Identification of the mutation in KAT and INH a genes of isoniazid resistant mycobacterium tuberculosis.
ABSTRACT: Alteration of katG gene spanning codons 275,309,315,328,463,516 and inhA gene at upstream positions -8,-15,-24 or codons 16,21,94,95 have been reported frequently as the root causes of isoniazid resistance in Mycobacterium tuberculosis. In the present study, 29 multi-drug resistant/isonia...
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| Language: | English |
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c2005.
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| Summary: | ABSTRACT: Alteration of katG gene spanning codons 275,309,315,328,463,516 and inhA gene at upstream positions -8,-15,-24 or codons 16,21,94,95 have been reported frequently as the root causes of isoniazid resistance in Mycobacterium tuberculosis. In the present study, 29 multi-drug resistant/isoniazid resistant Mycobacterium tuberculosis (MDR/INHr -MTB) isolates obtained from patients with tuberculosis were analyzed for mutation in katG and inhA genes. In these samples, the coding region of katG gene encoding catalase-peroxidase and both promoter region and open reading frame (ORF) of inhA gene encoding enoyl-acyl carrier protein reductase were amplified by polymerase chain reaction (PCR). The H37Ra strain which is isoniazid susceptible Mycobacterium tuberculosis (INHs-MTB) was used as control. PCR-DNA sequencing identified the specific mutation positions in those regions of both genes, whereas,PCR-single strand conformation polymorphism (PCR-SSCP) technique was applied to screen the mutations in both of these genes. PCR-DNA sequencing has shown in all 29 isolates exhibiting single point mutation at one or two positions (p< 0.05) of katG gene (only Ser315 Thr 3.4%, only Arg463 Leu 34.5%,both Ser315Thr and Arg463Leu 58.6%, Thr308 Pro 3.4%). Similarly, 9 of 29 isolates were identified as mutants in inhA promoter and inhA-ORF, of which 5 isolates Cytosine - Thymine at position -15 (17.2%). 1 isolate Thymine - Cytosine at upstream position -8 (3.4%), 1 isolate Cytosine - Thymine at position -15 plus Ile21Thr (3.4%), 1 isolate Cytosine -Thymine at position -15 plus Ser94Ala (3.4%) and 1 isolate at I1e21Val (3.4%) position. The number and percentage of isolates (69.0%) had no mutation at any positions. Trp308Pro of katG and Thymine-Cytosine at position -8 of inhA genes less significant than those of non-mutants (p> 0.05). This is the first time that the two genes were identified. No frame shift mutation has been observed in any of the isolates. This is also the first time that the mutation positions in inhA gene were identified in Thai INHr -MTB isolates. Keywords: Identification /mutation / katG /inhA / isoniazid resistant / Mycobacterium tuberculosis |
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| Item Description: | Thesis Report. |
| Physical Description: | vii, 78p. : |