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dc.contributor.author
Dona, Valentina
dc.contributor.author
Scheidegger, Maximilian
dc.contributor.author
Pires, Joao
dc.contributor.author
Furrer, Hansjakob
dc.contributor.author
Atkinson, Andrew
dc.contributor.author
Flury, Baharak B.
dc.date.accessioned
2019-06-26T08:09:25Z
dc.date.available
2019-06-26T07:09:59Z
dc.date.available
2019-06-26T08:01:07Z
dc.date.available
2019-06-26T08:09:25Z
dc.date.issued
2019-06-12
dc.identifier.other
10.3389/fmicb.2019.01311
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/349773
dc.identifier.doi
10.3929/ethz-b-000349773
dc.description.abstract
Background: In a previous report, a clinical ST131 Escherichia coli isolate (Ec-1),producing a plasmid-encoded AmpC β-lactamase CMY-2, evolved in vivo under cefepime (FEP) treatment to the FEP-resistant Ec-2 strain expressing an extended-spectrum β-lactamase CMY-33. To compare factors responsible for in vitro and in vivo FEP resistance, we reproduced in vitro FEP resistance evolution in Ec-1. Methods: FEP-resistant mutants were generated by subjecting Ec-1 (FEP MIC = 0.125 mg/L) to sub-inhibitory concentrations of FEP. MICs were obtained by broth microdilution or Etest. Strains were sequenced on an Illumina HiSeq platform. Transcriptional levels and plasmid copy numbers were determined by real-time PCR. Outer membrane proteins (OMPs) were extracted and separated by SDS-PAGE. Growth kinetics was evaluated by measuring OD450. Results: The CMY-2 expressed by Ec-1 evolved to a CMY-69 (strain EC-4) by an Ala294Pro substitution after 24 passages. After 30 passages, the FEP MIC increased to 256 mg/L (strain EC-32). SDS PAGE did not reveal any lack of OMPs in the mutant strains. However, blaCMY transcription levels were up to 14-times higher than in Ec-1, which was partially explained by mutations in the upstream region of repA resulting in a higher copy number of the blaCMY-harboring IncI1 plasmid. All mutants showed a slight growth defect but no significant difference in relative growth rates compared to Ec-1. Conclusion: In vitro sub-inhibitory concentrations of FEP resulted in the selection of resistance mutations altering the H-10 helix of the CMY-2 and increasing the plasmid copy number. Appropriate dosing strategies may help preventing resistance evolution during treatments.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
Frontiers Research Foundation
en_US
dc.rights.uri
http://creativecommons.org/licenses/by/4.0/
dc.subject
CMY-2
en_US
dc.subject
CMY-69
en_US
dc.subject
WGS
en_US
dc.subject
resistance evolution
en_US
dc.subject
ST131
en_US
dc.subject
cefepime
en_US
dc.title
Gradual in vitro Evolution of Cefepime Resistance in an ST131 Escherichia coli Strain Expressing a Plasmid-Encoded CMY-2 beta-Lactamase
en_US
dc.type
Conference Paper
dc.rights.license
Creative Commons Attribution 4.0 International
ethz.journal.title
Frontiers in Microbiology
ethz.journal.volume
10
en_US
ethz.pages.start
1311
en_US
ethz.size
8 p.
en_US
ethz.version.deposit
publishedVersion
en_US
ethz.event
28th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID 2018)
en_US
ethz.event.location
Madrid, Spain
en_US
ethz.event.date
April 21-24, 2018
en_US
ethz.identifier.wos
ethz.publication.place
Lausanne
en_US
ethz.publication.status
published
en_US
ethz.date.deposited
2019-06-26T07:10:02Z
ethz.source
WOS
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2019-06-26T08:01:18Z
ethz.rosetta.lastUpdated
2020-02-15T19:50:46Z
ethz.rosetta.exportRequired
true
ethz.rosetta.versionExported
true
ethz.COinS
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