Mycobacterium avium complex (MAC) osteomyelitis and septic arthritis in an immunocompetent host

We describe a case of Mycobacterium avium complex (MAC) osteomyelitis and septic arthritis in an immunocompetent man. Infection was derived from a chainsaw injury sustained on the lateral aspect of the ankle 13 years earlier, and had spread through the bone, joint and soft tissue emerging at the medial aspect. This was successfully treated with surgical debridement, drainage, arthrodesis and 18 months of chemotherapy consisting of clarithromycin, rifampicin, ethambutol, and ciprofloxacin with an initial 2 weeks of amikacin. Infections with this organism are generally associated with immunocompromised states, particularly advanced AIDS. However, our patient illustrates that atypical mycobacterial infections must also be considered in immunocompetent patients who have a prolonged clinical course and an appropriate potential source of infection.