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Relapsing Clostridioides difficile infection — MSRA MCQ

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ModerateInfectious DiseasesRelapsing Clostridioides difficile infectionMSRA

A 74-year-old woman is reviewed urgently in general practice after a stool sample sent yesterday returns positive for Clostridioides difficile toxin. She has passed 6 watery stools in the past 24 hours and has mild lower abdominal cramping but no vomiting, fever, hypotension, abdominal distension or confusion. She is drinking adequately. Her observations are normal and there are no features suggesting life-threatening infection. Ten weeks ago, she completed a 10-day course of oral vancomycin for a toxin-positive first episode of C. difficile infection. Her diarrhoea resolved completely within 4 days of treatment and did not recur until yesterday. She has not received systemic antibiotics since. She can take oral medication and has no relevant drug allergies. Following discussion with the local microbiology service, which treatment should be prescribed now?

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Correct answer: A — Oral fidaxomicin 200 mg twice daily for 10 days

This is a further episode of toxin-positive C. difficile infection occurring within 12 weeks of symptom resolution from the previous episode. NICE defines this timing as a relapse and recommends fidaxomicin 200 mg orally twice daily for 10 days. The absence of hypotension, ileus, marked systemic illness or abdominal distension means there is no indication for life-threatening-infection regimens or urgent surgical assessment. Vancomycin 125 mg four times daily for 10 days is first-line for an initial episode and is an option for a further episode occurring more than 12 weeks after symptom resolution, which NICE defines as recurrence rather than relapse. A vancomycin taper-and-pulse regimen is not recommended by NICE for routine management because the supporting evidence was limited to studies involving co-administration of faecal microbiota transplant. Metronidazole is not a recommended standard oral regimen for a further episode in this setting. Although an extended-pulsed fidaxomicin regimen has been studied, NICE does not recommend it over the licensed 10-day regimen because benefit and cost-effectiveness remain uncertain. Review of potentially contributory medicines, including proton-pump inhibitors, laxatives and medicines that increase risk during dehydration, should also occur.

Reference: Clostridioides difficile infection: antimicrobial prescribing (NG199) — Recommendations (2025) — https://www.nice.org.uk/guidance/ng199/chapter/Recommendations Clostridioides difficile infection: antimicrobial prescribing (NG199) — Rationale and impact (2025) — https://www.nice.org.uk/guidance/NG199/chapter/rationale-and-impact Clostridioides difficile infection: antimicrobial prescribing (NG199) — Recommendations (2025) — https://www.nice.org.uk/guidance/ng199/chapter/Recommendations