Fatal Panton-Valentine leukocidin-positive MSSA toxic shock syndrome: a call for rapid virulence detection and optimized antimicrobial therapy.

Background: Toxic shock syndrome (TSS) is a rare but potentially life-threatening toxin-mediated infection. Cases associated with Panton-Valentine leukocidin (PVL)-producing Objectives: This report aims to strengthen clinical understanding of TSS caused by methicillin-sensitive Methods: We present a case involving a 26-year-old female patient with MSSA isolated from multiple anatomical sites who initially received vancomycin before being diagnosed with PVL-positive MSSA-induced TSS. Therapeutic efficacy was evaluated by integrating her clinical course with contemporary evidence on the management of severe MSSA infections. In addition, treatment considerations for highly virulent MSSA infections with distinct clinical characteristics were examined. Results: The patient's clinical course enabled a comparative assessment of β-lactam antibiotics, such as cefazolin, versus glycopeptide agents, such as vancomycin, in the management of MSSA infections. Upon confirmation of MSSA, early transition to targeted therapy with cefazolin or anti-staphylococcal penicillins may be considered. In critically ill patients, early virulence gene testing is important for rapid identification of PVL-positive strains. Conclusions: PVL-positive MSSA may be associated with a fulminant, atypical toxic shock syndrome-like phenotype characterized by disseminated pustulosis and pancytopenia, which should raise immediate suspicion of a toxin-driven process. This case suggests that de-escalation from vancomycin to a β-lactam antibiotic upon MSSA confirmation may be a key therapeutic strategy. Increased vigilance, rapid virulence factor testing, and early aggressive management are important to improving outcomes.