Background : Tuberculosis is still one of the most seriously threatening infections in Korea, because of multidrug resistant tuberculosis. Results of antituberculosis drug susceptibility test can provide clinicians very important informations for selection of proper regimens for treatment. 

Methods : In this study the results of antituberculosis drug susceptibility test of 298 cases at Kyunghee Medical Center from 2000 to 2003 were retrospectively analysed to evaluate the trend of antituberculosis drug susceptibility. The procedure of drug susceptibility test was based on the absolute concentration method using Lowenstein-Jensen solid media. 

Results : The resistance rate of Mycobacterium tuberculosis to one or more drugs was increased from 29.3% in 2000 to 48.2% in 2003, and the rates of multiple resistance to two or more drugs increased from 13.3% in 2000 to 20.5% in 2003. The increase in resistance rate to individual drug during study period were 20.0% to 24.1% in isoniazid, 9.3% to 19.3% in rifampicin, 5.3% to 15.7% in ethambutol, 4.0% to 10.8% in para-aminosalicylic acid, 2.7% to 6.0% in kanamycin, 1.3% to 7.2% in ethionamide, 1.3% to 6.0% in capreomycin, 1.3% to 7.2% in prothionamide, 0.0% to 12.1% in ofloxacin, 6.7% to 3.6% in streptomycin, 6.7% to 7.2% in cycloserine, 10.7% to 8.4%in pyrazinamide, respectively. 

Conclusions : The resistance rate of M. tuberculosis has been increased with years and multidrug resistant M. tuberculosis was commonly encountered in the specimens from the patients visited Kyunghee Medical center. (Korean J Clin Microbiol 2004;7(2):182-185)