Improving antitubercular drug susceptibility testing with liquid media

Sang Mee Hwang, Kil Chae Hwang, Yun Ji Hong, Hye Ryun Lee, Taek Soo Kim, Kyoung Un Park, Junghan Song, Jaeho Lee, Eui Chong Kim

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Liquid media such as the mycobacteria growth indicator tube (MGIT) are widely used for antitubercular drug susceptibility testing (DST) but may cause discordant or invalid results due to ordinary bacterial contamination or mixed mycobacterial colonies. To overcome the drawbacks of DST with MGIT (DSTMGIT), an experiment with a modified method that incorporated a subculture step on the Löwenstein-Jensen (LJ) media with positively identified liquid media of MGIT (modified DSTMGIT) was performed. For 307 samples identified as Mycobacterium tuberculosis complex from 2010 to 2012, DSTMGIT and modified DSTMGIT were performed for isoniazid, rifampin, streptomycin, and ethambutol using BACTEC MGIT 960. Those results were compared to the results of DST with the solid media, LJ (DSTLJ). We obtained drug susceptibility test results from 287 (93.5%) specimens; however, 20 (6.5%) specimens showed invalid results with error messages from the system using DSTMGIT. Thirteen (65.0%) of the 20 invalid DSTMGIT results were made valid using a modified form of DSTMGIT. DSTMGIT and the modified DSTMGIT methods had 41 (14.3%) discordant results to the reference method, DSTLJ. Also, five of these samples were falsely identified as multidrug-resistant. The percent of discordant results was similar between DSTMGIT and the modified DSTMGIT (P=0.624), but the bacterial contamination or mycobacterial mixture rate was significantly lower in the modified DSTMGIT (P=0.029). Modified DSTMGIT can reduce bacterial contamination or mixed mycobacterial cultures and can be useful for samples with discordant or invalid DST results.

Original languageEnglish
Pages (from-to)123-130
Number of pages8
JournalAnnals of Clinical and Laboratory Science
Volume44
Issue number2
StatePublished - 1 Jan 2014

Fingerprint

Antitubercular Agents
Mycobacterium
Contamination
Liquids
Testing
Growth
Pharmaceutical Preparations
Ethambutol
Isoniazid
Streptomycin
Rifampin
Mycobacterium tuberculosis
Experiments

Keywords

  • Löwenstein-Jensen media
  • Mycobacteria growth indicator tube
  • Mycobacterium tuberculosis complex

Cite this

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title = "Improving antitubercular drug susceptibility testing with liquid media",
abstract = "Liquid media such as the mycobacteria growth indicator tube (MGIT) are widely used for antitubercular drug susceptibility testing (DST) but may cause discordant or invalid results due to ordinary bacterial contamination or mixed mycobacterial colonies. To overcome the drawbacks of DST with MGIT (DSTMGIT), an experiment with a modified method that incorporated a subculture step on the L{\"o}wenstein-Jensen (LJ) media with positively identified liquid media of MGIT (modified DSTMGIT) was performed. For 307 samples identified as Mycobacterium tuberculosis complex from 2010 to 2012, DSTMGIT and modified DSTMGIT were performed for isoniazid, rifampin, streptomycin, and ethambutol using BACTEC MGIT 960. Those results were compared to the results of DST with the solid media, LJ (DSTLJ). We obtained drug susceptibility test results from 287 (93.5{\%}) specimens; however, 20 (6.5{\%}) specimens showed invalid results with error messages from the system using DSTMGIT. Thirteen (65.0{\%}) of the 20 invalid DSTMGIT results were made valid using a modified form of DSTMGIT. DSTMGIT and the modified DSTMGIT methods had 41 (14.3{\%}) discordant results to the reference method, DSTLJ. Also, five of these samples were falsely identified as multidrug-resistant. The percent of discordant results was similar between DSTMGIT and the modified DSTMGIT (P=0.624), but the bacterial contamination or mycobacterial mixture rate was significantly lower in the modified DSTMGIT (P=0.029). Modified DSTMGIT can reduce bacterial contamination or mixed mycobacterial cultures and can be useful for samples with discordant or invalid DST results.",
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Improving antitubercular drug susceptibility testing with liquid media. / Hwang, Sang Mee; Hwang, Kil Chae; Hong, Yun Ji; Lee, Hye Ryun; Kim, Taek Soo; Park, Kyoung Un; Song, Junghan; Lee, Jaeho; Kim, Eui Chong.

In: Annals of Clinical and Laboratory Science, Vol. 44, No. 2, 01.01.2014, p. 123-130.

Research output: Contribution to journalArticle

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AU - Hwang, Sang Mee

AU - Hwang, Kil Chae

AU - Hong, Yun Ji

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AU - Kim, Eui Chong

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