Mechanisms of Reduced Susceptibility to Ciprofloxacin in Escherichia coli Isolates from Canadian Hospitals

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dc.contributor.authorBaudry-Simner, Patricia J
dc.contributor.authorSingh, Amanpreet
dc.contributor.authorKarlowsky, James A
dc.contributor.authorHoban, Daryl J
dc.contributor.authorZhanel, George G
dc.contributor.authorCanadian Antimicrobial Resistance Alliance,
dc.date.accessioned2016-05-31T17:11:14Z
dc.date.available2016-05-31T17:11:14Z
dc.date.issued2012-1-1
dc.date.updated2016-05-09T08:46:46Z
dc.description.abstractOBJECTIVE: To determine whether plasmid-mediated quinolone resistance (PMQR) determinants play a role in the increasing resistance to fluoroquinolones among Escherichia coli isolates in Canadian hospitals, and to determine the mechanisms of reduced susceptibility to ciprofloxacin in a recent collection of 190 clinical E coli isolates.METHODS: E coli isolates (n=1702) were collected as part of the 2007 Canadian Hospital Ward Antibiotic Resistance Surveillance (CANWARD) study. Antimicrobial susceptibility testing was performed by Clinical and Laboratory Standards Institute (CLSI) broth microdilution. Using a representative subset of isolates (n=190), the mechanisms of reduced susceptibility to ciprofloxacin were detected by polymerase chain reaction and sequencing of the quinolone resistance-determining regions (QRDR) of chromosomal gyrA and parC genes, and by polymerase chain reaction for the PMQR genes: qnr, aac(6′) Ib-cr and qepA.RESULTS: 2.1% and 1.1% of E coli harboured aac(6′)Ib-cr and qnrB, respectively. Single amino acid substitutions in the QRDR of gyrA were observed among isolates with ciprofloxacin minimum inhibitory concentrations as low as 0.12 μg/mL. As the ciprofloxacin minimum inhibitory concentration increased to 1 μg/mL (which is still considered to be susceptible by the CLSI), the vast majority of isolates demonstrated both gyrA and parC mutations.CONCLUSION: PMQR determinants and QRDR mutants among clinical E coli isolates with reduced susceptibility to ciprofloxacin demonstrates the need for increased surveillance and the need to re-evaluate the current CLSI breakpoints to prevent further development of fluoroquinolone resistance.
dc.description.versionPeer Reviewed
dc.identifier.citationPatricia J Baudry-Simner, Amanpreet Singh, James A Karlowsky, Daryl J Hoban, George G Zhanel, and Canadian Antimicrobial Resistance Alliance, “Mechanisms of Reduced Susceptibility to Ciprofloxacin in Escherichia coli Isolates from Canadian Hospitals,” Canadian Journal of Infectious Diseases and Medical Microbiology, vol. 23, no. 3, pp. e60-e64, 2012. doi:10.1155/2012/569093
dc.identifier.urihttp://dx.doi.org/10.1155/2012/569093
dc.identifier.urihttp://hdl.handle.net/1993/31308
dc.language.rfc3066en
dc.rightsopen accessen_US
dc.rights.holderCopyright © 2012 Hindawi Publishing Corporation. This open-access article is distributed under the terms of the Creative Commons Attribution Non-Commercial License (CC BY-NC) (http://creativecommons.org/licenses/by-nc/4.0/), which permits reuse, distribution and reproduction of the article, provided that the original work is properly cited and the reuse is restricted to noncommercial purposes.
dc.titleMechanisms of Reduced Susceptibility to Ciprofloxacin in Escherichia coli Isolates from Canadian Hospitals
dc.typeJournal Article
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