Primary and acquired resistance of Mycobacterium tuberculosis in western Mexico

Resistance of Mycobacterium tuberculosis to antimycobacterial agents is a w orldwide problem. The proposite of this study was to analyze the current re sistance patterns of patients with initial episodes, as well as relapses, d ue to M. tuberculosis in western Mexico. From January 1993 to February 1999 a total of 237 strains of M. tuberculosis (120 from initial cases and 117 from relapse cases) were analyzed. Two hundred and four (86%) strains were isolated from the lower respiratory tract, and 33 strains (14%) from extrap ulmonary sites. Twenty-three percent of M, tuberculosis isolated from patie nts with initial episodes were resistant to both isoniazid and rifampin, an d 52% of M, tuberculosis isolated from relapse cases were also resistant to both isoniazid and rifampin.