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Isoniazid Mono-Resistance — SCE Infectious Diseases MCQ

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ModerateTuberculosisIsoniazid Mono-ResistanceSCE Infectious Diseases

A 45-year-old man with HIV on ART develops Mycobacterium tuberculosis resistant to Isoniazid only (Isoniazid mono-resistance). How should the regimen be modified?

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Correct answer: D — Stop Isoniazid; continue Rifampicin plus Ethambutol; add a Fluoroquinolone (Moxifloxacin/Levofloxacin); extend total treatment to 9 months

Isoniazid mono-resistance requires regimen modification but is NOT MDR-TB (which requires Rifampicin resistance). Stop Isoniazid, continue Rifampicin and Ethambutol, and add a fluoroquinolone. Total duration extends to 9 months. This differs from MDR-TB management (BPaLM regimen).

Reference: NICE NG33 2016 – TB; WHO 2022 – Isoniazid-resistant TB