title: Carbapenemase-Producing Enterobacteriaceae Recovered from the Environment of a Swine Farrow-to-Finish Operation in the United States.
abstract: Carbapenem-resistant Enterobacteriaceae (CRE) present an urgent threat to public health. While use of carbapenem antimicrobials is restricted for food-producing animals, other β-lactams, such as ceftiofur, are used in livestock. This use may provide selection pressure favoring the amplification of carbapenem resistance, but this relationship has not been established. Previously unreported among U.S. livestock, plasmid-mediated CRE have been reported from livestock in Europe and Asia. In this study, environmental and fecal samples were collected from a 1,500-sow, U.S. farrow-to-finish operation during 4 visits over a 5-month period in 2015. Samples were screened using selective media for the presence of CRE, and the resulting carbapenemase-producing isolates were further characterized. Of 30 environmental samples collected from a nursery room on our initial visit, 2 (7%) samples yielded 3 isolates, 2 sequence type 218 (ST 218) Escherichia coli and 1 Proteus mirabilis, carrying the metallo-β-lactamase gene blaIMP-27on IncQ1 plasmids. We recovered on our third visit 15 IMP-27-bearing isolates of multiple Enterobacteriaceae species from 11 of 24 (46%) environmental samples from 2 farrowing rooms. These isolates each also carried blaIMP-27on IncQ1 plasmids. No CRE isolates were recovered from fecal swabs or samples in this study. As is common in U.S. swine production, piglets on this farm receive ceftiofur at birth, with males receiving a second dose at castration (≈day 6). This selection pressure may favor the dissemination of blaIMP-27-bearing Enterobacteriaceae in this farrowing barn. The absence of this selection pressure in the nursery and finisher barns likely resulted in the loss of the ecological niche needed for maintenance of this carbapenem resistance gene.
authors.affiliation: Department of Veterinary Preventive Medicine, The Ohio State University College of Veterinary Medicine, Columbus, Ohio, USA.
authors.forename: Dixie F
authors.initials: DF
authors.lastname: Mollenkopf
authors.affiliation: Department of Veterinary Preventive Medicine, The Ohio State University College of Veterinary Medicine, Columbus, Ohio, USA.
authors.forename: Jason W
authors.initials: JW
authors.lastname: Stull
authors.affiliation: Department of Veterinary Preventive Medicine, The Ohio State University College of Veterinary Medicine, Columbus, Ohio, USA.
authors.forename: Dimitria A
authors.initials: DA
authors.lastname: Mathys
authors.affiliation: Department of Veterinary Preventive Medicine, The Ohio State University College of Veterinary Medicine, Columbus, Ohio, USA.
authors.forename: Andrew S
authors.identifier: 0000-0002-0738-8453
authors.initials: AS
authors.lastname: Bowman
authors.affiliation: Department of Veterinary Preventive Medicine, The Ohio State University College of Veterinary Medicine, Columbus, Ohio, USA.
authors.forename: Sydnee M
authors.initials: SM
authors.lastname: Feicht
authors.affiliation: Department of Veterinary Preventive Medicine, The Ohio State University College of Veterinary Medicine, Columbus, Ohio, USA.
authors.forename: Susan V
authors.initials: SV
authors.lastname: Grooters
authors.affiliation: Department of Veterinary Clinical Sciences, The Ohio State University College of Veterinary Medicine, Columbus, Ohio, USA.
authors.forename: Joshua B
authors.initials: JB
authors.lastname: Daniels
authors.affiliation: Department of Veterinary Preventive Medicine, The Ohio State University College of Veterinary Medicine, Columbus, Ohio, USA wittum.1@osu.edu.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Wittum
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D002511:Cephalosporins / Q000494:pharmacology; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D000072480:Farms; D005243:Feces / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D009515:New Jersey; D013552:Swine; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D002511:Cephalosporins; C053503:ceftiofur; D001618:beta-Lactamases; C063912:carbapenemase
keywords: IMP-27; carbapenemase-producing Enterobacteriaceae; livestock; plasmid-mediated resistance