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Updated: Jun 15, 2026

Demonstrating a Multi-drug Resistant Mycobacterium tuberculosis Amplification Microarray
Published on: April 25, 2014
Identification of katG mutations associated with high-level isoniazid resistance in Mycobacterium tuberculosis
Hiroki Ando1, Yuji Kondo, Toshinori Suetake
1Department of Infectious Diseases, Research Institute, International Medical Center of Japan, Tokyo, Japan.
Abstract:
Isoniazid (INH) is an effective first-line antituberculosis drug. KatG, a catalase-peroxidase, converts INH to an active form in Mycobacterium tuberculosis, and katG mutations are major causes of INH resistance. In the present study, we sequenced katG of 108 INH-resistant M. tuberculosis clinical isolates. Consequently, 9 novel KatG mutants with a single-amino-acid substitution were found. All of these mutants had significantly lower INH oxidase activities than the wild type, and each mutant showed various levels of activity. Isolates having mutations with relatively low activities showed high-level INH resistance. On the basis of our results and known mutations associated with INH resistance, we developed a new hybridization-based line probe assay for rapid detection of INH-resistant M. tuberculosis isolates.
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