Journal article
Identification of Qnr and AAC(6′)-1b-cr plasmid-mediated fluoroquinolone resistance determinants in multidrug-resistant Enterobacter spp. isolated from extraintestinal infections in companion animals
Veterinary microbiology, Vol.143(2), pp.329-336
2010
Handle:
https://hdl.handle.net/2376/105736
PMID: 20036084
Abstract
Fluoroquinolone resistance is becoming more common in veterinary medicine. Resistance is due to a combination of chromosomal and plasmid-mediated fluoroquinolone resistance (PMQR) mechanisms. The aim of the present study was to screen 17 multidrug-resistant
Enterobacter isolates obtained from opportunistic infections in companion animals for chromosomal and plasmid-mediated fluoroquinolone resistance determinants and to determine if they are co-located with other antimicrobial resistance genes including β-lactamases.
Phenotypic tests (biochemical identification, organic solvent tolerance testing) were combined with genotypic analysis (PCR, pulsed field gel electrophoresis, sequencing, plasmid isolation and southern blot hybridization) to characterize the molecular basis for fluoroquinolone resistance. Antimicrobial susceptibility was determined by broth microdilution for fluoroquinolone antimicrobials (enrofloxacin, ciprofloxacin, moxifloxacin, marbofloxacin and pradofloxacin) and by disk diffusion for other antimicrobials.
Sixteen isolates were resistant to at least one of the five fluoroquinolones tested. Fourteen isolates possessed PMQR determinants which were identified as
qnrA1 (
n
=
3) or
qnrB2 (
n
=
11), often in combination with
aac(6′
)-1b-cr (
n
=
6). The PMQR genes were localized to large, transferable MDR plasmids often associated with an extended-spectrum β-lactamase and quinolone resistance was co-transferred with
bla
SHV-12 for 10 of the 14
qnr-positive strains. Three isolates had wild-type topoisomerases, 11 had a single point mutation in
gyrA (Ser83Phe or Tyr), and three had two mutations; one in
gyrA (Ser83Ile) and one in
parC (Ser80Ile).
PMQR genes in clinical veterinary
Enterobacter isolates are co-located with β-lactamases and other resistance genes on large transferable plasmids. PMQR genes contribute to fluoroquinolone resistance when combined with topoisomerase mutations and efflux.
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Details
- Title
- Identification of Qnr and AAC(6′)-1b-cr plasmid-mediated fluoroquinolone resistance determinants in multidrug-resistant Enterobacter spp. isolated from extraintestinal infections in companion animals
- Creators
- Justine S Gibson - The University of Queensland, School of Veterinary Science, Seddon Building, Slip Road, St Lucia, Brisbane, Qld 4072, AustraliaRowland N Cobbold - The University of Queensland, School of Veterinary Science, Seddon Building, Slip Road, St Lucia, Brisbane, Qld 4072, AustraliaPeter Heisig - University of Hamburg, Chemistry Department, School of Pharmacy, Pharmaceutical Biology and Microbiology, Bundesstraße 45, D-20146 Hamburg, GermanyHanna E Sidjabat - The University of Queensland, Centre for Clinical Research, Herston, Qld 4029, AustraliaMyat T Kyaw-Tanner - The University of Queensland, School of Veterinary Science, Seddon Building, Slip Road, St Lucia, Brisbane, Qld 4072, AustraliaDarren J Trott - The University of Queensland, School of Veterinary Science, Seddon Building, Slip Road, St Lucia, Brisbane, Qld 4072, Australia
- Publication Details
- Veterinary microbiology, Vol.143(2), pp.329-336
- Publisher
- Elsevier B.V
- Identifiers
- 99900546569401842
- Language
- English
- Resource Type
- Journal article