A hospitalised patient receiving broad-spectrum cephalosporins develops three unformed stools in 24 hours. Which statement about Clostridioides difficile testing is correct?
- A Test all hospitalised patients weekly regardless of symptoms
- B Culture for C. difficile is the gold standard used routinely for diagnosis
- C GDH plus toxin A/B immunoassay or NAAT for toxin genes is recommended only in patients with clinically significant diarrhoea on laxative-free status ✓
- D A positive toxin assay in an asymptomatic carrier requires treatment
Correct answer: C. GDH plus toxin A/B immunoassay or NAAT for toxin genes is recommended only in patients with clinically significant diarrhoea on laxative-free status
Explanation
Testing is indicated only for patients with unformed stools who are not on laxatives, using either a multistep algorithm (GDH antigen screen followed by toxin assay or NAAT) or NAAT alone. Asymptomatic colonisation is common in hospitals, and treating carriers offers no benefit, which eliminates option D. Routine surveillance testing of well patients is not recommended. Culture is slow, insensitive to toxigenic strain differences in practice, and reserved for epidemiology, not routine diagnosis.
Reference: Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 9th ed.
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