Characterization of ndh gene of isoniazid resistant and susceptible Mycobacterium tuberculosis isolates from Brazil.
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.
Cardoso
Rosilene Fressatti
RF
Laborartório de Bacteriologia Clínica, Departamento de Análises Clínicas, Universidade Estadual de Maringá, Brasil. rfcardoso@uem.br
Cardoso
Marco Antonio
MA
Leite
Clarice Queico Fujimura
CQ
Sato
Daisy Nakamura
DN
Mamizuka
Elsa Masae
EM
Hirata
Rosário Dominguez Crespo
RD
de Mello
Fernando Fiúza
FF
Hirata
Mario Hiroyuki
MH
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
D000995:Antitubercular Agents; D009245:NADH Dehydrogenase; D007538:Isoniazid