A 23-year-old, ill-appearing woman comes to the emergency room with a fever. She notes the recent development of nausea, diarrhea, and a rash. Her last menstrual period began 3 days ago.Physical examination is remarkable for blood pressure of 90/45 mm Hg and hea rate of 120 beats per minute. A diffuse erythematous rash with areas of desquamation over the hands and feet is noted. Infection with which of the following agents is the most likely cause of these signs and symptoms?

This patient has toxic shock syndrome (TSS), a multisystem syndrome caused by a toxin (TSST-1) formed by ceain strains of S. aureus. TSS usually affects several organ systems (gastrointestinal, renal, hepatic, hematopoietic, musculoskeletal, pulmonary) and can result in death. TSS has historically been associated with the use of tampons in young women, but can also occur in other patient populations. Fever, hypotension, diarrhea, and diffuse rash with desquamation of the hands and feet are common symptoms. Management of shock, renal failure, and adult respiratory distress syndrome (ARDS) are a priority if these conditions are present, in addition to appropriate antibacterial treatment. C. perfringens causes gas gangrene, with necrosis of soft tissues, usually after a traumatic wound. It is also a cause of food poisoning. Although HIV-1 can cause many diverse findings and should never be immediately ruled out, the findings in this patient are most specific for TSS. Shigella dysenteriae is a cause of dysentery characterized by fever, abdominal cramps, and bloody diarrhea. Ref: Ray C.G., Ryan K.J. (2010). Chapter 24. Staphylococci. In C.G. Ray, K.J. Ryan (Eds), Sherris Medical Microbiology, 5e.