Mycobacterium szulgai: an unusual pathogen.

Mycobacterium szulgai is an unusual pathogen that accounts for less than 1% of all cases of non-tuberculosis mycobacterial infection. Infections with this organism usually involve the lung but may involve soft tissues. Although similar to tuberculosis in its clinical presentation, infection due to M. szulgai requires different management, and it is therefore important to distinguish disease caused by M. szulgai from that caused by M. tuberculosis. Isolation of M. szulgai implies the presence of clinical disease, and when the organism is identified, treatment based on sensitivity testing should be initiated. Although no standard recommendations for treatment exist, most infections due to M. szulgai have been treated with combined high doses of isoniazid, ethambutol, and rifampin for 18-24 months. M. szulgai has been isolated worldwide; the first case of infection reported from Canada is described, and the clinical presentation, microbiologic diagnosis, and therapeutic management of M. szulgai infections are reviewed.