Abstract
Forty three isoniazid (INH)-resistant Mycobacterium tuberculosis isolates were characterized on the basis of the most common INH associated mutations, katG315 and mabA -15C→T, and phenotypic properties (i.e. MIC of INH, resistance associated pattern, and catalase activity). Typing for resistance mutations was performed by Multiplex Allele-Specific PCR and sequencing reaction. Mutations at either codon were detected in 67.5% of isolates: katG315 in 37.2, mabA -15C→T in 27.9 and both of them in 2.4%, respectively. katG sequencing showed a G insertion at codon 325 detected in 2 strains and leading to amino acid change T326D which has not been previously reported. Distribution of each mutation, among the investigated strains, showed that katG S315T was associated with multiple-drug profile, high-level INH resistance and loss or decreased catalase activity; whereas the mabA -15C→T was more prevalent in mono-INH resistant isolates, but it was not only associated with a low-level INH resistance. It seems that determination of catalase activity aids in the detection of isolates for which MICs are high and could, in conjunction with molecular methods, provide rapid detection of most clinical INH-resistant strains.
Citations
Citations to this article as recorded by

- Mutations in rpoB and katG genes and the inhA operon in multidrug-resistant Mycobacterium tuberculosis isolates from Zambia
Eddie S. Solo, Chie Nakajima, Trevor Kaile, Precious Bwalya, Grace Mbulo, Yukari Fukushima, Sylvia Chila, Nanthan Kapata, Yogendra Shah, Yasuhiko Suzuki
Journal of Global Antimicrobial Resistance.2020; 22: 302. CrossRef - Mutations of rpoB, katG, inhA and ahp genes in rifampicin and isoniazid-resistant Mycobacterium tuberculosis in Kyrgyz Republic
Jainagul Isakova, Nurmira Sovkhozova, Denis Vinnikov, Zoy Goncharova, Elnura Talaibekova, Nazira Aldasheva, Almaz Aldashev
BMC Microbiology.2018;[Epub] CrossRef - Genotyping and molecular detection of multidrug-resistant Mycobacterium tuberculosis among tuberculosis lymphadenitis cases in Addis Ababa, Ethiopia
O. Zewdie, A. Mihret, T. Abebe, A. Kebede, K. Desta, A. Worku, G. Ameni
New Microbes and New Infections.2018; 21: 36. CrossRef - Evaluation of the GenoType MTBDRplus assay for detection of rifampicin- and isoniazid-resistant Mycobacterium tuberculosis isolates in central Ethiopia
Zufan Bedewi Omer, Yalemtsehay Mekonnen, Adane Worku, Aboma Zewde, Girmay Medhin, Temesgen Mohammed, Rembert Pieper, Gobena Ameni
International Journal of Mycobacteriology.2016; 5(4): 475. CrossRef -
Resistance to Isoniazid and Ethionamide in
Mycobacterium tuberculosis
: Genes, Mutations, and Causalities
Catherine Vilchèze, William R. Jacobs JR., Graham F. Hatfull, William R. Jacobs Jr.
Microbiology Spectrum.2014;[Epub] CrossRef