Which organism is most commonly associated with toxic shock syndrome in menstruating women?

• A. Staphylococcus aureus
• B. Streptococcus pyogenes
• C. Staphylococcus epidermidis
• D. Escherichia coli

Answer: (A)

Toxic shock syndrome in menstruating women is most often caused by toxin-producing strains of Staphylococcus aureus. These bacteria can colonize the vagina or a tampon, especially with prolonged tampon use, and produce the toxin TSST-1. TSST-1 acts as a superantigen, triggering massive activation of T cells and a surge of inflammatory cytokines. That cytokine storm drives the fever, low blood pressure, rash, and potential organ involvement seen in TSS. While Streptococcus pyogenes can cause toxic shock–like illness, it is less commonly linked to menstrual TSS and is more often associated with nonmenstrual invasive infections. Staphylococcus epidermidis and Escherichia coli are not typical causes of menstrual TSS. So the best answer is Staphylococcus aureus.