Journal List > Korean J Clin Microbiol > v.11(1) > 1038147

Korean J Clin Microbiol. 2008 Apr;11(1):43-48. Korean.
Published online April 30, 2008.
Copyright © 2008 The Korean Society of Clinical Microbiology
Comparison of Anti-mycobacterial Drug Susceptibility Test Results by Institutes and Methods
Seung Hwan Oh,1,2 Young Jin Kim,1 Seung Kyu Park,2 Sang Hyun Hwang,1 Hyung Hoi Kim,1 Eun Yup Lee,1 and Chulhun L. Chang1,3
1Department of Laboratory Medicine, Pusan National University School of Medicine, Busan, Korea.
2National Masan Hospital, Masan, Korea.
3Korean Institute of Tuberculosis, Seoul, Korea.

Correspondence: Chulhun L. Chang, Department of Laboratory Medicine, School of Medicine, Pusan National University, 10, Ami-dong 1-ga, Seo-gu, Busan 602-739, Korea. (Tel) 82-51-240-7417, (Fax) 82-51-247-6560, Email:
Received January 14, 2008; Accepted February 26, 2008.



The purposes of the current study were to evaluate the concordant rates of anti-mycobacterial drug susceptibility test (DST) results in different solid media performed in different institutes, and to determine reliable susceptible testing methods.


One hundred and twenty two Mycobacterium tuberculosis strains were isolated from patients in A Hospital in 2005. DSTs were performed by the absolute concentration method using Löwenstein Jensen medium in both A Hospital (method A-1) and B Institute (method B-1) and by the proportion method using Middlebrook 7H10 agar in B Institute (method B-2). Nine drugs were used including isoniazid and rifampin. Sensitivity and specificity of each method were estimated by using the acceptable standard of 90% for isoniazid and rifampin and 80% for other drugs. The therapeutic outcomes of quinolone-administered patients were evaluated according to ofloxacin susceptibility results.


Method B-1 showed sensitivity and specificity levels over the acceptable standard levels for all drugs. Method B-2 showed specificity lower than the acceptable levels for rifampin and cycloserine. Method A-1 showed specificity lower than the acceptable levels for isoniazid, streptomycin, p-aminosalicylic acid, and ofloxacin and sensitivity lower than the acceptable levels for prothionamide and cycloserine. The concordance rates of therapeutic outcomes with method B-1, method B-2, and method A-1 were 77%, 74%, and 65%, respectively.


The drug susceptibility results for some drugs were discordant between the testing laboratories and media, requiring an urgent application of quality control programs to raise the reliability of anti-mycobacterial DST.

Keywords: Mycobacterium tuberculosis; Drug susceptibility tests; Culture Media


Table 1
Critical concentrations (µg/mL) of drugs
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Table 2
Test performance of each drug tested by three methods in two laboratories
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Table 3
Test efficiencies of each method in 57 patients with ofloxacin or levofloxacin prescription
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