title: Molecular characteristics of rifampin- and isoniazid-resistant mycobacterium tuberculosis strains isolated in Vietnam.
abstract: Molecular characterization of the drug resistance of Mycobacterium tuberculosis strains with different origins can generate information that is useful for developing molecular methods. These methods are widely applicable for rapid detection of drug resistance. A total of 166 rifampin (RIF)- and/or isoniazid (INH)-resistant strains of M. tuberculosis have been isolated from different parts of Vietnam; they were screened for mutations associated with resistance to these drugs by sequence analysis investigating genetic mutations associated with RIF and INH resistance. Seventeen different mutations were identified in 74 RIF-resistant strains, 56 of which (approximately 76%) had mutations in the so-called 81-bp "hot-spot" region of the rpoB gene. The most common point mutations were in codons 531 (37.8%), 526 (23%), and 516 (9.46%) of the rpoB gene. Mutations were not found in three strains (4.05%). In the case of INH resistance, five different mutations in the katG genes of 82 resistant strains were detected, among which the nucleotide substitution at codon 315 (76.83%) is the most common mutation. This study provided the first molecular characterization of INH and RIF resistance of M. tuberculosis strains from Vietnam, and detection of the katG and rpoB mutations of the INH and RIF-resistant strains should be useful for rapid detection of the INH- and RIF-resistant strains by molecular tests.
authors.affiliation: Institute of Biotechnology, Vietnam Academy of Science and Technology, Hospital 103, Vietnam Military Medical University, Vietnam. nghiemminh@ibt.ac.vn
authors.forename: Nghiem Ngoc
authors.initials: NN
authors.lastname: Minh
authors.forename: Nguyen
authors.initials: N
authors.lastname: Van Bac
authors.forename: Nguyen Thai
authors.initials: NT
authors.lastname: Son
authors.forename: Vu Thi Kim
authors.initials: VT
authors.lastname: Lien
authors.forename: Chu Hoang
authors.initials: CH
authors.lastname: Ha
authors.forename: Nguyen Huu
authors.initials: NH
authors.lastname: Cuong
authors.forename: Cung Thi Ngoc
authors.initials: CT
authors.lastname: Mai
authors.forename: Thanh Hoa
authors.initials: TH
authors.lastname: Le
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D002374:Catalase / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D024881:Drug Resistance, Bacterial; D005838:Genotype; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology*; D058889:Molecular Typing; D050505:Mutant Proteins / Q000235:genetics; D020125:Mutation, Missense; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D012293:Rifampin / Q000494:pharmacology*; D018088:Tuberculosis, Multidrug-Resistant / Q000382:microbiology*; D014744:Vietnam
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D050505:Mutant Proteins; D002374:Catalase; C480353:katG protein, Mycobacterium tuberculosis; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit; D007538:Isoniazid; D012293:Rifampin