Non-tuberculous mycobacterial infections of the skin: a retrospective study of 29 cases.

The incidence of infections caused by non-tuberculous mycobacteria has increased in recent years, due to a rise in dermatological procedures and a greater prevalence of immunosuppression in the general population. This study investigated the clinical and microbiological findings of non-tuberculous mycobacterial skin infections. The study population included 29 patients from whom non-tuberculous mycobacteria were cultured after isolation from skin biopsy materials, cutaneous abscesses or exudates. Clinical, microbiological and epidemiological data were collected from each patient. Eight patients were immunocompromised while 21 were not. Precipitating factors such as acupuncture, filler injection, surgical procedures and other traumatic events preceded infection in 13 (including 11 normal hosts and two immunocompromised hosts) of the 29 patients. Multiple skin lesions were present in eight patients (including three normal hosts and five immunocompromised hosts). In eight patients (including four immunocompromised hosts), symptoms were accompanied by tenosynovitis, osteomyelitis and myositis. Mycobacterium abscessus was isolated from nine patients, Mycobacterium fortuitum was isolated from nine patients, Mycobacterium chelonae was isolated from six patients, Mycobacterium marinum was isolated from two patients, a Mycobacterium avium complex member was isolated from two patients, and Mycobacterium haemophilum was isolated from one patient. Ten of the 24 cases caused by rapidly growing organisms (i.e. M. chelonae, M. abscessus and M. fortuitum groups) were precipitated by skin injuries such as acupuncture, filler infection and other medical procedures. Increases in skin medical procedures, including both acupuncture and esthetic interventions, explain the increasing incidence of these organisms. Immunocompromised patients tended to develop multiple skin lesions and deep tissue infections.