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Clostridioides difficile Infection — RACP Adult Medicine MCQ

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ModerateInfectious DiseasesClostridioides difficile InfectionRACP Adult Medicine

A 72-year-old man in hospital develops profuse watery diarrhoea on day 8 of IV piperacillin-tazobactam for hospital-acquired pneumonia. He is febrile (38.5°C) and has lower abdominal tenderness. WCC is 22 × 10⁹/L. Stool PCR for Clostridioides difficile toxin is positive. What is the most appropriate treatment for a first episode of non-severe C. difficile infection?

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Correct answer: B — Oral fidaxomicin 200 mg BD for 10 days

Per updated guidelines, oral fidaxomicin is now preferred over oral vancomycin for initial episodes of C. difficile infection due to lower recurrence rates (EXTEND trial). However, where fidaxomicin is not available, oral vancomycin remains appropriate. The offending antibiotic should be ceased or narrowed where possible.

Reference: eTG Antibiotic – 2025 – C. difficile; IDSA/SHEA 2021 CDI Guidelines