Fish tank granuloma in Chinese restaurant chefs in Victoria – an occupational hazard

Fisk tank granuloma is an uncommon cutaneous infection caused by Mycobacterium marinum. We report two separate cases of fish tank granuloma in Chinese restaurant chefs. The two patients had migrated to Australia from Hong Kong and Macau at least 3 years prior and worked in separate restaurants in Melbourne. Both presented with chronic non-healing lesions on the upper limbs, which developed after antecedent minor trauma to the area.
Initial skin biopsies were negative for acid-fast bacilli in both patients, and the causative organism, Mycobaterium marinum, was cultured only upon repeat testing. QuantiFERON testing was also positive in both patients. Definitive diagnosis was reached over a year after initial onset of symptoms and they were treated with combination antibiotic therapy to good clinical effect.
In this report, we identify Chinese restaurant workers as a uniquely at-risk group for Mycobacterium marinum infection in the Australian context, and highlight the need for a strong index of suspicion, as multiple biopsies and repeated testing may be necessary to confirm the diagnosis.

Miss Esther Sim