“…The regulation of virulence determinant production in S. aureus involves several global regulatory loci; of these, sar and agr are the best characterized (15,45,54,56), though other regulators have been described (27,30). Inactivation of the sar or agr locus results in a pleiotropic decrease in levels of exoproteins and an overproduction of surface proteins, while mutants are less virulent than the parental strain in several animal models (1,15,17,18,39,45,54,56).…”