MYCOBACTERIUM-XENOPI IN HIV-INFECTED PATIENTS - AN EMERGING PATHOGEN

Background: Mycobacterium xenopi is associated with pulmonary disease in patients with loss of local or general host defence. Objectives: To determine the occurrence of M, xenopi in our hospital during 1987-199 2 and 1993-1996, as well as the association of M, xenopi with HIV infe ction in 1993-1996; to evaluate the clinical significance of M. xenopi in HIV-seropositive patients. Design: Retrospective review of charts and classification of patients based on earlier definitions derived fr om the American Thoracic Society. Setting: Tertiary hospital. Patients : Patients with a positive isolate of M. xenopi from January 1987 unti l December 1996. Main outcome measures: During 1993-1996, a significan t increase in the number of patients with M. xenopi was found compared with 1987-1992. OF 25 patients, 22 were HIV-seropositive. Results: Th e HIV-seropositive patients were classified as having definite (n = 5) , probable (n = 9) and unlikely disease (n = 8) due to M. xenopi. Symp toms, median CD4 cell count, treatment and outcome did not differ betw een these groups. Conclusions: M. xenopi is an emerging pathogen, espe cially in HIV-infected patients. The criteria of the American Thoracic Society for disease due to nontuberculous mycobacteria do not seem ap plicable to M. xenopi in HIV-infected patients. We suggest that two po sitive cultures of M. xenopi and no other likely cause of symptoms pre sent should be considered the criteria for diagnosis of M. xenopi dise ase in HIV-infected patients. (C) 1998 Lippincott Williams & Wilkins.