Low levels of drug resistance amidst rapidly increasing tuberculosis and human immunodeficiency virus co-epidemics in Botswana

SETTING: Botswana, southern Africa, where the tuberculosis (TB) case rate i ncreased by 120% from 1989 to 1996 in spite of a decade of implementation o f the directly observed therapy, short-course (DOTS) strategy. OBJECTIVE: To determine prevalence of and risk factors for drug-resistant t uberculosis in an epidemic setting. DESIGN: Systematic national random survey of newly diagnosed pulmonary TB a nd all patients with TB requiring retreatment during 1995-1996. Interviews were conducted, human immunodeficiency virus (HIV) testing was offered, and drug susceptibility testing was performed for isoniazid, rifampicin, strep tomycin and ethambutol. RESULTS: Resistance to at least one drug was identified in 16 (3.7%) new ca ses and 18 (14.9%) retreatment cases. One (0.2%) new and seven (5.8%) retre atment cases had resistance to at least both isoniazid and rifampicin (mult idrug-resistant TB). Retreatment cases with multidrug-resistant TB were sig nificantly more likely to have worked in the mines in South Africa than wer e cases with fully susceptible isolates (6/7 [85.7%] versus 32/103 [31.1%], odds ratio 13.3, 95% confidence interval 1.5-311.0, P = 0.007). Of 240 pat ients tested for HIV, 117 (48.8%) were positive; prevalence was similar amo ng new and retreatment cases, and was not a risk factor for drug resistance in either group. CONCLUSION: During the HIV and TB co-epidemics in sub-Saharan Africa, DOTS may help to control drug-resistant TB. However, the TB case rate can be exp ected to continue to climb in spite of the implementation of the DOTS strat egy.