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Storey N, Cawthraw S, Turner O, Rambaldi M, Lemma F, Horton R, Randall L, Duggett NA, AbuOun M, Martelli F, Anjum MF. Use of genomics to explore AMR persistence in an outdoor pig farm with low antimicrobial usage. Microb Genom 2022; 8:000782. [PMID: 35344479 PMCID: PMC9176276 DOI: 10.1099/mgen.0.000782] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Food animals may be reservoirs of antimicrobial resistance (AMR) passing through the food chain, but little is known about AMR prevalence in bacteria when selective pressure from antimicrobials is low or absent. We monitored antimicrobial-resistant Escherichia coli over 1 year in a UK outdoor pig farm with low antimicrobial usage (AMU) compared to conventional pig farms in the United Kingdom. Short and selected long-read whole-genome sequencing (WGS) was performed to identify AMR genes, phylogeny and mobile elements in 385 E. coli isolates purified mainly from pig and some seagull faeces. Generally, low levels of antimicrobial-resistant E. coli were present, probably due to low AMU. Those present were likely to be multi-drug resistant (MDR) and belonging to particular Sequence Types (STs) such as ST744, ST88 or ST44, with shared clones (<14 Single Nucleotide Polymorphisms (SNPs) apart) isolated from different time points indicating epidemiological linkage within pigs of different ages, and between pig and the wild bird faeces. Although importance of horizontal transmission of AMR is well established, there was limited evidence of plasmid-mediated dissemination between different STs. Non-conjugable MDR plasmids or large AMR gene-bearing transposons were stably integrated within the chromosome and remained associated with particular STs/clones over the time period sampled. Heavy metal resistance genes were also detected within some genetic elements. This study highlights that although low levels of antimicrobial-resistant E. coli correlates with low AMU, a basal level of MDR E. coli can still persist on farm potentially due to transmission and recycling of particular clones within different pig groups. Environmental factors such as wild birds and heavy metal contaminants may also play important roles in the recycling and dissemination, and hence enabling persistence of MDR E. coli. All such factors need to be considered as any rise in AMU on low usage farms, could in future, result in a significant increase in their AMR burden.
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Affiliation(s)
- Nathaniel Storey
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
- Great Ormond Street Hospital for Children, London WC1N 3JH, UK
| | - Shaun Cawthraw
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Olivia Turner
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Margherita Rambaldi
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
- University of Bologna, Via Zamboni, 33, 40126 Bologna BO, Italy
| | - Fabrizio Lemma
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Robert Horton
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Luke Randall
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Nicholas A. Duggett
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
- Teeside University, Campus Heart, Middlesbrough TS1 3BX, UK
| | - Manal AbuOun
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Francesca Martelli
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Muna F. Anjum
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
- *Correspondence: Muna F. Anjum,
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Bortolaia V, Kaas RS, Ruppe E, Roberts MC, Schwarz S, Cattoir V, Philippon A, Allesoe RL, Rebelo AR, Florensa AF, Fagelhauer L, Chakraborty T, Neumann B, Werner G, Bender JK, Stingl K, Nguyen M, Coppens J, Xavier BB, Malhotra-Kumar S, Westh H, Pinholt M, Anjum MF, Duggett NA, Kempf I, Nykäsenoja S, Olkkola S, Wieczorek K, Amaro A, Clemente L, Mossong J, Losch S, Ragimbeau C, Lund O, Aarestrup FM. ResFinder 4.0 for predictions of phenotypes from genotypes. J Antimicrob Chemother 2021; 75:3491-3500. [PMID: 32780112 PMCID: PMC7662176 DOI: 10.1093/jac/dkaa345] [Citation(s) in RCA: 1309] [Impact Index Per Article: 436.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/30/2020] [Indexed: 12/16/2022] Open
Abstract
Objectives WGS-based antimicrobial susceptibility testing (AST) is as reliable as phenotypic AST for several antimicrobial/bacterial species combinations. However, routine use of WGS-based AST is hindered by the need for bioinformatics skills and knowledge of antimicrobial resistance (AMR) determinants to operate the vast majority of tools developed to date. By leveraging on ResFinder and PointFinder, two freely accessible tools that can also assist users without bioinformatics skills, we aimed at increasing their speed and providing an easily interpretable antibiogram as output. Methods The ResFinder code was re-written to process raw reads and use Kmer-based alignment. The existing ResFinder and PointFinder databases were revised and expanded. Additional databases were developed including a genotype-to-phenotype key associating each AMR determinant with a phenotype at the antimicrobial compound level, and species-specific panels for in silico antibiograms. ResFinder 4.0 was validated using Escherichia coli (n = 584), Salmonella spp. (n = 1081), Campylobacter jejuni (n = 239), Enterococcus faecium (n = 106), Enterococcus faecalis (n = 50) and Staphylococcus aureus (n = 163) exhibiting different AST profiles, and from different human and animal sources and geographical origins. Results Genotype–phenotype concordance was ≥95% for 46/51 and 25/32 of the antimicrobial/species combinations evaluated for Gram-negative and Gram-positive bacteria, respectively. When genotype–phenotype concordance was <95%, discrepancies were mainly linked to criteria for interpretation of phenotypic tests and suboptimal sequence quality, and not to ResFinder 4.0 performance. Conclusions WGS-based AST using ResFinder 4.0 provides in silico antibiograms as reliable as those obtained by phenotypic AST at least for the bacterial species/antimicrobial agents of major public health relevance considered.
