American Board of Family Medicine (ABFM) Practice Exam 2026 - Free ABFM Practice Questions and Study Guide

The recommended treatment for a severe Clostridium difficile infection is oral vancomycin. This is due to its high efficacy in targeting the C. difficile bacteria, especially in severe cases where the infection can lead to significant morbidity. Oral vancomycin is preferred over other treatments because it provides adequate local concentration in the gastrointestinal tract, where the fecal bacteria reside, allowing it to effectively eradicate the pathogen.

In cases of severe infection, the dosing and duration of treatment are essential in ensuring resolution of symptoms and preventing recurrence. Although oral metronidazole was previously used, current guidelines favor oral vancomycin for severe infections due to its superior effectiveness and lower risk of treatment failure. Intravenous antibiotics do not provide sufficient concentration in the gut to treat this specific infection effectively, and probiotic supplements, while sometimes suggested for prevention or as adjunct therapy, are not a recommended primary treatment.