title: Characterization of ndh gene of isoniazid resistant and susceptible Mycobacterium tuberculosis isolates from Brazil.
abstract: Resistance in Mycobacterium tuberculosis to isoniazid (INH) is caused by mutations in the catalase-peroxidase gene (katG), and within the inhA promoter and/or in structural gene. A small percentage (approximately 10%) of INH-resistant strains do not present mutations in both of these loci. Other genes have been associated with INH resistance including the gene encoding for NADH dehydrogenase (ndh). Here we report the detection of two ndh locus mutations (CGT to TGT change in codon 13 and GTG to GCG change in codon 18) by analyzing 23 INH-resistant and in none of 13 susceptible isolates from Brazilian tuberculosis patients. We also detected two isolates without a mutation in ndh, or any of the other INH resistance-associated loci examined, suggesting the existence of additional, as yet to be described, INH resistance mechanisms.
authors.affiliation: Laborartório de Bacteriologia Clínica, Departamento de Análises Clínicas, Universidade Estadual de Maringá, Brasil. rfcardoso@uem.br
authors.forename: Rosilene Fressatti
authors.initials: RF
authors.lastname: Cardoso
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Cardoso
authors.forename: Clarice Queico Fujimura
authors.initials: CQ
authors.lastname: Leite
authors.forename: Daisy Nakamura
authors.initials: DN
authors.lastname: Sato
authors.forename: Elsa Masae
authors.initials: EM
authors.lastname: Mamizuka
authors.forename: Rosário Dominguez Crespo
authors.initials: RD
authors.lastname: Hirata
authors.forename: Fernando Fiúza
authors.initials: FF
authors.lastname: de Mello
authors.forename: Mario Hiroyuki
authors.initials: MH
authors.lastname: Hirata
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D001938:Brazil; D024881:Drug Resistance, Bacterial / Q000235:genetics; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009154:Mutation / Q000235:genetics*; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D009245:NADH Dehydrogenase / Q000235:genetics*; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational
chemical_list: D000995:Antitubercular Agents; D009245:NADH Dehydrogenase; D007538:Isoniazid