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Affiliation(s)
- Valeria Bortolaia
- Technical University of Denmark, National Food Institute, European Union Reference Laboratory for Antimicrobial Resistance, WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens and Genomics, FAO Reference Laboratory for Antimicrobial Resistance, Kgs. Lyngby, Denmark
| | - Rolf S Kaas
- Technical University of Denmark, National Food Institute, European Union Reference Laboratory for Antimicrobial Resistance, WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens and Genomics, FAO Reference Laboratory for Antimicrobial Resistance, Kgs. Lyngby, Denmark
| | | | - Marilyn C Roberts
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Stefan Schwarz
- Institute of Microbiology and Epizootics, Centre for Infection Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Vincent Cattoir
- Rennes University Hospital, Department of Clinical Microbiology, Rennes, France.,National Reference Center for Antimicrobial Resistance (lab Enterococci), Rennes, France.,University of Rennes 1, INSERM U1230, Rennes, France
| | - Alain Philippon
- Faculty of Medicine Paris Descartes, Bacteriology, Paris, France
| | - Rosa L Allesoe
- Technical University of Denmark, National Food Institute, European Union Reference Laboratory for Antimicrobial Resistance, WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens and Genomics, FAO Reference Laboratory for Antimicrobial Resistance, Kgs. Lyngby, Denmark.,Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen N, Denmark
| | - Ana Rita Rebelo
- Technical University of Denmark, National Food Institute, European Union Reference Laboratory for Antimicrobial Resistance, WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens and Genomics, FAO Reference Laboratory for Antimicrobial Resistance, Kgs. Lyngby, Denmark
| | - Alfred Ferrer Florensa
- Technical University of Denmark, National Food Institute, European Union Reference Laboratory for Antimicrobial Resistance, WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens and Genomics, FAO Reference Laboratory for Antimicrobial Resistance, Kgs. Lyngby, Denmark
| | - Linda Fagelhauer
- Institute of Medical Microbiolgy, Justus Liebig University Giessen, Giessen, Germany.,German Center for Infection Research, site Giessen-Marburg-Langen, Justus Liebig University Giessen, Giessen, Germany.,Institute of Hygiene and Environmental Medicine, Justus Liebig University Giessen, Giessen, Germany
| | - Trinad Chakraborty
- Institute of Medical Microbiolgy, Justus Liebig University Giessen, Giessen, Germany.,German Center for Infection Research, site Giessen-Marburg-Langen, Justus Liebig University Giessen, Giessen, Germany
| | - Bernd Neumann
- Robert Koch Institute, Wernigerode Branch, Department of Infectious Diseases, Division of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode, Germany
| | - Guido Werner
- Robert Koch Institute, Wernigerode Branch, Department of Infectious Diseases, Division of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode, Germany
| | - Jennifer K Bender
- Robert Koch Institute, Wernigerode Branch, Department of Infectious Diseases, Division of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode, Germany
| | - Kerstin Stingl
- German Federal Institute for Risk Assessment, Department of Biological Safety, National Reference Laboratory for Campylobacter, Berlin, Germany
| | - Minh Nguyen
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, Belgium
| | - Jasmine Coppens
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, Belgium
| | - Basil Britto Xavier
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, Belgium
| | - Surbhi Malhotra-Kumar
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, Belgium
| | - Henrik Westh
- Department of Clinical Microbiology, Hvidovre University Hospital, Hvidovre, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Mette Pinholt
