Mycobacterium marinum arthritis.

Mycobacterium marinum is an atypical acid-fast organism that is rarely associated with septic arthritis. Most often this is seen in patients with monarticular synovitis of the hands or wrists, especially in association with a history of periarticular trauma or exposure to marine environments. From tissue obtained by aspiration or synovectomy, Mycobacterium marinum can be identified by Ziehl-Nielson stain and has optimal growth in Lowenstein-Jenson medium. Therapy should consist of at least two antimycobacterial agents for a minimum 6 months. Surgical debridement also may be beneficial. The clinician must have a high index of suspicion that exposure to Mycobacterium marinum has occurred so appropriate stains and cultures can be obtained and antimycobacterial therapy initiated.