Drug resistance of Mycobacterium tuberculosis in Eastern Taiwan

Objective: To evaluate patterns of drug resistance of Mycobacterium tuberculosis in eastern Taiwan. Materials and Methods: Two hundred and fifty-two isolates collected from January 2001 through December 2002 were tested for drug susceptibility using the agar proportion method at Tzu Chi General Hospital. Results: The overall rate of resistance to at least one drug was 28.6%. The overall resistance rates to individual drugs were 21.8% to isoniazid, 8.3% to streptomycin, 12.7% to rifampin, and 12.7% to ethambutol. Among the 190 isolates from patients without prior treatment, 16.8% of the strains were resistant to at least one drug. Resistance to isoniazid (11.1%), ethambutol (5.8%), or streptomycin (5.3%) was more common than resistance to rifampin (2.1%). The prevalence of primary multidrug resistance was 2.1%. Among the 62 isolates from patients with histories of anti-TB treatment, the prevalence of resistance to any of the four drugs was 64.5%. The acquired resistance rates to individual drugs were 54.8% to isoniazid, 17.7% to streptomycin, 45.2% to rifampin, and 33.9% to ethambutol. Conclusions: The prevalence of drug resistance is very high in eastern Taiwan, and the surveys for anti-tuberculosis drug resistance should be repeated annually. Measures to decrease the multidrug-resistance rate are greatly needed.