The mechanisms of resistance to levofloxacin for Aeromonas hydrophila isolated from diseased fish and selected in vitro were examined in this study. Levofloxacin-resistant mutants were obtained by selection of A. hydrophila in vitro. The quinolone resistance-determining regions (QRDRs) of the gyrA and parC genes were sequenced in Lev(R) strains and reverse mutation strains. All Lev(R) strains carried a point mutation at codon 83 (Ser → Ile), and one strain (25 %) harbored a mutation at position 92 (Leu → Met) in the GyrA-QRDR. After being transferred in a levofloxacin-free medium, one strain of the mutants was successfully reversed and the reversion was related with mutations of GyrA-QRDR at positions 81 (Gly → Asp) and 83 (Ile → Ser). No amino acid alteration was found in the ParC-QRDR. In addition, the minimum inhibitory concentration (MIC) of levofloxacin for the mutants was lower in the presence of reserpine, and all mutants were also resistant to some of the other quinolones. It was found that the mechanism of levofloxacin resistance of A. hydrophila selected in vitro was related to gyrA of type II topoisomerase, and an efflux mechanism was involved in the resistance as well.
- MeSH
- Aeromonas hydrophila účinky léků enzymologie genetika MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální léková rezistence * MeSH
- DNA-topoisomerasy typu II genetika metabolismus MeSH
- levofloxacin farmakologie MeSH
- mikrobiální testy citlivosti MeSH
- mutace MeSH
- ryby mikrobiologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Out of the twenty-one A. hydrophila complex isolates obtained during a routine examination of human diarrhoeal faeces, two A. hydrophila subsp. dhakensis isolates (P1097 = CCM 7329 and P1165) were successfully identified by ribotyping. The correct taxonomic position of the A. hydrophila subsp. dhakensis CCM 7329 was verified by cpn60 sequencing (GeneBank accession number HM536193). The remaining A. hydrophila complex isolates were identified as A. hydrophila subsp. hydrophila. The ability of biochemical tests and fatty acid methyl ester analysis to reliably discern both A. hydrophila subsp. dhakensis and A. hydrophila subsp. hydrophila was limited. In contrast to the A. hydrophila subsp. hydrophila, the faecal isolates of A. hydrophila subsp. dhakensis did not produce acid from arbutin. When compared in a two-dimensional plot, the A. hydrophila subsp. dhakensis faecal isolates contained higher amounts of the two minor fatty acids C(13:0) and C(17:1) ω8c than the A. hydrophila subsp. hydrophila reference strain. This is the first detected occurrence of the less frequent A. hydrophila subsp. dhakensis in our region and ribotyping was proved as a suitable method for the identification of A. hydrophila subsp. dhakensis.
- MeSH
- Aeromonas hydrophila klasifikace genetika izolace a purifikace MeSH
- bakteriální proteiny genetika MeSH
- chaperonin 10 genetika MeSH
- feces mikrobiologie MeSH
- fenotyp MeSH
- fylogeneze MeSH
- gramnegativní bakteriální infekce epidemiologie mikrobiologie MeSH
- lidé MeSH
- mastné kyseliny analýza MeSH
- molekulární sekvence - údaje MeSH
- polymerázová řetězová reakce MeSH
- průjem epidemiologie mikrobiologie MeSH
- ribotypizace MeSH
- sekvenční analýza DNA MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
