Transmission Electron Microscopy of XDR Mycobacterium tuberculosis Isolates Grown on High Dose of Ofloxacin.

The aim of the study was to investigate behavior of resistant Mycobacterium tuberculosis (MTB) isolates under a high dose of ofloxacin and its morphological changes. 19 extensively drug resistant (XDR) clinical isolates of MTB were grown on Löwenstein-Jensen medium containing progressively increasing concentrations of ofloxacin (2, 4, 8, 16, 32 mg/L). Ultra-structure analyses of resistant isolates grown on ofloxacin were conducted by transmission electron microscopy (TEM).

Molecular detection of fluoroquinolone resistance-associated gyrA mutations in ofloxacin-resistant clinical isolates of Mycobacterium tuberculosis from Iran and Belarus.

Objective/background: Detection of mutations in the quinolone resistance-determining region (QRDR) of the gyrA gene could determine resistance to fluoroquinolone antituberculosis drugs. The aim of this study was to detect mutations in QRDRs.

Methods: From 184 clinical isolates of Mycobacterium tuberculosis, ofloxacin resistance was proven in 42 isolates using the proportion method.

Determination of principal genotypic groups among susceptible, MDR and XDR clinical isolates of Mycobacterium tuberculosis in Belarus and Iran.

Introduction: All members of the Mycobacterium tuberculosis complex were assigned to one of the three principle genetic groups based on KatG463/GyrA95 polymorphism.

Materials And Methods: A total of 202 isolates of M. tuberculosis consisting of 50 susceptible, 121 MDR (multidrug resistant) and 31 XDR (extensively drug resistant) isolated from culture-confirmed tuberculosis patients in different regions of Belarus and Iran (Tehran and Markazi province).

A study on demographic characteristics of drug resistant Mycobacterium tuberculosis isolates in Belarus.

Objective: A descriptive study of drug-resistance patterns by age group and among culture-positive pulmonary tuberculosis (TB) patients referred to the Research Institute for Pulmonology and Phthisiology of Belarus between January 2007 and January 2008.

Methods: Drug susceptibility tests were performed for first- and second-line anti-tuberculosis drugs. Patients were clustered into five resistance categories: mono-resistant (Mono); multi-drug resistant (MDR); all first-line drug resistance (MDR+ES); and extensively drug resistant (XDR).

Study of promoter and structural gene sequence of whiB7 in MDR and XDR forms of Mycobacterium tuberculosis.

Resistance phenomenon in M tuberculosis is mainly based on decreased permeability of the bacterial envelope and function of effluent pumps. The regulatory gene of the whiB7 transcription determines drug resistance in these bacteria. Increases in WhiB7 protein activity induce transcription of resistance genes leading to intrinsic multidrug resistance.