Table 1.

Activities of the PSM-mec peptide and the psm-mec srRNA.

Virulence determinant within the psm-mec locus	Known in vitro activities in S. aureus
PSM-mec peptide	FPR2-mediated pro-inflammatory activity at nM concentrations:    • Increased CD11b expression    • Increased gp91phox expression    • Increased IL-8 expression    • Increased calcium flux    • Increased chemotaxis
	Receptor-independent cytolytic activity at μM concentrations toward:    • Erythrocytes    • Neutrophils
	Peptide expression decreases oxacillin resistancea
psm-mec srRNA	Represses AgrA activity through direct interaction    • Decreased PSM productionb    • Enhanced biofilm formation and aggregationb    • Suppresses colony spreading    • Up-regulates SpA expressionb

^aOnly tested in one background strain.

^bStrain-specific phenotype.