Effect of dilution rate and Mg2+ limitation on toxic shock syndrome toxin-1 production by Staphylococcus aureus grown in defined continuous culture.

A toxic shock syndrome isolate of Staphylococcus aureus was grown in a chemostat, in a defined synthetic medium of six amino acids, glucose, two vitamins and salts. Steady states were achieved under limiting and replete Mg2+ conditions and at a range of relative specific growth rates. The biomass and toxic shock syndrome toxin-1 (TSST-1) were estimated at each condition. Under Mg2+ limitation the biomass and TSST-1 production rates were reduced compared to Mg2+ replete conditions. Optimal TSST-1 production occurred at 0.81 relative specific growth rate.