A Case of Mycobacterium Fortuitum Infection in the Left Thigh

In March 2024, our hospital confirmed a case of Mycobacterium fortuitum infection in the left thigh. In January 2024, the patient underwent buttock augmentation surgery at a private plastic surgery hospital. One month after the surgery, the patient sought medical attention at the plastic surgery hospital, due to pain in both legs while sitting. Upon examination, two subcutaneous masses were found in the left thigh, the tumors were painful to pressure, with obvious redness and swelling and elevated skin temperature; therefore, the patient was treated with intravenous infusion (cephalosporin drugs), but after one month of treatment, no significant improvement was observed. In order to seek additional diagnosis and treatment, the patient came to our hospital for treatment.

Clinical treatment of the left lower limb included wound debridement, abscess incision and drainage, and photodynamic therapy with 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT). During surgery, subcutaneous tough tissue was taken for pathogen examination, including acid fast staining, bacterial culture, and identification. Additional auxiliary examinations: urine routine, blood routine, coagulation function, liver function, kidney function, blood lipids, and blood sugar.

Bacterial acid-fast staining: positive. Bacterial Culture and Identification (MALDI-TOF MS): Mycobacterium fortuitum. Clinical treatment plan: clarithromycin 500 mg po bid, moxifloxacin 400 mg po qd, abscess incision and drainage, ALA-PDT. After 24 days of treatment, the patient's condition was good, the surgical incision healed well, there was no bleeding, exudation, or bruising, no redness, swelling, or tenderness, and the skin temperature was normal. The patient improved and was discharged.

This article reports a case of Mycobacterium fortuitum infection in the left thigh. The Mycobacterium fortuitum was quickly and accurately identified by MALDI-TOF MS, and reasonable treatment measures were adopted clinically. The patient improved and was discharged. I hope that in the future, this study can provide assistance for the clinical diagnosis and treatment of Mycobacterium fortuitum infections.