title: Copper resistance in Enterococcus faecium, mediated by the tcrB gene, is selected by supplementation of pig feed with copper sulfate.
abstract: The tcr gene cluster mediates in vitro copper resistance in Enterococcus faecium. Here we describe the selection of tcr-mediated copper resistance in E. faecium in an animal feeding experiment with young pigs fed 175 mg copper/kg feed (ppm), which is the concentration commonly used for piglets in European pig production. tcr-mediated copper resistance was not selected for in a control group fed low levels of copper (6 ppm). We also show coselection of macrolide- and glycopeptide-resistant E. faecium in the animal group fed the high level of copper. Finally, we identify the tcr genes in the enterococcal species E. mundtii, E. casseliflavus, and E. gallinarum for the first time.
authors.affiliation: Danish Institute for Food and Veterinary Research, Bülowsvej 27, 1790 Copenhagen V, Denmark. hha@dfvf.dk
authors.forename: Henrik
authors.initials: H
authors.lastname: Hasman
authors.forename: Isabelle
authors.initials: I
authors.lastname: Kempf
authors.forename: Bérangère
authors.initials: B
authors.lastname: Chidaine
authors.forename: Roland
authors.initials: R
authors.lastname: Cariolet
authors.forename: Annette Kjaer
authors.initials: AK
authors.lastname: Ersbøll
authors.forename: Hans
authors.initials: H
authors.lastname: Houe
authors.forename: Hans Christian
authors.initials: HC
authors.lastname: Bruun Hansen
authors.forename: Frank Møller
authors.initials: FM
authors.lastname: Aarestrup
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D003300:Copper / Q000494:pharmacology*; D019327:Copper Sulfate / Q000008:administration & dosage / Q000032:analysis; D024881:Drug Resistance, Bacterial / Q000235:genetics; D016984:Enterococcus faecium / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D005798:Genes, Bacterial; D006133:Growth Substances / Q000008:administration & dosage; D012641:Selection, Genetic; D034421:Sus scrofa / Q000382:microbiology*
chemical_list: D001426:Bacterial Proteins; D006133:Growth Substances; C461665:TcrB protein, Enterococcus faecium; D003300:Copper; D019327:Copper Sulfate