ACLS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Huang, T.-S.
Right arrow Articles by Chen, B.-C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Huang, T.-S.
Right arrow Articles by Chen, B.-C.
Annals of Clinical & Laboratory Science 37:323-329 (2007)
© 2007 Association of Clinical Scientists

Rapid Purity Check Method for Susceptibility Testing of M. tuberculosis Complex with the MGIT 960 System

Tsi-Shu Huang1,2, Yung-Ching Liu1,3, Hui-Zin Tu1, Cheng-Len Sy4, Yao-Shen Chen1,4 and Bao-Chen Chen1
1 Section of Microbiology and Infectious Diseases, Kaohsiung Veterans General Hospital; 2 Department of Medical Technology, Foo-Yin Institute of Technology, 3 Department of Internal Medicine, National Yang-Ming University, and 4 Graduate Institute of Environmental Education, National Kaohsiung Normal University, Kaohsiung, Taiwan

Address correspondence to Dr. Yung-Ching Liu, Section of Infectious Diseases, Kaohsiung Veterans General Hospital, 386 Ta-Chung 1st Rd, Kaohsiung, Taiwan, ROC; tel 07 346 8098; fax 07 346 8296; e-mail tshuang{at}vghks.gov.tw.

The Bactec MGIT 960 system is a rapid and reliable automated method for drug susceptibility testing of Mycobacterium tuberculosis complex (MTBC) that yields a high percentage of agreement with the standard method. The microscopic cord morphology of M. tuberculosis in liquid medium is characteristic, and readily differentiates MTBC from nontuberculous mycobacteria (NTM). The goals of this study were to describe the microscopic and macroscopic growth morphology of MTBC in antimicrobial-containing MGIT tubes and to evaluate the usefulness of the growth appearance during purity checking. The macroscopic cotton wool-like appearance of MTBC isolates in isoniazid (INH), streptomycin (SM), rifampin (RMP), and ethambutol (EMB)-containing tubes was observed in 97, 90, 93, and 71% of the isolates, respectively. The percentage of typical cord, loose, or frayed rope microscopic features in smears prepared from MTBC-positive cultures of INH, SM, RMP, and EMB-containing tubes was 96, 86, 97, and 71%, respectively. The sensitivity of the macroscopic morphology for predicting the purity of drug-containing MGIT tubes was 93%, while the microscopic morphology predicted the purity with a sensitivity rate of 92%. We found that simply examining the macroscopic morphology of the antimicrobial-containing MGIT tubes of drug-resistant MTBC isolates is useful in preventing false resistant results of susceptibility testing by the MGIT 960 system.

Keywords: M. tuberculosis complex, MGIT, antimicrobial susceptibility testing






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2007 by the Association of Clinical Scientists.