Tuberc Respir Dis.  2019 Apr;82(2):143-150. 10.4046/trd.2018.0027.

Correlation between GenoType MTBDRplus Assay and Phenotypic Susceptibility Test for Prothionamide in Patients with Genotypic Isoniazid Resistance

• Lee JH
• Jo KW
• Shim TS

• KMID: 2453984
• DOI: http://doi.org/10.4046/trd.2018.0027

Abstract

BACKGROUND
The purpose of this study was to analyze the relationship between the gene mutation patterns by the GenoType MTBDRplus (MTBDRplus) assay and the phenotypic drug susceptibility test (pDST) results of isoniazid (INH) and prothionamide (Pto).
METHODS
A total of 206 patients whose MTBDRplus assay results revealed katG or inhA mutations were enrolled in the study. The pDST results were compared to mutation patterns on the MTBDRplus assay.
RESULTS
The katG and inhA mutations were identified in 68.0% and 35.0% of patients, respectively. Among the 134 isolated katG mutations, three (2.2%), 127 (94.8%) and 11 (8.2%) were phenotypically resistant to low-level INH, high-level INH, and Pto, respectively. Among the 66 isolated inhA mutations, 34 (51.5%), 18 (27.3%) and 21 (31.8%) were phenotypically resistant to low-level INH, high-level INH, and Pto, respectively. Of the 34 phenotypic Pto resistant isolates, 21 (61.8%), 11 (32.4%), and two (5.9%) had inhA, katG, and both gene mutations.
CONCLUSION
It is noted that Pto may still be selected as one of the appropriate multidrug-resistant tuberculosis regimen, although inhA mutation is detected by the MTBDRplus assay until pDST confirms a Pto resistance. The reporting of detailed mutation patterns of the MTBDRplus assay may be important for clinical practice, rather than simply presenting resistance or susceptibility test results.

Keyword

katG Protein; InhA Protein; Isoniazid; Prothionamide; Genotype; Biological Assay; Disease Susceptibility; Research Design; Mycobacterium tuberculosis; Mycobacterium

MeSH Terms

Biological Assay
Disease Susceptibility
Genotype*
Humans
Isoniazid*
Mycobacterium
Mycobacterium tuberculosis
Prothionamide*
Research Design
Tuberculosis, Multidrug-Resistant
Isoniazid
Prothionamide