title: Norwegian patients and retail chicken meat share cephalosporin-resistant Escherichia coli and IncK/blaCMY-2resistance plasmids.
abstract: OBJECTIVE
  In 2012 and 2014 the Norwegian monitoring programme for antimicrobial resistance in the veterinary and food production sectors (NORM-VET) showed that 124 of a total of 406 samples (31%) of Norwegian retail chicken meat were contaminated with extended-spectrum cephalosporin-resistant Escherichia coli. The aim of this study was to compare selected cephalosporin-resistant E. coli from humans and poultry to determine their genetic relatedness based on whole genome sequencing (WGS).
  
  
  METHODS
  Escherichia coli representing three prevalent cephalosporin-resistant multi-locus sequence types (STs) isolated from poultry (n=17) were selected from the NORM-VET strain collections. All strains carried an IncK plasmid with a blaCMY-2gene. Clinical E. coli isolates (n=284) with AmpC-mediated resistance were collected at Norwegian microbiology laboratories from 2010 to 2014. PCR screening showed that 29 of the clinical isolates harboured both IncK and blaCMY-2. All IncK/blaCMY-2-positive isolates were analysed with WGS-based bioinformatics tools.
  
  
  RESULTS
  Analysis of single nucleotide polymorphisms (SNP) in 2.5 Mbp of shared genome sequences showed close relationship, with fewer than 15 SNP differences between five clinical isolates from urinary tract infections (UTIs) and the ST38 isolates from poultry. Furthermore, all of the 29 clinical isolates harboured IncK/blaCMY-2plasmid variants highly similar to the IncK/blaCMY-2plasmid present in the poultry isolates.
  
  
  CONCLUSIONS
  Our results provide support for the hypothesis that clonal transfer of cephalosporin-resistant E. coli from chicken meat to humans may occur, and may cause difficult-to-treat infections. Furthermore, these E. coli can be a source of AmpC-resistance plasmids for opportunistic pathogens in the human microbiota.
authors.affiliation: Domain of Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway. Electronic address: einarsverre.berg@fhi.no.
authors.forename: E S
authors.initials: ES
authors.lastname: Berg
authors.affiliation: Domain of Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: A L
authors.initials: AL
authors.lastname: Wester
authors.affiliation: Centre for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Ahrenfeldt
authors.affiliation: Department of Diagnostic Services, Norwegian Veterinary Institute, Oslo, Norway.
authors.forename: S S
authors.initials: SS
authors.lastname: Mo
authors.affiliation: Department of Diagnostic Services, Norwegian Veterinary Institute, Oslo, Norway.
authors.forename: J S
authors.initials: JS
authors.lastname: Slettemeås
authors.affiliation: Domain of Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Steinbakk
authors.affiliation: Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway; Research Group for Microbial Pharmacology and Population Biology, Department of Pharmacy, University of Tromsø - The Arctic University of Norway, Tromsø, Norway.
authors.forename: Ø
authors.initials: Ø
authors.lastname: Samuelsen
authors.affiliation: Department of Clinical Microbiology, Vestfold Hospital Trust, Tønsberg, Norway.
authors.forename: N
authors.initials: N
authors.lastname: Grude
authors.affiliation: Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway; Research Group for Host-Microbe Interactions, Faculty of Health Sciences, University of Tromsø - The Arctic University of Norway, Tromsø, Norway.
authors.forename: G S
authors.initials: GS
authors.lastname: Simonsen
authors.affiliation: Department of Medical Microbiology, Stavanger University Hospital, Stavanger, Norway.
authors.forename: I H
authors.initials: IH
authors.lastname: Løhr
authors.affiliation: Department of Clinical Microbiology and Infection Control, Akershus University Hospital, Lørenskog, Norway.
authors.forename: S B
authors.initials: SB
authors.lastname: Jørgensen
authors.affiliation: Department of Clinical Microbiology, Sørlandet Hospital, Kristiansand, Norway.
authors.forename: S
authors.initials: S
authors.lastname: Tofteland
authors.affiliation: Centre for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark.
authors.forename: O
authors.initials: O
authors.lastname: Lund
authors.affiliation: Domain of Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: U R
authors.initials: UR
authors.lastname: Dahle
authors.affiliation: Domain of Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway; Department of Diagnostic Services, Norwegian Veterinary Institute, Oslo, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Sunde
mesh_terms: D000818:Animals; D002511:Cephalosporins / Q000494:pharmacology; D002645:Chickens; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics*; D005506:Food Contamination / Q000032:analysis; D006801:Humans; D009664:Norway; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics; D020641:Polymorphism, Single Nucleotide; D011202:Poultry Products / Q000382:microbiology*; D014552:Urinary Tract Infections / Q000382:microbiology*; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D002511:Cephalosporins; D029968:Escherichia coli Proteins; D001618:beta-Lactamases; C000605810:beta-lactamase CMY-2, E coli
keywords: Chicken meat; Plasmid-mediated AmpC transmission; Urinary tract infections; Zoonotic transfer of cephalosporin-resistant Escherichia coli