Arthritis caused by Mycobacterium terrae in a patient with rheumatoid arthritis.

To date, few cases of human joint infection caused by the Mycobacterium terrae complex have been reported. Because M. terrae infection is a relatively uncommon problem, it can be mistaken for a noninfectious inflammatory joint condition. The most common presentation of M. terrae complex infection is tenosynovitis of the hand; infections in bones other than those of the hands are rarely reported. Here, we describe a patient with arthritis of the knee caused by M. terrae and review data from other cases reported in the medical literature.