A previously healthy fifty-seven-year-old woman presented with an acute atypical mycobacterial infection of the first metatarsal bone of the left foot. Despite antimicrobial treatment, the infection was not controlled. First-ray amputation was performed, and antimicrobial treatment was continued for a total of six months. The patient was fitted with an orthotic (insole) and followed for eighteen months; there was no recurrence of infection.
To the best of our knowledge, this is the first case report describing Mycobacterium chelonae osteomyelitis of the first metatarsal ray in an immunocompetent individual. This diagnosis should be considered in patients with osteomyelitis that persists despite the use of broad-spectrum antibiotics, even in healthy individuals.