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Culture-Positive 2-Month TB — SCE Infectious Diseases MCQ

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ModerateTuberculosisCulture-Positive 2-Month TBSCE Infectious Diseases

A 45-year-old man with TB completes 2 months of intensive phase (RHZE) and is about to start the continuation phase (RH for 4 months). His 2-month sputum culture is still POSITIVE for M. tuberculosis. Sensitivities confirm pan-susceptible TB. What is the management?

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Correct answer: E — Extend the continuation phase by 3 months (total 9 months instead of 6) — culture positivity at 2 months is a risk factor for relapse and warrants treatment extension

Culture positivity at 2 months of TB treatment (in pan-susceptible TB with confirmed adherence) is a risk factor for relapse. NICE NG33 and ATS/IDSA guidelines recommend extending the continuation phase by 3 months (total treatment 9 months) for patients with: positive 2-month culture, cavitary disease on initial CXR, or both. The extended course reduces relapse rates from ~5% to ~2%. There is no need to change the drug regimen if susceptibility is confirmed — this is NOT drug resistance. Adherence support (DOT if not already in place) should be reinforced.

Reference: NICE NG33 2016 – TB; ATS/IDSA 2003 – TB treatment; WHO 2022