title: Occurrence and characterization of mcr-1-harbouring Escherichia coli isolated from pigs in Great Britain from 2013 to 2015.
abstract: To determine the occurrence of mcr-1 -harbouring Escherichia coli in archived pig material originating in Great Britain (GB) from 2013 to 2015 and characterize mcr-1 plasmids.
  
  
  
  Enrichment and selective culture of 387 archived porcine caecal contents and recovery from archive of 1109 E. coli isolates to identify colistin-resistant bacteria by testing for the presence of mcr-1 by PCR and RT-PCR. mcr-1 -harbouring E. coli were characterized by WGS and compared with other available mcr-1 WGS.
  
  
  
  Using selective isolation following enrichment, the occurrence of mcr-1 E. coli in caeca from healthy pigs at slaughter from unique farms in GB was 0.6% (95% CI 0%-1.5%) in 2015. mcr-1 E. coli were also detected in isolates from two porcine veterinary diagnostic submissions in 2015. All isolates prior to 2015 were negative. WGS analysis of the four mcr-1 -positive E. coli indicated no other antimicrobial resistance (AMR) genes were linked to mcr-1 -plasmid-bearing contigs, despite all harbouring multiple AMR genes. The sequence similarity between mcr-1 -plasmid-bearing contigs identified and those found in GB, Chinese and South African human isolates and Danish, French and Estonian livestock-associated isolates was 90%-99%.
  
  
  
  mcr-1- harbouring plasmids were diverse, implying transposable elements are involved in mcr-1 transmission in GB. The low number of mcr-1 -positive E. coli isolates identified suggested mcr-1 is currently uncommon in E. coli from pigs within GB. The high sequence similarity between mcr-1 plasmid draft genomes identified in pig E. coli and plasmids found in human and livestock-associated isolates globally requires further investigation to understand the full implications.
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Duggett
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.|Department of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU2 7XH, UK.
authors.forename: Ellie
authors.initials: E
authors.lastname: Sayers
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Manal
authors.initials: M
authors.lastname: AbuOun
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Ellis
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Javier
authors.initials: J
authors.lastname: Nunez-Garcia
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Luke
authors.initials: L
authors.lastname: Randall
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Horton
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Jon
authors.initials: J
authors.lastname: Rogers
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Francesca
authors.initials: F
authors.lastname: Martelli
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Smith
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Camilla
authors.initials: C
authors.lastname: Brena
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Susanna
authors.initials: S
authors.lastname: Williamson
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Miranda
authors.initials: M
authors.lastname: Kirchner
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Davies
authors.affiliation: Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford University, Oxford OX3 7BN, UK.
authors.forename: Derrick
authors.initials: D
authors.lastname: Crook
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Evans
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Teale
authors.affiliation: Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK.
authors.forename: Muna F
authors.initials: MF
authors.lastname: Anjum
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004251:DNA Transposable Elements / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000235:genetics*; D005243:Feces / Q000382:microbiology; D006801:Humans; D058751:Livestock / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D010957:Plasmids; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology / Q000635:transmission*; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D029968:Escherichia coli Proteins; C000614037:MCR-1 protein, E coli