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

Gibson, Justine S., Cobbold, Rowland N., Heisig, Peter, Sidjabat, Hanna E., Kyaw-Tanner, Myat T. and Trott, Darren J. (2010) 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, 143 2-4: 329-336. doi:10.1016/j.vetmic.2009.11.031


Author Gibson, Justine S.
Cobbold, Rowland N.
Heisig, Peter
Sidjabat, Hanna E.
Kyaw-Tanner, Myat T.
Trott, Darren J.
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
Formatted 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
Journal name Veterinary Microbiology   Check publisher's open access policy
ISSN 0378-1135
1873-2542
Publication date 2010-07-14
Year available 2009
Sub-type Article (original research)
DOI 10.1016/j.vetmic.2009.11.031
Volume 143
Issue 2-4
Start page 329
End page 336
Total pages 8
Editor W. Gaastra
U. Truyen
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Collection year 2011
Language eng
Formatted 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 blaSHV-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.
© 2009 Elsevier B.V.
Keyword Enterobacter
Multidrug resistance
Plasmids
Fluoroquinolones
Companion animals
Quinolone resistance
Escherichia-coli
Modifying enzyme
United-states
Gene
Prevalence
Cloacae
Salmonella
Expression
Mutations
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Available online 3 December 2009

Document type: Journal Article
Sub-type: Article (original research)
Collections: UQ Centre for Clinical Research Publications
Official 2011 Collection
School of Veterinary Science Publications
 
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Citation counts: TR Web of Science Citation Count  Cited 17 times in Thomson Reuters Web of Science Article | Citations
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Created: Sun, 11 Jul 2010, 00:00:33 EST