Title: The relationship between mutations in katG, inhA, ahpC and other genes of Mycobacterium tuberculosis and isoniazid resistance
Abstract:Objective To understand the relationship between characteristics of mutations in katG, inhA, ahpC, fabG1, sodA, and sodC genes of Mycobacterium tuberculosis and isoniazid(INH) resistance. Methods A to...Objective To understand the relationship between characteristics of mutations in katG, inhA, ahpC, fabG1, sodA, and sodC genes of Mycobacterium tuberculosis and isoniazid(INH) resistance. Methods A total of 127 Mycobacterium tuberculosis clinical isolates from sputum of patients with active pulmonary tuberculosis were collected and used for mycobacterium species identification, drug susceptibility testing and extraction of genomic DNA. DNA fragments specific for katG, inhA, ahpC, fabG1, sodA and sodC genes were amplified by PCR and used for sequence analysis and comparison with the standard laboratory strains(H37RV) through the use of NCBI database. Results Out of 127 clinical isolates tested for INH susceptibility, 47(37.01%) were resistant and 80 were susceptible to INH. Among 47 INH-resistant isolates, 29 had mutations in katG and/or inhA genes, 22(46.81%, 22/47) had point mutation in katG gene, 3(6.38%, 3/47) had mutation in the promoter region of inhA gene, and 4(8.51%, 4/47) had point mutations in both katG and inhA genes. Among 22 isolates with mutation in katG gene, 20(42.55%, 20/47) had mutation at codon 315(AGC315ACC or AGC315AAC) and 2(2.13%, 1/47) had mutation at codons 378(CTG378CCG, Leu378Pro) and 394(ACG394ACC, Thr394Met). In 18 isolates without mutations in katG and inhA genes, no mutation was detected in ahpC, fabG1, sodA and sodC genes. Conclusion Results from this study further confirm that mutations in katG and inhA genes of Mycobacterium tuberculosis are associated with isoniazid resistance. Two new point mutations in the katG gene have been identified from the study, which will provide new information for further development of quick diagnostic methods for drug-resistant tuberculosis.Read More
Publication Year: 2013
Publication Date: 2013-01-01
Language: en
Type: article
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