title: Characterization of multiple and extensively drug resistant Mycobacterium tuberculosis isolates with different ofloxacin-resistance levels.
abstract: The goal of the study was to determine different mutation types in gyrA and gyrB genes in Mycobacterium tuberculosis strains with low-level (2 μg/ml) and high-level (10 μg/ml) ofloxacin (OFL) resistance and to compare genetic diversity of ofloxacin-resistant and susceptible M. tuberculosis isolates. M. tuberculosis isolates were collected in Leningrad Region in 2011. DNA sequencing showed that 54.3% of isolates with low-level and 76.9% of isolates with high-level OFL-resistance had mutations in gyrA gene. Few isolates carried mutations in gyrB gene - five among isolates with low-level resistance and two among high-level resistant isolates. Altogether, detection of point mutations in both DNA gyrase genes allows to identify 66.9% of mycobacterial isolates with low-level and 84.5% of isolates with high-level of OFL-resistance. Novel mutations S91L in gyrA gene and S512L in gyrB gene described in this study were detected in OFL-resistant isolates and may play role in M. tuberculosis fluoroquinolone resistance. M. tuberculosis Beijing family spoligotypes were identified among 70.8% of isolates with low-level resistance, 84.6% of isolates with high-level resistance and 50% of strains susceptible to all tuberculosis drugs. Fisher's exact test revealed significant difference between Beijing prevalence in groups of drug-susceptible or high-level OFL-resistant M. tuberculosis strains (p-value = 0.032).
authors.affiliation: Biomedical Center, St. Petersburg, Russia. echernya@gmail.com
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Chernyaeva
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Fedorova
authors.forename: Galina
authors.initials: G
authors.lastname: Zhemkova
authors.forename: Yuriy
authors.initials: Y
authors.lastname: Korneev
authors.forename: Andrei
authors.initials: A
authors.lastname: Kozlov
mesh_terms: D019943:Amino Acid Substitution; D000995:Antitubercular Agents / Q000008:administration & dosage / Q000494:pharmacology*; D027081:DNA Gyrase / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D054908:Extensively Drug-Resistant Tuberculosis / Q000382:microbiology*; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000145:classification / Q000187:drug effects* / Q000235:genetics*; D015242:Ofloxacin / Q000008:administration & dosage / Q000494:pharmacology*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D014397:Tuberculosis, Pulmonary / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D015242:Ofloxacin; D027081:DNA Gyrase