Emergence of multidrug-resistant tuberculosis in a community-based directly observed treatment programme in rural South Africa

OBJECTIVE: Although little studied in developing countries, multidrug-resis tant tuberculosis (MDR-TB) is considered a major threat. We report the mole cular epidemiology, clinical features and outcome of an emerging MDR-TB epi demic. METHODS: In 1996 all tuberculosis suspects in the rural Hlabisa district, S outh Africa, had sputum cultured, and drug susceptibility patterns of mycob acterial isolates were determined. Isolates with MDR-TB (resistant to both isoniazid and rifampicin) were DNA fingerprinted by restriction fragment le ngth polymorphism (RFLP) using IS6110 and polymorphic guanine-cytosine-rich sequence-based (PGRS) probes. Patients with MDR-TB were traced to determin e outcome. Data were compared with results from a survey of drug susceptibi lity done in 1994. RESULTS: The rate of MDR-TB among smear-positive patients increased six-fol d from 0.36% (1/275) in 1994 to 2.3% (13/561) in 1996 (P = 0.04). A further eight smear-negative cases were identified in 1996 from culture, six of wh om had not been diagnosed with tuberculosis. MDR disease was clinically sus pected in only five of the 21 cases (24%). Prevalence of primary and acquir ed MDR-TB was 1.8% and 4.1%, respectively. Twelve MDR-TB cases (67%) were i n five RFLP-defined clusters. Among 20 traced patients, 10 (50%) had died, five had active disease (25%) and five (25%) were apparently cured. CONCLUSIONS: The rate of MDR-TB has risen rapidly in Hlabisa, apparently du e to both reactivation disease and recent transmission. Many patients were not diagnosed with tuberculosis and many were not suspected of drug-resista nt disease, and outcome was poor.