Cutaneous nontuberculous mycobacteria infections: A retrospective case series of 78 patients from the Texas Gulf Coast region

Background: The incidence of cutaneous nontuberculous mycobacteria (NTM) infections is increasing. These infections are a diagnostic and therapeutic challenge. Objective: We investigated the clinical features, diagnosis, and management of cutaneous NTM infections. Methods: A retrospective case series studied 78 patients from a Gulf Coast tertiary referral center diagnosed with cutaneous NTM infection by culture or stain of a skin biopsy specimen. Results: A history of trauma, procedure, or environmental exposure was common. The mean time between the initial evaluation and diagnosis was 12 weeks. Only 15% of acid-fast bacillus-positive cultures had a positive acid-fast bacillus smear, and only 43% of those accompanied by skin biopsy specimen had a positive Fite stain. Immunosuppressed patients were more likely to have a positive Fite stain. Treatment included surgery and multiple antibiotics. Immunosuppressed patients and Mycobacterium abscessus group infections were more likely to have persistent disease. Limitations: M chelonae and M abscessus isolates were indistinguishable and therefore were reported together. Five cases were not confirmed by culture. Conclusions: Even with clinical suspicion, the diagnosis of NTM infection can be difficult. Results of acid-fast bacillus smears and special stains are frequently negative. Antibiotic resistance is common. Multidrug treatment is often required, and surgical therapy may be needed.