Rapid purity check method for susceptibility testing of M. tuberculosis complex with the MGIT 960 system

Tsi S. Huang, Yung Ching Liu, Hui Z. Tu, Cheng L. Sy, Yao Shen Chen, Bao Chen Chen

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)323-329
Number of pages7
JournalAnnals of Clinical and Laboratory Science
Volume37
Issue number4
Publication statusPublished - Sep 2007
Externally publishedYes

Fingerprint

Mycobacterium tuberculosis
Tuberculosis
Testing
Ethambutol
Streptomycin
Rifampin
Pharmaceutical Preparations
Isoniazid
Wool
Cotton
Nontuberculous Mycobacteria
Multidrug-Resistant Tuberculosis
Growth
Liquids

Keywords

  • Antimicrobial susceptibility testing
  • M. Tuberculosis complex
  • MGIT

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Clinical Biochemistry

Cite this

Rapid purity check method for susceptibility testing of M. tuberculosis complex with the MGIT 960 system. / Huang, Tsi S.; Liu, Yung Ching; Tu, Hui Z.; Sy, Cheng L.; Chen, Yao Shen; Chen, Bao Chen.

In: Annals of Clinical and Laboratory Science, Vol. 37, No. 4, 09.2007, p. 323-329.

Research output: Contribution to journalArticle

Huang, Tsi S. ; Liu, Yung Ching ; Tu, Hui Z. ; Sy, Cheng L. ; Chen, Yao Shen ; Chen, Bao Chen. / Rapid purity check method for susceptibility testing of M. tuberculosis complex with the MGIT 960 system. In: Annals of Clinical and Laboratory Science. 2007 ; Vol. 37, No. 4. pp. 323-329.
@article{96bbafe625a040ed8596c96774777e93,
title = "Rapid purity check method for susceptibility testing of M. tuberculosis complex with the MGIT 960 system",
abstract = "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 = "Antimicrobial susceptibility testing, M. Tuberculosis complex, MGIT",
author = "Huang, {Tsi S.} and Liu, {Yung Ching} and Tu, {Hui Z.} and Sy, {Cheng L.} and Chen, {Yao Shen} and Chen, {Bao Chen}",
year = "2007",
month = "9",
language = "English",
volume = "37",
pages = "323--329",
journal = "Annals of Clinical and Laboratory Science",
issn = "0091-7370",
publisher = "Association of Clinical Scientists",
number = "4",

}

TY - JOUR

T1 - Rapid purity check method for susceptibility testing of M. tuberculosis complex with the MGIT 960 system

AU - Huang, Tsi S.

AU - Liu, Yung Ching

AU - Tu, Hui Z.

AU - Sy, Cheng L.

AU - Chen, Yao Shen

AU - Chen, Bao Chen

PY - 2007/9

Y1 - 2007/9

N2 - 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.

AB - 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.

KW - Antimicrobial susceptibility testing

KW - M. Tuberculosis complex

KW - MGIT

UR - http://www.scopus.com/inward/record.url?scp=36148932170&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=36148932170&partnerID=8YFLogxK

M3 - Article

C2 - 18000288

AN - SCOPUS:36148932170

VL - 37

SP - 323

EP - 329

JO - Annals of Clinical and Laboratory Science

JF - Annals of Clinical and Laboratory Science

SN - 0091-7370

IS - 4

ER -