Equivalence of lauric acid and glycerol monolaurate as inhibitors of signal transduction in Staphylococcus aureus

Glycerol monolaurate (GML) inhibits the expression of virulence factors in Staphylococus aureus and the induction of vancomycin resistance in Enteroco ccus faecalis, presumably by blocking signal transduction. Although GML is rapidly hydrolyzed by bacteria, one of the products, lauric acid, has ident ical inhibitory activity and is metabolized much more slowly. At least four distinct GML-hydrolyzing activities are identified in S. aureus: the secre ted Geh lipase, residual supernatant activity in a geh-null mutant strain, a novel membrane-bound esterase, and a cytoplasmic activity.