Abstract: The data of nine patients (7 males and 2 females) with fish stabbing granuloma from August 2020 to April 2021 were analyzed retrospectively. The patients aged from 21 to 63 years old. Three patients presented with localized plaques and six presented with dark red subcutaneous nodules that along lymphatic vessels. PPD test was performed in all 9 patients and 7 were positive. Of 5 patients who underwent T-spot test, 3 were positive. Of 9 patients, 2 cases were both positive of PPD and T-spot test, 2 were positive of PPD test but negative of T-spot test, 1 was negative of PPD but positive of T-spot test. The coincidence rate of strain identification was 100% by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) and 16s ribosomal RNA gene sequencing. The biopsy of lesions showed infectious granulomas. The therapy methods included oral clarithromycin, clarithromycin, rifampicin, isoniazid, topical ALA-PDT and hot pack. Of 9 patients, 5 were cured and 4 significantly improved.

Key words: Mycobacterium marinum, infectious granuloma, swimming pool granuloma, fish stabbing granuloma