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

Abstract Background The incidence of cutaneous nontuberculous mycobacteria (NTM) infections is increasing. These infections are a diagnostic and therapeutic challenge. Objective We aimed to investigate 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 initial evaluation and diagnosis was 12 weeks. Only 15% of AFB-positive cultures had a positive AFB smear, and those accompanied by skin biopsy had a positive Fite stain in only 43% of cases. Immunosuppressed patients were more likely to have a positive Fite stain. Treatment included surgery and multiple antibiotics. Immunosuppressed patients and M. 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. Conclusion Even with clinical suspicion, the diagnosis of NTM infection can be difficult. AFB smears and special stains are frequently negative. Antibiotic resistance is common. Multidrug treatment is often required, and surgical therapy may be needed.