2. Molecular testing based on katG and rpoB enabled rapid detection of Mycobacterium tuberculosis resistance in 46.8% and 87.5% of patients infected with isoniazidand rifampicinresistant strains, respectively. The same number of patients infected with resistant strains with mutations in katG and rpoB were detected using the MTBDRplus line probe assay. The combined use of katG and inhA regulator...

The prevalence of mutations at amino acid (aa) position 315 in the katG gene of isoniazid (INH)-resistant Mycobacterium tuberculosis isolates in The Netherlands and the mutation's association with the level of INH resistance, multidrug resistance, and transmission were determined. Of 4288 M. tuberculosis isolates with available laboratory results, 295 (7%) exhibited INH resistance. Of 148 aa 31...

Isoniazid (INH) activation in vitro is associated with reduction of the mycobacterial ferric KatG catalase-peroxidase by hydrazine and reaction with O2 to form an oxyferrous enzyme complex. Since this complex could also form directly via reaction of ferric KatG with superoxide, intracellular activation might be responsive to superoxide concentration. When Mycobacterium smegmatis carrying the M....

OBJECTIVES Multidrug-resistant tuberculosis (MDR-TB) is a global problem that many countries are challenged with. Rapid and accurate detection of MDR-TB is critical for appropriate treatment and controlling of TB. The aim of the present study was to evaluate the TaqMan allelic discrimination without minor groove binder (MGB) as a rapid, efficient, and low-cost method for detection of drug resis...

Francisella tularensis is a facultative intracellular bacterium utilizing macrophages as its primary intracellular habitat and is therefore highly capable of resisting the effects of reactive oxygen species (ROS), potent mediators of the bactericidal activity of macrophages. We investigated the roles of enzymes presumed to be important for protection against ROS. Four mutants of the highly viru...

In this study, a battery of oligonucleotides was directed toward the katG gene and PCR-single-stranded conformation polymorphism (SSCP) analysis was used to search for katG gene deviations in clinical isolates of Mycobacterium tuberculosis from different geographical regions. Since a complete deletion of the katG gene was not found, it is suggested that deletion is not a major mechanism of ison...

Recently, it was demonstrated that bifunctional catalase-peroxidases (KatGs) are found not only in archaea and bacteria but also in lower eukaryotes. Structural studies and preliminary biochemical data of the secreted KatG from the rice pathogen Magnaporthe grisea (MagKatG2) suggested both similar and novel features when compared to those of the prokaryotic counterparts studied so far. In this ...

Mutation at codon 315 of katG gene is the major cause for isoniazid (INH) resistance in Mycobacterium tuberculosis (M. tuberculosis). Substitution at codon 315 of katG gene was analyzed in 85 phenotypically resistant isolates collected from various parts of southern India by direct sequencing method. The obtained results were interpreted in the context of minimum inhibitory concentration (MIC) ...

It has long been known that almost all isoniazid (INH) resistant mycobacteria lose the catalase and peroxidase activities along with reduced or no virulence for guinea pigs. Recently resistance to INH has become known to be associated with mutations of katG gene encoding the HPI (Hydroperoxidase I) type catalase and peroxidase. Among these mutations, the point mutation of codon 463 of katG gene...

In a previous study, katE complementation of an E. coli katG mutant suggested that an overexpression of katE was the cause for low survival after UV-A treatment. In this study, when JW strains lacked either katE or katG were complemented with katE, this overexpression was not observed. Rather, there were no differences between the two complemented JW strains after UV-A treatment. A possible the...