Expression of the cloned toxic shock syndrome toxin 1 gene (tst) in vivo with a rabbit uterine model

Toxic shock syndrome (TSS) toxin 1 (TSST1) is produced by strains of Staphylococcus aureus associated with TSS. Purified TSST1 induces in rabbits a shock-like illness with many features similar to TSS in humans. These symptoms were also induced by TSST1-producing bacteria in diffusion chambers implanted in the rabbit uterus. Naturally occurring TSST1⁺ strains and a TSST1^- strain harboring a pE194-derived plasmid carrying the cloned TSST1 determinant tst gave the same symptoms. TSST1^- strains and a TSST1^- strain carrying a pE194-tst plasmid with a deletion of the tst gene had no effect in rabbits. The results with the plasmid-carrying TSST1⁺ and TSST1^- strains, which were isogenic apart from tst, show that the toxin is responsible for the illness in rabbits and suggest that it is a major factor in the pathogenesis of TSS.