title: Genotypic analysis of genes associated with isoniazid and ethionamide resistance in MDR-TB isolates from Thailand.
abstract: Nucleotide sequences of genes conferring isoniazid resistance (katG, inhA, oxyR-ahpC and ndh) and ethionamide resistance (ethA) in 160 drug-resistant Mycobacterium tuberculosis clinical isolates from Thailand were analysed. Mutations in the katG gene were found in 129 isolates, predominantly at codon 315, which was mutated in 127 isolates. Twenty-two isolates had mutations in the inhA promoter and coding region. Mutations in the oxyR-ahpC intergenic region and in ndh were detected in four and one isolate(s), respectively. Of 24 ethionamide-resistant isolates, 13 had mutations in the ethA gene. However, these mutations were dispersed along the entire gene, with no codon predominating significantly.
authors.affiliation: Department of Microbiology, Faculty of Medicine Siriraj Hospital, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: S
authors.initials: S
authors.lastname: Boonaiam
authors.forename: A
authors.initials: A
authors.lastname: Chaiprasert
authors.forename: T
authors.initials: T
authors.lastname: Prammananan
authors.forename: M
authors.initials: M
authors.lastname: Leechawengwongs
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D002374:Catalase / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D005000:Ethionamide / Q000494:pharmacology*; D005838:Genotype; D007538:Isoniazid / Q000494:pharmacology*; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification; D017421:Sequence Analysis; D013785:Thailand; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis / Q000382:microbiology*
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D002374:Catalase; C480353:katG protein, Mycobacterium tuberculosis; D005000:Ethionamide; D007538:Isoniazid