Glycerol monolaurate inhibits the production of beta-lactamase, toxic shock toxin-1, and other staphylococcal exoproteins by interfering with signal transduction.

Glycerol monolaurate (GML) is a naturally occurring surfactant that is used widely as an emulsifier in the food and cosmetics industries and is generally regarded as lacking in important biological activities. The recent observation that it inhibits the production of staphylococcal toxic shock toxin-1 (P. M. Schlievert, J. R. Deringer, M. H. Kim, S. J. Projan, and R. P. Novick, Antimicrob. Agents Chemother. 36:626-631, 1992) is therefore rather surprising and raises the interesting question of how such a compound might interact with cells. In this report, we show that GML inhibits the synthesis of most staphylococcal toxins and other exoproteins and that it does so at the level of transcription. We find that GML blocks the induction but not the constitutive synthesis of beta-lactamase, suggesting that it acts by interfering with signal transduction.