Melioidosis treatment — DTM&H MCQ

Correct answer: D — Eradication therapy with oral co-trimoxazole

The correct answer is D, eradication therapy with oral co-trimoxazole. Melioidosis (Burkholderia pseudomallei infection) is treated in two mandatory phases: an intensive intravenous phase (ceftazidime or meropenem) to control the acute sepsis, followed by a prolonged oral eradication phase, for which co-trimoxazole is the recommended agent. This second phase, typically lasting three to six months (longer with osteomyelitis, neurological or prostatic disease), is essential because B. pseudomallei is a facultative intracellular organism capable of persisting in tissues such as the prostate, and premature cessation carries a substantial risk of clinical relapse or recrudescence. This patient's prostatic abscess is a recognised site of latent organism persistence, reinforcing the need for a full eradication course rather than a short antibiotic run. Why the other options are wrong: A. Isoniazid preventive therapy: this is used for latent tuberculosis, an unrelated organism and disease process, with no role in melioidosis management. B. Praziquantel after discharge: praziquantel treats trematode and cestode infections (e.g. schistosomiasis), not a Gram-negative bacterial infection like melioidosis. E. Stop antibiotics once fever resolves: defervescence reflects control of the acute bacteraemic illness but does not indicate eradication of intracellular organisms; stopping here is the classic error leading to relapse, particularly with deep-seated foci such as prostatic abscess. C. Single-dose azithromycin: azithromycin has no established efficacy against B. pseudomallei and single-dose regimens are wholly inadequate for a pathogen requiring months of eradication therapy. Key point: after intravenous induction therapy for melioidosis, a prolonged oral eradication course (co-trimoxazole) is mandatory to prevent relapse from persistent intracellular organisms, especially with deep foci like prostatic abscess.

Reference: Annals of Clinical Microbiology and Antimicrobials (2023), 'Efficacy and safety of co-trimoxazole in eradication phase of melioidosis: systematic review', https://ann-clinmicrob.biomedcentral.com/articles/10.1186/s12941-023-00620-z; BNF (co-trimoxazole, severe infections)