Osteomyelitis and tenosynovitis due to Mycobacterium marinum in a fish dealer.

Osteomyelitis caused by nontuberculous mycobacteria is rarely reported. We describe a case of tenosynovitis and osteomyelitis of the right middle finger and metacarpal bone caused by Mycobacterium marinum in a fish dealer. This 52-year-old woman suffered progressive pain, numbness, tenderness, and erythematous swelling of the right middle finger over a 2-month period. A radiograph of the right hand disclosed osteolytic lesions at the third metacarpal bone and the third proximal phalanx. She was treated successfully with repeated surgical debridement and antimicrobial agents, including clarithromycin, ethambutol, rifampin, and doxycycline for 1 month, followed by ethambutol and clarithromycin. Pathologic examination of the debrided tissue disclosed epithelioid granuloma, caseous necrosis, and numerous acid-fast bacilli, which were later identified as M. marinum using conventional biochemical tests and by the characteristic gas-liquid chromatogram of esterified cellular fatty acid. The wound healed completely after 7 months of treatment. The patient is still under treatment, and clarithromycin and ethambutol will be given for a total of 18 months.