Drug resistance among tuberculosis patients, New York City, 1991 and 1992

The authors assessed drug susceptibility patterns among tuberculosis patients reported to the New York City Department of Health in the first quarters of 1991 and 1992. Resistance to one or more drugs was seen in 26 percent (137 divided by 520) in 1991 and 24 percent (122 divided by 517) in 1992. Resistance to isoniazid was seen in 22 percent and 19 percent of patients in 1991 and 1992, respectively; resistance to rifampin in 15 percent and 14 percent; and to both isoniazid and rifampin in 15 percent and 14 percent. Combined resistance to four first line drugs (isoniazid, rifampin, streptomycin, and ethambutol) was seen in 6 percent (1991) and 8 percent (1992). Patients with organisms resistant to both isoniazid and rifampin were as likely among U.S. born as among foreign born, and younger patients were more likely than older patients to have isoniazid and rifampin resistant organisms. These findings underscore the importance of obtaining susceptibility testing in all patients who have cultures positive for Mycobacterium tuberculosis.