Rapid Diagnosis of Tuberculosis and Multidrug Resistance Using a MGIT 960 System
Won-Jung Koh, M.D.1,*, Yousang Ko, M.D.1,*, Chang-Ki Kim, M.D.2, Kyung Sun Park, M.D.3, and Nam Yong Lee, M.D.3
Division of Pulmonary and Critical Care Medicine1, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul;
Korean Institute of Tuberculosis2, Osong; Department of Laboratory Medicine & Genetics3, Samsung Medical Center, Sungkyunkwan University School of
Medicine, Seoul, Korea
Correspondence to: Nam Yong Lee
Department of Laboratory Medicine & Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 135-710, Korea
*Won-Jung Koh and Yousang Ko contributed equally to this work
Received: December 2, 2011; Revised: March 19, 2012; Accepted: May 22, 2012
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Background: The purpose of this study was to compare the turnaround time for liquid culturing and primary anti-tuberculous drug susceptibility testing (DST) performed using the mycobacteria growth indicator tube (MGIT) 960 system (Becton Dickinson, USA) with that for conventional culturing and DST (by the absolute concentration method) performed using solid culture medium and to determine the concordance rates of DST results obtained using these 2 methods. Methods: In this retrospective study, we compared the turnaround times from receiving the request for mycobacterial culture to reporting the DST results before and after the introduction of the MGIT 960 system. Further, we determined the concordance between DST results for isoniazid and rifampin for Mycobacterium tuberculosis isolates obtained using the MGIT 960 system and the absolute concentration method, which was conducted at the Korean Institute of Tuberculosis. Results: The overall turnaround time for mycobacterial culturing and DST was 27 days for liquid culturing and DST using the MGIT 960 system versus approximately 70 days for culturing on solid medium and DST with the absolute concentration method (P <0.001). There was a good concordance between findings of DST obtained with the 2 methods (97.2%, kappa coefficient=0.855 for rifampin; and 95.6%, kappa coefficient=0.864 for isoniazid), for 1,083 clinical isolates. Conclusions: The automated MGIT 960 system for culturing and DST of M. tuberculosis was successfully introduced in a hospital laboratory setting in Korea with significant shortening of the turnaround time.
Keywords: Drug resistance, Microbial sensitivity tests, Mycobacterium tuberculosis, Rifampin, Isoniazid