Screening and characterization of mutations in isoniazid-resistant Mycobacterium tuberculosis isolates obtained in Brazil.
نویسندگان
چکیده
We investigated mutations in the genes katG, inhA (regulatory and structural regions), and kasA and the oxyR-ahpC intergenic region of 97 isoniazid (INH)-resistant and 60 INH-susceptible Mycobacterium tuberculosis isolates obtained in two states in Brazil: São Paulo and Paraná. PCR-single-strand conformational polymorphism (PCR-SSCP) was evaluated for screening mutations in regions of prevalence, including codons 315 and 463 of katG, the regulatory region and codons 16 and 94 of inhA, kasA, and the oxyR-ahpC intergenic region. DNA sequencing of PCR amplicons was performed for all isolates with altered PCR-SSCP profiles. Mutations in katG were found in 83 (85.6%) of the 97 INH-resistant isolates, including mutations in codon 315 that occurred in 60 (61.9%) of the INH-resistant isolates and 23 previously unreported katG mutations. Mutations in the inhA promoter region occurred in 25 (25.8%) of the INH-resistant isolates; 6.2% of the isolates had inhA structural gene mutations, and 10.3% had mutations in the oxyR-ahpC intergenic region (one, nucleotide -48, previously unreported). Polymorphisms in the kasA gene occurred in both INH-resistant and INH-susceptible isolates. The most frequent polymorphism encoded a G(269)A substitution. Although KatG(315) substitutions are predominant, novel mutations also appear to be responsible for INH resistance in the two states in Brazil. Since ca. 90.7% of the INH-resistant isolates had mutations identified by SSCP electrophoresis, this method may be a useful genotypic screen for INH resistance.
منابع مشابه
Isoniazid MIC and KatG Gene Mutations among Mycobacterium tuberculosis Isolates in Northwest of Iran
Objective(s) Isoniazid (INH) is one of the main first line drugs used in treatment of tuberculosis and development of resistance against this compound can result in serious problems in treatment procedures. Resistance to INH is mediated mainly by mutation in KatG gene that is coded for the catalase enzyme. The proportional method for detection of INH-resistance is time consuming due to the slo...
متن کاملCharacterization of Mutations in the Rpob and Katg Gene of Mycobacterium Tuberculosis Isolates From Pasteur Institute of Tehran
Objective: The Rifampicin resistance and susceptibility of Mycobacterium tuberculosis are caused by mutations in the 81-base pair region of the rpoB gene encoding the b-subunit of RNA polymerase. Methods: Isoniazid resistance of M. tuberculosis is related to mutations in inha , oxyR and ahpC genes which 30 to 90 percent of Isoniazid resistance is occurred in 3015 codons of kat...
متن کاملتشخیص موتاسیون در کدون 315 ژن katG، مارکر مقاومت به ایزونیازید در سوش‌های مایکوباکتریوم توبرکولوزیس جدا شده از بیماران اصفهان و تهران با روش PCR-RFLP
Background and Objective: Drug resistance to tuberculosis is continuously increasing and is a significant threat to tuberculosis control programs because afew effective drugs are present against Mycobacterium tuberculosis. Although isoniazid (INH) is the most effective drug against tuberculosis, resistance to this drug also develops readily. Mutations in katG, specially the Ser315Thr substituti...
متن کاملCharacterization of Mutations in the Rpob and Katg Gene of Mycobacterium Tuberculosis Isolates From Pasteur Institute of Tehran
Objective: The Rifampicin resistance and susceptibility of Mycobacterium tuberculosis are caused by mutations in the 81-base pair region of the rpoB gene encoding the b-subunit of RNA polymerase. Methods: Isoniazid resistance of M. tuberculosis is related to mutations in inha , oxyR and ahpC genes which 30 to 90 percent of Isoniazid resistance is occurred in 3015 codons of kat...
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ورودعنوان ژورنال:
- Antimicrobial agents and chemotherapy
دوره 48 9 شماره
صفحات -
تاریخ انتشار 2004