TSST

TSST commonly refers to toxic shock syndrome toxin-1 (TSST-1), a potent superantigen produced by the bacterium Staphylococcus aureus. TSST-1 is one of several staphylococcal toxins that can trigger systemic illness. It was first associated with toxic shock syndrome in the late 1970s and 1980s, notably in cases linked to high-absorbency tampons, though nonmenstrual cases occur as well.

Mechanism and effects: TSST-1 binds to major histocompatibility complex class II molecules on antigen-presenting cells and to the variable region of the beta chain of T-cell receptors. This cross-links immune cells outside their normal antigen-specific contexts, causing widespread T-cell activation and massive cytokine release (including IL-1, IL-2, TNF-α, and interferon-γ). The resulting cytokine storm leads to fever, hypotension, rash, desquamation, and potential multiorgan dysfunction.

Clinical presentation and diagnosis: Toxic shock syndrome presents with abrupt fever, low blood pressure, a diffuse erythroderma, and often multiorgan involvement such as vomiting, diarrhea, renal dysfunction, or hepatic abnormalities. Diagnosis is clinical, supported by laboratory evidence of infection with S. aureus and, when available, detection of TSST-1 toxin or the tst gene in the responsible strain. Blood cultures are often negative or show nonbacteremic infection.

Treatment and prognosis: Management requires rapid supportive care (fluids, vasopressors as needed) and antimicrobial therapy targeting S. aureus (typically nafcillin or oxacillin for methicillin-susceptible strains, or vancomycin/linezolid for MRSA). Adjunctive clindamycin can help suppress toxin production. Intravenous immunoglobulin has been used in severe cases. With prompt treatment, outcomes improve substantially.

Genetics and epidemiology: The tst gene encoding TSST-1 is located on a Staphylococcus aureus pathogenicity island and can be coexpressed with other toxin genes. Public health measures focus on hygiene and safe tampon use to reduce menstrual cases, while awareness of nonmenstrual toxemia remains important.