Isoniazid (INH) is a pro-drug that has been extensively used to treat tuberculosis. INH is activated by the heme enzyme catalase-peroxidase (KatG), but the mechanism of the activation is poorly understood, in part because the INH binding site has not been clearly established. Here, we observed that a single-residue mutation of KatG from Synechococcus elongatus PCC7942 (SeKatG), W78F, enhances I...

background & objectives: although isoniazid is the most efficient in killing the tuberculosis bacilli, resistance to this drug also develops most readily. mutations in katg, inha and ahpc are responsible for isoniazid resistance in a large proportion of tuberculosis cases. the frequency of these mutations varies with population samples, however. this study provided the first molecular character...

BACKGROUND Accurate and rapid detection of drug-resistant Mycobacterium tuberculosis is fundamental for the successful treatment of tuberculosis (TB). OBJECTIVES The aim of this study was to determine the frequency of common mutations leading to isoniazid (INH) and rifampicin (RMP) resistance. PATIENTS AND METHODS In a cross-sectional study carried out in 2014, 90 patients with M. tuberculo...

conclusions detection of drug resistance associated with mutations through real-time pcr by melting analysis technique showed a high differentiating power. this technique had high concordance with the standard proportion test and mas-pcr results. patients and methods in a cross-sectional study carried out in 2014, 90 patients with m. tuberculosis from five border provinces of iran were selected...

Stable films of dimyristoylphosphatidylcholine and M. tuberculosis catalase-peroxidase (KatG), several peroxidases, myoglobin, and catalase showed reversible FeIII/FeII voltammetry on pyrolytic graphite electrodes and catalytic current for hydrogen peroxide and oxygen. Amperometric responses for these films to H2O2 at 0 V are likely to contain significant contributions from catalytic reduction ...

The aim of this study was to use DNA sequencing analysis to analyze the mutations in the most commonly targeted genes (katG, inhA, rpoB, rpsL) in isoniazid (INH)-, rifampin (RIF)- and streptomycin (SM)-resistant Mycobacterium tuberculosis strains obtained from subjects in Duzce, Turkey. Four isolates were found to be INH-resistant, 3 were RIF-resistant and 5 were SM-resistant, out of a total of...

Resistance to antituberculous agents is an important cause of ineffectiveness of antimicrobial therapy. The resistance of M. tuberculosis to antituberculous agents is a result of mutations in genes participating in those agent's action. The antituberculous drug--isoniazid can be activated by Mycobacterium tuberculosis either through a hydroperoxidase I/II or a superoxide-dependent oxyferrous pa...

Automated DNA sequencing was used to analyze the oxyR-ahpC region in 229 Mycobacterium tuberculosis complex isolates recently recovered from diseased humans and animals. The entire 1,221-bp region was studied in 118 isolates, and 111 other isolates were sequenced for oxyR, ahpC, or the 105-bp oxyR-ahpC intergenic region. The sample included isoniazid (INH)-susceptible and -resistant organisms i...

isoniazid, is the only antituberculous drug for which the relation between lack of virulence and acquisition of resistance was associated. inh-resistant mutants were shown to contain defective katg gene. classical studies showed that inh-resistant south indian isolates have lower virulence in guinea pigs and higher susceptibility to h2o2. it is of interest to assess the virulence in south india...

Isoniazid (INH), a front-line antituberculosis agent, is activated by mycobacterial catalase-peroxidase KatG, converting INH into bactericidal reactive species. Here we investigated the requirements and the pathway of nitric oxide (NO*) generation during oxidative activation of INH by Mycobacterium tuberculosis KatG in vitro. We also provide in vivo evidence that INH-derived NO* can inhibit key...