title: [Role of mutations in parC and gyrA in forming resistance of Mycoplasma hominis to fluoroquinolones].
abstract: The set of the laboratory strain M. hominis H-34 mutants resistant to fluoroquinolones (ciprofloxacin-Cfl, lomefloxacin-Lfl, ofloxacin-Ofl) was obtained by selection in broth medium. The mutation was found in the quinolone resistance-determining region (QRDR) of A subunit of topoisomerase IV gene (parC) and new mutations were found in QRDR of genes encoding the A subunit of DNA gyrase (gyrA) in M. hominis mutants resistant to various concentrations of the Cfl, Lfl and Ofl. After multistep selection of the obtained mutants at constant concentrations of Cfl additional mutation Ser83 to Trp was revealed. No mutations in parE and gyrB were found. Mutations in parC for laboratory strain M. hominis H34 appeared at lower antibiotic concentrations than in gyrA. All mutations in gyr A were associated with mutations in parC. This confirms the previous data that topoisomerase IV is the primary target of Cfl and Ofl and suggests that it is the primary target of Lfl. Some M. hominis mutants selected at Ofl without any substitution in QRDRs were shown to be insensitive to Cfl and of Lfl. Studies of cross-resistance of the selected M. hominis mutants showed that their resistance to various fluoroquinolone concentrations could not depend on any mutations in QRDR of topoisomerase IV and DNA gyrase genes and suggests involvement of other unknown molecular mechanisms specific for Mycoplasmas.
authors.forename: A E
authors.initials: AE
authors.lastname: Gushchin
authors.forename: V G
authors.initials: VG
authors.lastname: Ladygina
authors.forename: V M
authors.initials: VM
authors.lastname: Govorun
mesh_terms: D019943:Amino Acid Substitution; D000890:Anti-Infective Agents / Q000494:pharmacology*; D027081:DNA Gyrase; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II / Q000235:genetics*; D004352:Drug Resistance, Microbial / Q000235:genetics; D024841:Fluoroquinolones; D009154:Mutation; D019535:Mycoplasma hominis / Q000187:drug effects* / Q000235:genetics
chemical_list: D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II