- Department of Clinical Microbiology, Hvidovre University Hospital, Hvidovre, Denmark
| | - Muna F Anjum
- Animal and Plant Health Agency, Addlestone, Surrey, UK
| | | | - Isabelle Kempf
- ANSES, Ploufragan-Plouzané-Niort Laboratory, Ploufragan, France
| | | | | | | | - Ana Amaro
- National Institute of Agrarian and Veterinary Research (INIAV), National Reference Laboratory for Animal Health, Oeiras, Portugal
| | - Lurdes Clemente
- National Institute of Agrarian and Veterinary Research (INIAV), National Reference Laboratory for Animal Health, Oeiras, Portugal
| | - Joël Mossong
- Laboratoire National de Santé, Epidemiology and Microbial Genomics, Dudelange, Luxembourg
| | - Serge Losch
- Laboratoire de Médecine Vétérinaire de l'Etat, Veterinary Services Administration, Dudelange, Luxembourg
| | - Catherine Ragimbeau
- Laboratoire National de Santé, Epidemiology and Microbial Genomics, Dudelange, Luxembourg
| | - Ole Lund
- Technical University of Denmark, National Food Institute, European Union Reference Laboratory for Antimicrobial Resistance, WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens and Genomics, FAO Reference Laboratory for Antimicrobial Resistance, Kgs. Lyngby, Denmark
| | - Frank M Aarestrup
- Technical University of Denmark, National Food Institute, European Union Reference Laboratory for Antimicrobial Resistance, WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens and Genomics, FAO Reference Laboratory for Antimicrobial Resistance, Kgs. Lyngby, Denmark
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Velasova M, Smith RP, Lemma F, Horton RA, Duggett NA, Evans J, Tongue SC, Anjum MF, Randall LP. Detection of extended-spectrum β-lactam, AmpC and carbapenem resistance in Enterobacteriaceae in beef cattle in Great Britain in 2015. J Appl Microbiol 2019; 126:1081-1095. [PMID: 30693606 DOI: 10.1111/jam.14211] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/02/2019] [Accepted: 01/21/2019] [Indexed: 02/06/2023]
Abstract
AIMS This study investigated the occurrence and genetic diversity of Enterobacteriaceae with extended-spectrum β-lactamase (ESBL)-, AmpC- and carbapenemase-mediated resistance in British beef cattle, and related risk factors. METHODS AND RESULTS Faecal samples (n = 776) were obtained from farms in England and Wales (n = 20) and Scotland (n = 20) in 2015. Isolates from selective agars were identified by MALDI ToF mass spectrometry. Selected isolates were characterized by multiplex PCR (blaCTX -M, blaOXA , blaSHV and blaTEM genes), whole-genome sequencing (WGS), minimum inhibitory concentrations and pulsed-field gel electrophoresis. None of the faecal samples yielded carbapenem-resistant Escherichia coli. Ten (25%) of the farms tested positive for ESBL-producing CTX-M Enterobacteriaceae, 15 (37·5%) of the farms were positive for AmpC phenotype E. coli and none were positive for carbapenem-resistant E. coli. WGS showed a total of 30 different resistance genes associated with E. coli, Citrobacter and Serratia from ESBL agars, and colocation of resistance genes with blaCTX -M1 . Buying bulls and bringing in fattening cattle from another farm were identified as significant risk factors for positive samples harbouring CTX-M Enterobacteriaceae or AmpC phenotype E. coli respectively. CONCLUSIONS Beef cattle on a proportion of farms in GB carry ESBL-producing Enterobacteriaceae. Factors, such as operating as a closed herd, may have an important role in reducing introduction and transmission of resistant Enterobacteriaceae. The results indicate management factors may play an important role in impacting ESBL prevalence. In particular, further study would be valuable to understand the impact of maintaining a closed herd on reducing the introduction of resistant Enterobacteriaceae. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first study showing the presence of ESBL-producing Enterobacteriaceae in British beef cattle.
