THE CHANGING EPIDEMIOLOGY OF ACQUIRED DRUG-RESISTANT TUBERCULOSIS IN SAN-FRANCISCO, USA

Background The increasing incidence of tuberculosis caused by drug-res istant Mycobacterium tuberculosis is thought in part to reflect inadeq uate implementation of standard tuberculosis control measures. However , in San Francisco, USA, which has an effective tuberculosis control p rogramme, we have recently observed an increase in cases of acquired d rug-resistance. Methods To explore further this observation, we analys ed the secular trend of acquired drug-resistance and conducted a popul ation-based case-control study oi all reported tuberculosis cases In t he city of San Francisco between 1985 and 1994. Findings We identified 14 patients with tuberculosis caused by fully susceptible M tuberculo sis who subsequently developed drug-resistance. Of these acquired drug -resistance cases, two occurred between 1985 and 1989, whereas 12 occu rred between 1990 and 1994 (p=0.028); In the case-contra[ study, AIDS 20.2, 95% CI 1.12-363.6), nan;compliance with therapy (19.7, 1.66-234. 4), and gastrointestinal symptoms (11.5, 1.23-107.0) were independentl y associated with acquired drug-resistance; Between 1990 and 1994, one in 16 tuberculosis patients with AIDS and either gastrointestinal sym ptoms or non-compliance developed acquired drug-resistance. Interpreta tion The substantial increase in acquired drug-resistance in San Franc isco seems to bera product of the increasing prevalence: of HIV/M tube rculosis coinfection. Our data suggest that the interface of the HIV a nd tuberculosis epidemics fosters acquired drug-resistance, and that t raditional tuberculosis control measures may not be sufficient in comm unities with high rates of HIV infection.