Nontuberculous mycobacterial skin infections: clinical and bacteriological studies.

OBJECTIVE

Nontuberculous mycobacterial (NTM) skin infections were analysed in terms of clinical manifestation in different species to provide clues for the clinical diagnosis and sensitivity patterns of these species were studied for planning appropriate therapy.

DESIGN

A retrospective study was performed in 123 suspected cases of NTM infections from January 1994 to December 2000. NTM infection was documented by culture result of the infected tissue obtained by skin biopsy. Drug susceptibility test was done as requested.

RESULT: Rapid growers (M. fortuitum-chelonae) were found in 26 cases (65%) and M. marinum was responsible for 12 cases (30%) and caused only localized skin lesions on arms or legs as indurated plaque, Disseminated skin infections manifested as multiple abscesses were found in 2 cases caused by M. avium in an HIV-infected male patient and mixed infection of M. szulgai and M. terrae in an immunocompetent female patient after a dental procedure. Both sexes were affected equally in overall number but male predominated in M. marinum infection and females predominated in rapid growers. All ages can be affected but most cases were middle aged. Scrofuloderma-like cervical lymphadenitis and cutaneous abscesses were the common manifestation of rapid grower infections. Hyperkeratotic verrucous plaques (tuberculosis verrucosa cutis-like) and sporotrichoid lesions were the common manifestations of M. marinum infection. M. marinum is sensitive to minocyclin, clarithromycin, amikacin, rifampicin and ethambutol and a good clinical response was obtained with doxycyclin 100 mg orally twice a day for 3 months. Clarithromycin and amikacin showed in vitro activity against the same strain of M. fortuitum but most strains of rapid growers resisted antituberculous drugs and also various antibiotics.

CONCLUSION

Clinical manifestations can be used as clues for diagnosis. Medical therapy is recommended for M. marinum infection and surgical treatment is recommended for rapid growers.