@article{063a1cd5ebc44f2791324a3d4075b3b7,
title = "Metaphylactic antimicrobial effects on occurrences of antimicrobial resistance in Salmonella enterica, Escherichia coli and Enterococcus spp. measured longitudinally from feedlot arrival to harvest in high-risk beef cattle",
abstract = "Aims: Our objective was to determine how injectable antimicrobials affected populations of Salmonella enterica, Escherichia coli and Enterococcus spp. in feedlot cattle. Methods and Results: Two arrival date blocks of high-risk crossbred beef cattle (n = 249; mean BW = 244 kg) were randomly assigned one of four antimicrobial treatments administered on day 0: sterile saline control (CON), tulathromycin (TUL), ceftiofur (CEF) or florfenicol (FLR). Faecal samples were collected on days 0, 28, 56, 112, 182 and study end (day 252 for block 1 and day 242 for block 2). Hide swabs and subiliac lymph nodes were collected the day before and the day of harvest. Samples were cultured for antimicrobial-resistant Salmonella, Escherichia coli and Enterococcus spp. The effect of treatment varied by day across all targeted bacterial populations (p ≤ 0.01) except total E. coli. Total E. coli counts were greatest on days 112, 182 and study end (p ≤ 0.01). Tulathromycin resulted in greater counts and prevalence of Salmonella from faeces than CON at study end (p ≤ 0.01). Tulathromycin and CEF yielded greater Salmonella hide prevalence and greater counts of 128ERYR E. coli at study end than CON (p ≤ 0.01). No faecal Salmonella resistant to tetracyclines or third-generation cephalosporins were detected. Ceftiofur was associated with greater counts of 8ERYR Enterococcus spp. at study end (p ≤ 0.03). By the day before harvest, antimicrobial use did not increase prevalence or counts for all other bacterial populations compared with CON (p ≥ 0.13). Conclusions: Antimicrobial resistance (AMR) in feedlot cattle is not caused solely by using a metaphylactic antimicrobial on arrival, but more likely a multitude of environmental and management factors.",
keywords = "Enterococcus, Escherichia coli, Metaphylaxis, Salmonella, antimicrobial resistance, feedlot cattle, injectable antimicrobials",
author = "Long, {Nathan S.} and Wells, {James E.} and Berry, {Elaine D.} and Legako, {Jerrad F.} and Woerner, {Dale R.} and Loneragan, {Guy H.} and Broadway, {Paul R.} and Carroll, {Jeff A.} and Sanchez, {Nicole C.Burdick} and Fernando, {Samodha C.} and Bacon, {Carley M.} and Helmuth, {Cory L.} and Smock, {Taylor M.} and Manahan, {Jeff L.} and Hoffman, {Ashley A.} and Hales, {Kristin E.}",
note = "Funding Information: This work was supported by Mitigating Antimicrobial Resistance, grant number 2020-68015-30857, project accession no. 1022218 from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions or recommendations expressed in this presentation are those of the authors and do not necessarily reflect the view of the U.S. Department of Agriculture. Additional funding was provided by the Beef Checkoff. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA. USDA is an equal opportunity provider and employer. Funding Information: This work was supported by Mitigating Antimicrobial Resistance, grant number 2020‐68015‐30857, project accession no. 1022218 from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions or recommendations expressed in this presentation are those of the authors and do not necessarily reflect the view of the U.S. Department of Agriculture. Additional funding was provided by the Beef Checkoff. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA. USDA is an equal opportunity provider and employer. Publisher Copyright: {\textcopyright} 2022 The Authors. Journal of Applied Microbiology published by John Wiley & Sons Ltd on behalf of Society for Applied Microbiology.",
year = "2022",
month = sep,
doi = "10.1111/jam.15691",
language = "English (US)",
volume = "133",
pages = "1940--1955",
journal = "Proceedings of the Society for Applied Bacteriology",
issn = "1364-5072",
publisher = "Wiley-Blackwell",
number = "3",
}