Abstract: Mycobacterium fortuitum is an opportunistic pathogen, and iatrogenic infections caused by this bacterium have been on the rise in recent years. The patient in this study presented with subcutaneous induration and tenderness at abdominal injection sites for 13 days. She reported receiving abdominal subcutaneous injections of a “fat-dissolving injection” for weight loss at a beauty salon 2 months prior to the onset of symptoms. The pathogen was identified as Mycobacterium fortuitum using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, gene chip, and molecular sequencing. The patient was allergic to rifampicin and ethambutol, and ototoxicity occurred during amikacin treatment. Finally, oral moxifloxacin combined with clarithromycin plus surgical debridement was adopted, and the patient recovered after 6 months of treatment with no recurrence during 3 years of follow-up.

Key words: cutaneous soft tissue infection, Mycobacterium fortuitum, fat-dissolving injection