A Case Report of Pediatric Subcutaneous Abscess with Mycobacterium mageritense Infection

Soft-tissue infection with Mycobacterium mageritense is uncommon. We present the case of a 5-year-old girl who developed soft-tissue infection with M. mageritense in a subcutaneous abscess in her right ankle. She had a history of acute encephalopathy and adrenal insufficiency and was hospitalized for acute pancreatitis. During hospitalization, she developed fever and tachycardia. A blood culture was positive for gram-positive bacilli. Initially, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) reported a different organism, but a repeat test identified M. mageritense. One month after the positive blood culture, redness and swelling appeared in her right ankle. Drainage from the subcutaneous abscess again grew M. mageritense, which was also confirmed by sequencing of housekeeping genes. Based on a sensitivity test, she was treated with tosufloxacin and linezolid. After starting treatment, local inflammatory findings gradually improved. Antibiotic treatment was completed in 6 months, and she has experienced no relapse in the 8 months since the completion of therapy. This first case report of pediatric M. mageritense infection highlights an important potential pitfall of MALDI-TOF MS. We also report that the choice of antimicrobials for treatment of M. mageritense may be more limited in children than that for adults.