Mycobacterium marinum disease in Anne Arundel County: 1995 update.

A retrospective survey of 41 cases of culture-positive Mycobacterium marinum disease in Anne Arundel County, Maryland, showed that most infection was related to recreational exposure to the Chesapeake Bay and its tributaries. Three quarters of cases consisted of skin or joint/tendon infection of the upper extremity, particularly the hand. An empiric drug regimen for a granulomatous soft tissue infection in this context should include rifampin and ethambutol or cotrimoxazole (trimethoprim/sulfamethoxazole). A reactive tuberculin skin test in Anne Arundel County is more likely to represent M. marinum infection than tuberculous infection.