{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T13:20:02Z","timestamp":1780320002745,"version":"3.54.1"},"reference-count":37,"publisher":"Oxford University Press (OUP)","issue":"3","license":[{"start":{"date-parts":[[2020,1,17]],"date-time":"2020-01-17T00:00:00Z","timestamp":1579219200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"funder":[{"DOI":"10.13039\/100005825","name":"USDA National Institute of Food and Agriculture","doi-asserted-by":"crossref","award":["1014385"],"award-info":[{"award-number":["1014385"]}],"id":[{"id":"10.13039\/100005825","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2020,3,1]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Studies suggest a link between added copper (Cu) and co-selection of antimicrobial resistance (AMR) in Enterococcus spp., but data are inconsistent. This study aimed to assess the impact of added Cu, alone or with a feed-grade antimicrobial, on growth performance, transferable Cu resistance gene (tcrB) prevalence, abundance of tcrB in fecal community DNA, and AMR in fecal enterococci in weaned piglets. A total of 320 barrows (DNA 200\u2005\u00d7\u2005400, DNA Genetics) weaned at approximately 21 d of age with 7.4 kg (7.4\u2005\u00b1\u20050.06 kg) BW were used in a 28-d study. Piglets were fed a common non-medicated diet for 7 d of acclimation. Treatments were arranged in a 2\u2005\u00d7\u20052 factorial design with main effects of added Cu (0 vs. 200 mg\/kg Cu from Cu sulfate) and chlortetracycline (0 vs. 440 mg\/kg CTC). Growth performance and fecal samples were obtained on days 0, 14, and 28. There was no evidence (P\u2005&amp;gt;\u20050.05) for Cu and CTC interaction in growth performance. Pigs fed diets with added Cu had increased (P\u2005&amp;lt;\u20050.05) ADG and ADFI from days 0 to 14, with no evidence for differences (P\u2005&amp;gt;\u20050.05) from days 15 to 28 and 0 to 28. Pigs fed diets with CTC had improved (P\u2005&amp;lt;\u20050.01) ADG, ADFI, and G:F from days 0 to 28. Prevalence of tcrB-positive enterococci was not affected by the addition of Cu and\/or CTC (P\u2005&amp;gt;\u20050.05). Prevalence of tcrB-positive enterococci was higher on day 14 than other sampling days (P\u2005=\u20050.002). Prevalence of tetracycline resistance gene [tet(M)]-positive enterococci was not affected by treatments or day (P\u2005&amp;gt;\u20050.05). Prevalence of macrolide resistance gene [erm(B)]-positive enterococci had a significant treatment and sampling day interaction (P\u2005=\u20050.021). The abundance of the tcrB gene in feces, quantified by PCR, was not affected by Cu treatment. The median Cu minimum inhibitory concentrations (MIC) of tcrB-negative and -positive isolates were 3 and 20 mM, respectively (P\u2005&amp;lt;\u20050.001). For day 0 and day 28, all Enterococcus isolates were susceptible to gentamicin, kanamycin, streptomycin, daptomycin, and tigecycline, with a majority of isolates resistant to chloramphenicol, erythromycin, lincomycin, linezolid, tetracycline, tylosin tartrate, and Synercid. In conclusion, 200 mg\/kg added Cu or 440 mg\/kg CTC in nursery diets improved growth performance of nursery pigs. Added Cu, with or without a selection pressure of CTC, did not increase Cu-resistant enterococci and did not co-select resistance to antibiotics.<\/jats:p>","DOI":"10.1093\/jas\/skaa003","type":"journal-article","created":{"date-parts":[[2020,1,17]],"date-time":"2020-01-17T05:46:33Z","timestamp":1579239993000},"source":"Crossref","is-referenced-by-count":12,"title":["Impact of added copper, alone or in combination with chlortetracycline, on growth performance and antimicrobial resistance of fecal enterococci of weaned piglets"],"prefix":"10.1093","volume":"98","author":[{"given":"Kaylen M","family":"Capps","sequence":"first","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9689-1124","authenticated-orcid":false,"given":"Raghavendra G","family":"Amachawadi","sequence":"first","affiliation":[{"name":"Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mariana B","family":"Menegat","sequence":"first","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jason C","family":"Woodworth","sequence":"first","affiliation":[{"name":"Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan, KS"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kurt","family":"Perryman","sequence":"first","affiliation":[{"name":"Micronutrients, Indianapolis, IN"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mike D","family":"Tokach","sequence":"first","affiliation":[{"name":"Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan, KS"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6371-0729","authenticated-orcid":false,"given":"Steve S","family":"Dritz","sequence":"first","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joel M","family":"DeRouchey","sequence":"first","affiliation":[{"name":"Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan, KS"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robert D","family":"Goodband","sequence":"first","affiliation":[{"name":"Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan, KS"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jianfa","family":"Bai","sequence":"first","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mike D","family":"Apley","sequence":"first","affiliation":[{"name":"Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Brian V","family":"Lubbers","sequence":"first","affiliation":[{"name":"Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0899-878X","authenticated-orcid":false,"given":"Tiruvoor G","family":"Nagaraja","sequence":"first","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2020,1,17]]},"reference":[{"key":"2020071315022876900_CIT0001","doi-asserted-by":"crossref","first-page":"670","DOI":"10.1089\/fpd.2015.1961","article-title":"Effects of in-feed copper, chlortetracycline, and tylosin on the prevalence of transferable copper resistance gene, tcrB, among fecal enterococci of weaned piglets","volume":"12","author":"Amachawadi","year":"2015","journal-title":"Foodborne Pathog. 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