A survey of drug-resistant Mycobacterium tuberculosis and its relationship to HIV infection

Objective: To compare the prevalence of drug-resistant tuberculosis disease among patients with and without HIV infection. Design: An historical prospective evaluation of patients with culture-proven tuberculosis reported between January 1988 and December 1995. Setting: A major metropolitan county public health department. Patients: A total of 802 consecutive culture-positive tuberculosis patients were eligible for inclusion in the study. HIV serologic testing and drug susceptibilities were completed on 741 (92%) eligible patients. Of these patients, 646 tested HIV-negative and 95 (12.8%) tested HIV-positive. Patients not tested for HIV (n = 59) and without drug susceptibilities (n = 2) were excluded from the analyses. Outpatient management was based on a policy of universal directly observed therapy. Main outcome measures: Patient HIV status, initial drug resistance and acquired drug resistance. Isolates were characterized for resistance to isoniazid, rifampin, rifabutin, ethambutol, streptomycin, capreomycin, kanamycin and ethionamide. Determination of initial resistance was based on the first available susceptibility study and acquired resistance on subsequent susceptibility studies. Results: Initial drug resistance was found in 55 (8.5%) HIV-negative patients and four (4.2%) HIV-positive patients. Acquired drug resistance occurred in five (0.8%) HIV-negative patients and one (1.1%) HIV-positive patient. These differences were not statistically significant. Conclusions: HIV infection is not a risk factor for drug-resistant tuberculosis. Increased drug resistance in HIV infected tuberculosis patients reflects a failure of tuberculosis control in the underlying population.