Epidemiology, risk factors, and outcomes of adult cutaneous non-tuberculous mycobacterial infection over a 10-year period in Singapore

BackgroundUnfamiliarity with the presentation, diagnostic process, and treatment of cutaneous non-tuberculous mycobacterium (NTM) infection leads to poorer outcomes. We describe our experience with managing cutaneous NTM infection in a regional hospital in Singapore from 2005 to 2014. MethodsAdult patients with cutaneous NTM infections were identified through positive skin tissue cultures in this retrospective case series. We excluded patients younger than 21years of age, patients whose care was transferred to another hospital, and patients with catheter-related infections. Data including demographic variables, as well as disease and treatment outcomes, were collected. We compared the data between patients with and without risk factors for immunosuppression to look for any significant difference. ResultsFifty-eight cases were reviewed. Mycobacterium abscessus was the commonest organism isolated (51.7%), and abscesses or inflamed cysts were the most common presentation. Nineteen specimens (57.6%) showed suppurative or necrotizing granulomatous dermatitis on biopsy and acid-fast bacilli were identified in 2 of 21 histologic specimens (9.5%) stained for mycobacterium. Treatment included systemic antibiotics, surgery, or both. In total, 33 cases had clinical resolution while 25 cases were lost to follow-up. Our study was limited by the under-reporting of cases, bias due to data from a single center, and high dropout rates, thereby precluding a detailed assessment of treatment outcomes. ConclusionsA high index of suspicion is required to diagnose cutaneous NTM infection. Education of both patients and physicians will help to raise the level of awareness and reduce treatment delays.