Mycobacterium marinum — SCE Infectious Diseases MCQ

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HardTropical & Imported InfectionsMycobacterium marinumSCE Infectious Diseases

A fish-tank-associated hand ulcer has sporotrichoid spread and yields a slow-growing acid-fast bacillus only at 30°C. Which organism is most likely?

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Correct answer: D — Mycobacterium marinum

The best answer is “Mycobacterium marinum”. Aquatic exposure plus low-temperature acid-fast growth is characteristic of M. marinum; the alternatives differ in staining, culture or epidemiology. “Sporothrix schenckii” does not match the decisive clinical feature or cited guidance. “Nocardia brasiliensis” does not match the decisive clinical feature or cited guidance. “Mycobacterium ulcerans” does not match the decisive clinical feature or cited guidance. “Staphylococcus aureus” does not match the decisive clinical feature or cited guidance.

Reference: BTS non-tuberculous mycobacterial pulmonary-disease guideline: https://thorax.bmj.com/content/72/Suppl_2/ii1