Atypical Mycobacterium infections of the upper extremity

Thirty-three patients with culture-positive atypical Mycobacterium infections of the upper extremity underwent surgical debridement and antimicrobial therapy. The causative atypical organism was M. marinum in 12 cases, M. avium-intracellulare in 7, M. terrae in 4, M. chelonei in 4, M. kansasii in 3, M. fortuitum in 2, and M. ulcerans in 1. The tenosynovium was the most common location of infection (14 patients). The average follow-up period was 36 months. Duration of antimicrobial therapy averaged 10 months. The average delay between onset of symptoms to correct diagnosis was 1 year. There were seven superficial infections; six were caused by M. marinum and one was caused by M. ulcerans. All of these cutaneous infections resolved following incisional or excisional biopsy and pharmacologic therapy. The remaining 26 infections involved the deeper tissues, and M. avium-intracellulare was the most common organism. The immune status of the host was an overwhelming predictor of eventual outcome. In the 15 patients with competent immune systems, resolution occurred in 13. However, in the immunocompromised patient population, only 4 of the 10 had resolution of deep infection at time of the follow-up evaluation.