Fluoroquinolone resistance mechanisms in multidrug-resistant Escherichia coli isolated from extraintestinal infections in dogs

Gibson, Justine S., Cobbold, Rowland N., Kyaw-Tanner, Myat T., Heisig, Peter and Trott, Darren J. (2010) Fluoroquinolone resistance mechanisms in multidrug-resistant Escherichia coli isolated from extraintestinal infections in dogs. Veterinary Microbiology, 146 1-2: 161-166. doi:10.1016/j.vetmic.2010.04.012


Author Gibson, Justine S.
Cobbold, Rowland N.
Kyaw-Tanner, Myat T.
Heisig, Peter
Trott, Darren J.
Title Fluoroquinolone resistance mechanisms in multidrug-resistant Escherichia coli isolated from extraintestinal infections in dogs
Journal name Veterinary Microbiology   Check publisher's open access policy
ISSN 0378-1135
Publication date 2010-11-20
Year available 2010
Sub-type Article (original research)
DOI 10.1016/j.vetmic.2010.04.012
Volume 146
Issue 1-2
Start page 161
End page 166
Total pages 6
Place of publication Amsterdam, The Netherlands
Publisher Elsevier
Collection year 2011
Language eng
Abstract Fluoroquinolone resistance is an emerging problem in companion animal practice. The present study aimed to determine comparative fluoroquinolone minimum inhibitory concentrations (MICs) for enrofloxacin, marbofloxacin and pradofloxacin and identify plasmid-mediated quinolone resistance (PMQR) mechanisms in 41 multidrug-resistant (MDR) Escherichia coli isolates representing three main clonal groups (CGs) cultured from extraintestinal infections in dogs. All isolates were resistant to fluoroquinolones and the PMQR genes qnrA1, qnrB2, qnrS1 and qepA were identified in isolates from each CG. For a subset of 13 representative isolates, fluoroquinolone chromosomal resistance mechanisms were characterized. CG1 isolates had three mutations in the quinolone resistance determining region (QRDR), two in gyrA (Ser TCG-83 → Leu TTG and Asp GAC-87 → Asn AAC) and one in parC (Ser AGC-80 → Ile ATT), whilst CG2 and CG3 isolates also possessed an additional mutation in parC (Glu GAA-84 → Gly GGA) which was reflected in higher fluoroquinolone MICs compared to CG1. Organic solvent tolerance was demonstrated in 8 of the 13 isolates, and all 13 isolates demonstrated enhanced efflux on the basis of a 4-fold decrease or greater in the MIC of enrofloxacin when incubated with an efflux pump inhibitor. A mutation in acrR which can cause overexpression of the AcrAB multidrug efflux pump was detected in CG1 strains. These findings indicate that fluoroquinolone resistance in MDR E. coli isolated from extraintestinal infections in dogs is associated with a combination of target mutations in the QRDRs, transferable PMQR mechanisms and enhanced efflux. © 2010 Elsevier B.V.
Keyword Dogs
Escherichia coli
Fluoroquinolones
Multidrug-resistance
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Available online 21 April, 2010.

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Veterinary Science Publications
 
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Created: Tue, 14 Dec 2010, 08:06:33 EST by Ms Justine Gibson on behalf of School of Veterinary Science