Characterization of ndh gene of isoniazid resistant and susceptible Mycobacterlum tuberculosis isolates from Brazil

• Published in: Memórias do Instituto Oswaldo Cruz Vol. 102; no. 1; pp. 59 - 61
• Main Authors: Cardoso, R F, Cardoso, MA, Leite, CQF, Sato, D N, Mamizuka, E M, Hirata, RDC, de Mello, FF, Hirata, M H
• Format: Journal Article
• Language: English
• Published: 01.02.2007
• Subjects: Mycobacterium tuberculosis
• ISSN: 0074-0276

Resistance in Mycobacterium tuberculosis to isoniazid (INH) is caused by mutations in the catalase-peroxi-dase gene (katG), and within the inhA promoter and/or in structural gene. A small percentage ( similar to 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.