A continuing survey of drug-resistant tuberculosis, New York City, April 1994

Background: A 1991 survey showed high levels of drug resistance among tuberculosis patients in New York, NY. As a result, the tuberculosis control program was strengthened, including expanded use of directly observed therapy and improved infection control. Methods: We collected isolates from every patient in New York City with a positive culture for Mycobacterium tuberculosis during April 1994; results were compared with those in the April 1991 survey. Results: From 1991 to 1994, the number of patients decreased from 466 to 332 patients. The percentage with isolates resistant to 1 or more antituberculosis drugs decreased from 33% to 24% (P<.01); with isolates resistant to at least isoniazid decreased from 26% to 18% (P<.05); and with isolates resistant to both isoniazid and rifampin decreased from 19% to 13% (P<.05). The number of patients with isolates resistant to both isoniazid and rifampin decreased by more than 50%. Among never previously treated patients, the percentage with resistance to 1 or more drugs decreased from 22% in 1991 to 13% in 1994 (P<.05). The number of patients with consistently positive culture results for more than 4 months decreased from 130 to 44. A history of antituberculosis treatment was the strongest predictor of drug resistance (odds ratio=3.1; P<.001). Human immunodeficiency virus infection was associated with drug resistance among patients who never had been treated for tuberculosis. Conclusions: Drug-resistant tuberculosis declined significantly in New York City from 1991 to 1994. Measures to control and prevent tuberculosis were associated with a 29% decrease in the proportion of drug resistance and a 52% decrease in the number of patients with multidrug-resistant tuberculosis.