Drug-resistant tuberculosis in Taipei, 1996-1999

To determine the trends, patterns, and risk factors associated with drug-resistant tuberculosis, we conducted a hospital-based retrospective study in Taipei.

Clinical and bacteriologic data were routinely collected from 453 patients with a diagnosis of tuberculosis who were treated at Taipei Municipal Chronic Disease Hospital from January 1996 through December 1999 for whom drug-susceptibility testing was done.

Resistance to at least one drug was identified in 154 (34%) out of the 453 patients, and 34 (7.5%) patients were resistant to at least isoniazid and rifampin. Among the 199 patients with recurrent tuberculosis, 98 (49.2%) had isolates that showed resistance to at least one drug. Among the 254 new patients, 56 (22.0%) had isolates that were drug resistant. For all 453 patients, resistance to rifampin was most common (17.4%), followed by resistance to isoniazid (13.9%), streptomycin (13.7%), ethambutol (8.2%), and kanamycin (3.5%). A history of previous tuberculosis therapy (odds ratio = 9.4; 95% CI, 2.9-28) and being born outside of Taiwan (odds ratio 3.3; 95% CI, 1.1-34) were significant risk factors for multidrug resistance.

Our data suggest that the Taipei tuberculosis control program should be rapidly strengthened by expanded use of directly observed therapy and more careful bacteriologic and clinical follow-up, particularly in cases of recurrence and in persons born outside of Taiwan in tuberculosis endemic areas. Our results also indicate that the regular measuring of rates of drug resistance and the monitoring and guiding of tuberculosis treatment programs could increase the therapeutic response rate and prevent the appearance of newly acquired resistance in patients with tuberculosis. In addition, with high rifampin resistance (17.4%), the regulated market for rifampin is essential in Taiwan.