Characteristics of skin and soft tissue infection caused by non-tuberculous mycobacteria in Taiwan.

SETTING: A medical centre in Taipei, Taiwan.

OBJECTIVE: To investigate the clinicopathological and microbiological correlates of skin and soft tissue infection (SSTI) due to non-tuberculous mycobacteria (NTM).

DESIGN: Patients with NTM SSTI identified from 1999 to 2009 were included. Histological sections of the skin biopsy specimens from these patients were reassessed.

RESULTS: Among 58 patients with NTM SSTI, the most commonly isolated NTM were rapidly growing mycobacteria (RGM; n = 30), Mycobacterium marinum (n = 17) and M. avium complex (MAC) (n = 4). Twenty-nine (50%) of the NTM SSTI involved deep soft tissue; these progressed to local tenosynovitis in 20 patients. All of the cutaneous lesions infected with M. marinum occurred on the upper extremities; in 9 patients the skin eruptions developed after injury in an aquatic environment. Skin lesions with RGM infection usually occurred on the lower extremities, and in 6 patients the infection developed from wounds caused by medical procedures. Granulomatous inflammation with fibrinoid necrosis was present in 47% of lesions in patients with M. marinum infection and suppurative granulomatous inflammation was noted in 45% of patients with RGM infection.

CONCLUSIONS: Identification of a close clinicopathological correlate is useful for dermatologists and pathologists in the early diagnosis and treatment of NTM SSTI.