Occupational Mycobacterium marinum Infection Following Fish and Aquaculture Exposure: A Case Report and Literature Review.

OBJECTIVE: To describe the clinical characteristics, and treatment duration and outcomes associated with different therapeutic regimens for Mycobacterium marinum infection. METHODS: We report a case caused by Mycobacterium marinum, presenting with erythema and erosions on the left forearm and left fingers, which was confirmed by histopathological examination and polymerase chain reaction (PCR)-based gene sequencing. A narrative literature review was also conducted to summarize reported antimicrobial regimens, treatment durations, and clinical outcomes. RESULTS: In the present case, the diagnosis was supported by positive acid-fast staining and PCR-based gene sequencing of the lesional specimen. No culture-positive isolate was obtained. The patient was treated with a combination of clarithromycin and rifampicin for four months, resulting in marked regression of skin lesions. The literature review indicated that monotherapy is mainly applied in patients with localized and superficial disease, with a typical treatment duration of 4-6 months. Dual-drug regimens represent the most commonly used therapeutic approach, with treatment courses generally lasting 3-5 months. Triple-drug therapy is primarily reserved for disseminated or deep-seated infections, with treatment durations ranging from 2 to more than 8 months. CONCLUSION: Mycobacterium marinum infection is prone to misdiagnosis due to its nonspecific clinical presentation. Definitive diagnosis relies on histopathological examination and molecular biological techniques. Treatment strategies should be individualized according to the extent and severity of lesions. Standardized combination therapy administered for an adequate duration is associated with favorable clinical outcomes.