Clostridioides difficile infection — ABIM Board MCQ

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ModerateInfectious DiseaseClostridioides difficile infectionABIM Board

A 67-year-old woman develops frequent watery diarrhea after receiving clindamycin. Stool testing is positive for Clostridioides difficile toxin. Her leukocyte count is 18,000/µL and serum creatinine is 1.4 mg/dL. She is hemodynamically stable and has no ileus or toxic megacolon. Clindamycin is discontinued. This is her first episode of C. difficile infection. Which of the following is the most appropriate antimicrobial treatment?

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Correct answer: A — Oral fidaxomicin

This patient has an initial episode of severe but nonfulminant C. difficile infection: her leukocyte count is at least 15,000/µL, but she has no hypotension, ileus, or megacolon. Oral fidaxomicin is preferred for an initial CDI episode because it provides similar initial cure but a lower recurrence risk than oral vancomycin; oral vancomycin remains an acceptable alternative when fidaxomicin is unavailable. Intravenous vancomycin does not provide adequate intraluminal colonic therapy. Loperamide alone neither eradicates C. difficile nor treats toxin production. Metronidazole is no longer preferred and should not be selected for severe disease. Fecal microbiota transplantation is generally reserved for patients with multiple recurrences despite appropriate antibiotic treatment, not for a first episode.

Reference: Infectious Diseases Society of America and Society for Healthcare Epidemiology of America. Clinical Practice Guideline: 2021 Focused Update Guidelines on Management of Clostridioides difficile Infection in Adults, Recommendation I. 2021. https://www.idsociety.org/practice-guideline/clostridioides-difficile-2021-focused-update/