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Affiliation(s)
- M Velasova
- Animal and Plant Health Agency (Weybridge), Addlestone, UK
| | - R P Smith
- Animal and Plant Health Agency (Weybridge), Addlestone, UK
| | - F Lemma
- Animal and Plant Health Agency (Weybridge), Addlestone, UK
| | - R A Horton
- Animal and Plant Health Agency (Weybridge), Addlestone, UK
| | - N A Duggett
- Animal and Plant Health Agency (Weybridge), Addlestone, UK
| | - J Evans
- SRUC (Inverness Campus), Edinburgh, UK
| | | | - M F Anjum
- Animal and Plant Health Agency (Weybridge), Addlestone, UK
| | - L P Randall
- Animal and Plant Health Agency (Weybridge), Addlestone, UK
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Duggett NA, Randall LP, Horton RA, Lemma F, Kirchner M, Nunez-Garcia J, Brena C, Williamson SM, Teale C, Anjum MF. Molecular epidemiology of isolates with multiple mcr plasmids from a pig farm in Great Britain: the effects of colistin withdrawal in the short and long term. J Antimicrob Chemother 2018; 73:3025-3033. [DOI: 10.1093/jac/dky292] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 06/25/2018] [Indexed: 12/22/2022] Open
Affiliation(s)
- Nicholas A Duggett
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey, UK
| | - Luke P Randall
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey, UK
| | - Robert A Horton
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey, UK
| | - Fabrizio Lemma
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey, UK
| | - Miranda Kirchner
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey, UK
| | | | - Camilla Brena
- Animal and Plant Health Agency (Thirsk), West House, Station Road, Thirsk, North Yorkshire, UK
| | - Susanna M Williamson
- Animal and Plant Health Agency (Bury St Edmunds), Rougham Hill, Bury St Edmunds, Suffolk, UK
| | - Christopher Teale
- Animal and Plant Health Agency (Shrewsbury), Kendal Road, Shrewsbury, UK
| | - Muna F Anjum
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey, UK
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5
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Duggett NA, Sayers E, AbuOun M, Ellis RJ, Nunez-Garcia J, Randall L, Horton R, Rogers J, Martelli F, Smith RP, Brena C, Williamson S, Kirchner M, Davies R, Crook D, Evans S, Teale C, Anjum MF. Occurrence and characterization of mcr-1-harbouring Escherichia coli isolated from pigs in Great Britain from 2013 to 2015. J Antimicrob Chemother 2017; 72:691-695. [PMID: 27999032 DOI: 10.1093/jac/dkw477] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 10/07/2016] [Indexed: 11/14/2022] Open
Abstract
Objectives 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. Methods 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. Results 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%. Conclusions 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.
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Affiliation(s)
- Nicholas A Duggett
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | - Ellie Sayers
- 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
| | - Manal AbuOun
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | - Richard J Ellis
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | | | - Luke Randall
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | - Robert Horton
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | - Jon Rogers
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | - Francesca Martelli
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | - Richard P Smith
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | - Camilla Brena
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | - Susanna Williamson
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | - Miranda Kirchner
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | - Robert Davies
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | - Derrick Crook
- Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford University, Oxford OX3 7BN, UK
| | - Sarah Evans
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | - Chris Teale
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
| | - Muna F Anjum
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone KT15 3NB, UK
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6
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Anjum MF, Duggett NA, AbuOun M, Randall L, Nunez-Garcia J, Ellis RJ, Rogers J, Horton R, Brena C, Williamson S, Martelli F, Davies R, Teale C. Colistin resistance in Salmonella and Escherichia coli isolates from a pig farm in Great Britain. J Antimicrob Chemother 2016; 71:2306-13. [PMID: 27147305 DOI: 10.1093/jac/dkw149] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 03/31/2016] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES The objective of this study was to characterize colistin-resistant bacteria isolated from pigs on a farm in Great Britain following identification of a plasmid-borne colistin resistance mechanism in Escherichia coli from China. METHODS Phenotypic antimicrobial susceptibility testing was undertaken by broth dilution and WGS was performed to detect the presence of genes encoding resistance and virulence. Transferable colistin resistance was investigated by conjugation. RESULTS Two E. coli and one Salmonella Typhimurium variant Copenhagen were shown to be MDR, including resistance to colistin, with one E. coli and the Salmonella carrying the mcr-1 gene; all three harboured chromosomal mutations in genes conferring colistin resistance and both E. coli harboured β-lactamase resistance. The Salmonella mcr-1 plasmid was highly similar to pHNSHP45, from China, while the E. coli mcr-1 plasmid only had the ISApII and mcr-1 genes in common. The frequency of mcr-1 plasmid transfer by conjugation to recipient Enterobacteriaceae from Salmonella was low, lying between 10(-7) and 10(-9) cfu/recipient cfu. We were unable to demonstrate mcr-1 plasmid transfer from the E. coli. Plasmid profiling indicated transfer of multiple plasmids from the Salmonella resulting in some MDR transconjugants. CONCLUSIONS Identification of the mcr-1 gene in Enterobacteriaceae from pigs confirms its presence in livestock in Great Britain. The results suggest dissemination of resistance through different horizontally transferable elements. The in vitro transfer of multiple plasmids carrying colistin and other resistances from the Salmonella isolate underlines the potential for wider dissemination and recombination.
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Affiliation(s)
- Muna F Anjum
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Nicholas A Duggett
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Manal AbuOun
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Luke Randall
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Javier Nunez-Garcia
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Richard J Ellis
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Jon Rogers
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Robert Horton
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Camilla Brena
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Susanna Williamson
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Francesca Martelli
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Robert Davies
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Christopher Teale
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
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