Isoniazid is a first-line antibiotic used in the treatment of infections caused by Mycobacterium tuberculosis. Isoniazid is a prodrug requiring oxidative activation by the catalase-peroxidase hemoprotein, KatG. Resistance to isoniazid can be obtained by point mutations in the katG gene, with one of the most common being a threonine-for-serine substitution at position 315 (S315T). The S315T muta...

We have identified a potential quality control strain of Mycobacterium tuberculosis to monitor isoniazid susceptibility testing. This strain (strain A) has a stable phenotypic low-level resistance to isoniazid, has a mutation of C (-15) --> T in the inhA promoter region, and gave consistent susceptibility test results in 141 laboratories.

background : republic of azerbaijan is considered as an area with high prevalence of multi-drug resistant tuberculosis. uncontrolled travelling of azerbaijanis people to iran is the issue that needs to be considered as an important issue. methods : this study was conducted on 32 patients with tuberculosis from baku–nakhchivan and 48 patients from iran during 2012 to 2014. colonies of mycobacter...

We studied the presence of mutations in the whole katG gene and specific regions of the oxyR-ahpC and mabA-inhA regulatory region in 61 Mycobacterium tuberculosis isoniazid-resistant isolates. An 81-bp region of the rpoB gene was also sequenced in 17 rifampin-resistant strains. Alterations in the katG gene were detected in 55% of the isolates. Mutation in codon 315 was the most prevalent (32%)....

OBJECTIVES The reference standard methods for drug susceptibility testing (DST) of M. tuberculosis are very slow to give results, and due to the emergence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis, there is an urgent demand for new, rapid and accurate DST methods, particularly in low-income countries. The nitrate reductase assay (NRA) has been prop...

sensitivity between 89.5 and 96.9% for rifampin and 82.1 and 89.3% for isoniazid and reported specificity ranging from 86.2 to 94.3% for rifampin and from 88.0 to 95.1% for isoniazid. Early identification of pathogen susceptibility to rifampin and isoniazid using TB-biochips results in a significantly better tretment outcome because of the introduction of adequate drug therapy at the earliest s...

An oligonucleotide chip (Combichip Mycobacteria chip) detecting specific mutations in the rpoB, katG, and inhA genes of Mycobacterium tuberculosis was compared with conventional antimicrobial susceptibility results. The probes detecting drug resistance were as follows: 7 wild-type and 13 mutant probes for rifampin and 2 wild-type and 3 mutant probes for isoniazid. Target DNA of M. tuberculosis ...