Correct: E. Shigella can cause bloody diarrhea, and frequently affects young children and institutionalized patients. The pathogen is highly contagious, and is spread via fecal-oral transmission. The pathogen can lead to severe dehydration, and even cause febrile seizures in young patients. For clinically stable patients who can be managed via outpatient therapy, the optimal treatment is via PO TMP-SMX to decrease the risk of person-

to-person transmission. Choice A – Erythromycin is the first line treatment for bloody diarrhea caused by the pathogen campylobacter. However, for the purposes of decreasing transmissibility of suspected Shigella, TMP-SMX remains the mainstay of therapy. Choices B + C – Oral metronidazole and oral vancomycin can both be used in the treatment of Clostridium deficile. Alternatively, intravenous metronidazole can be given if the patient is unable to tolerate oral medications. Choice D – Oral quinolones can be used in cases of bloody diarrhea in which salmonella is the suspected pathogen. Salmonella is caused by the ingestion of contaminated poultry and/or eggs, and can ultimately lead to bacteremia in 5-10% of cases.