Toxic shock syndrome is primarily associated with which bacteria?

• A. Staphylococcus epidermidis
• B. Staphylococcus aureus
• C. Streptococcus pyogenes
• D. Streptococcus pneumoniae

Answer: (B)

Toxic shock syndrome is a toxin-mediated illness most commonly caused by Staphylococcus aureus producing the toxin TSST-1, a potent superantigen. This toxin bridges MHC class II molecules on antigen-presenting cells with T-cell receptors, triggering a massive, non-specific T-cell activation and a cytokine storm. The result is fever, low blood pressure, a diffuse red rash, and potential multi-organ dysfunction. While Streptococcus pyogenes can also cause a toxic shock–like syndrome via its own exotoxins, the classic and most typical association is with Staphylococcus aureus. The other organisms listed are not the usual culprits for TSS.