Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology


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pISSN 2288-0585 eISSN 2288-6850

Comparison of Anti-mycobacterial Drug Susceptibility Test Results by Institutes and Methods

Original article

Annals of Clinical Microbiology (Ann Clin Microbiol) 2008 April Volume 11, Issue 1, pages 43-48.

Comparison of Anti-mycobacterial Drug Susceptibility Test Results by Institutes and Methods

Seung Hwan Oh1,2, Young Jin Kim1, Seung Kyu Park2, Sang Hyun Hwang1, Hyung Hoi Kim1, Eun Yup Lee1, Chulhun L. Chang1,3
1Department of Laboratory Medicine, Pusan National University School of Medicine, Busan; 2National Masan Hospital, Masan; 3Korean Institute of Tuberculosis, Seoul, Korea


Background: 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.

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.

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.

Conclusion: 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. (Korean J Clin Microbiol 2008; 11:43-48)


Mycobacterium tuberculosis, Drug susceptibility tests, Culture Media