Mycobacterium fortuitum: an unsuspected cause of synovitis and osteomyelitis.

Two men with progressive synovitis and osteomyelitis of the wrist were found to have infection with Mycobacterium fortuitum. Immunological defects were demonstrated in both cases in association with renal failure and renal transplantation respectively. Failure of appropriate antibiotic therapy to eradicate infection necessitated amputation in one case. M. fortuitum is frequently sensitive to only amikacin or kanamycin. Treatment with amikacin alone was unsuccessful. This organism is widespread in the environment and may need to be considered in undiagnosed chronic infection in the immunologically suspectible host, as it poses unusual problems in diagnosis and therapy.