Mycobacterium marinum infection following contact with reptiles: vivarium granuloma

Summary A 19-year-old man presented with a 1.5-cm nodule on the first dorsal metacarpal ray. The patient denied having contact with fish tanks or fish, but recalled handling many reptiles without gloves in the vivarium where he worked. A culture of a skin biopsy specimen yielded Mycobacterium marinum . The clinical outcome was favourable after a 2-week course of intramuscular gentamicin (180mg daily) combined with a 6-week course of oral clarithromycin (500mg twice a day). Doctors should be aware that vivariums, in addition to fish tanks, can be sources of M. marinum exposure.