Effect of trace metals on the synthesis of toxic shock syndrome toxin 1

The effect of 10 trace metals on the production of toxic shock syndrome toxin 1 (TSST-1) was studied in a metal-deficient chemically defined medium (CDM) with toxic shock syndrome (TSS) and non-TSS strains of Staphylococcus aureus. When individual metals were tested, only Mg++ stimulated cell growth and TSST-1 production. TSST-1 yield was responsive to the concentration of Mg++ in the medium, with a maximal yield occurring at 0.1 mM. When other metals were studied in the presence of Mg++ with and without 1 mM ethylenediamine tetraacetic acid, it was found that Ca++, Co++, Cu++, Fe++, Mn++, molybdate-, Ni++, vanadate-, and Zn++ produced some stimulation of either cell growth or TSST-1 synthesis or both. The stimulating effect of Mg++ on TSST-1 synthesis was significantly enhanced by adding 0.3 mM Zn++ and 0.003 mM Fe++. TSST-1 production by 11 strains of S. aureus in CDM with optimal concentrations of trace metals was two to seven times greater than that produced in brain-heart infusion broth.