Prevalence and Risk Factors Associated With Antimicrobial Resistance in Bacteria Related to Bovine Respiratory Disease-A Broad Cross-Sectional Study of Beef Cattle at Entry Into Canadian Feedlots.

Sara Andrés-Lasheras,Sherry J Hannon,Joyce Van Donkersgoed,Rahat Zaheer,Reuben Ha,Catrione Lee,Tim A Mcallister,Calvin W Booker,Michele Anholt,Steve Hendrick,Rob Deardon,Craig Dorin,Sheryl Gow

doi:10.3389/fvets.2021.692646

Abstract

A broad, cross-sectional study of beef cattle at entry into Canadian feedlots investigated the prevalence and epidemiology of antimicrobial resistance (AMR) in Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis, bacterial members of the bovine respiratory disease (BRD) complex. Upon feedlot arrival and before antimicrobials were administered at the feedlot, deep nasopharyngeal swabs were collected from 2,824 feedlot cattle in southern and central Alberta, Canada. Data on the date of feedlot arrival, cattle type (beef, dairy), sex (heifer, bull, steer), weight (kg), age class (calf, yearling), source (ranch direct, auction barn, backgrounding operations), risk of developing BRD (high, low), and weather conditions at arrival (temperature, precipitation, and estimated wind speed) were obtained. Mannheimia haemolytica, P. multocida, and H. somni isolates with multidrug-resistant (MDR) profiles associated with the presence of integrative and conjugative elements were isolated more often from dairy-type than from beef-type cattle. Our results showed that beef-type cattle from backgrounding operations presented higher odds of AMR bacteria as compared to auction-derived calves. Oxytetracycline resistance was the most frequently observed resistance across all Pasteurellaceae species and cattle types. Mycoplasma bovis exhibited high macrolide minimum inhibitory concentrations in both cattle types. Whether these MDR isolates establish and persist within the feedlot environment, requires further evaluation.

Highlights

Bovine respiratory disease (BRD) continues to be a challenging and costly disease in feedlot cattle in North America [1,2,3], accounting for 70–80% and 40–50% of the total herd-level morbidity and mortality, respectively [4]
We described the prevalence of antimicrobial resistance (AMR) in M. haemolytica, P. multocida, and H. somni in cattle at feedlot arrival, and documented that it was higher in dairy than beef-type cattle
Many of the MDR Pasteurellaceae harbor antimicrobial-resistance genes (ARG) on integrative and conjugative element (ICE) and it is unknown if bacteria carrying these elements increase and spread among cattle within the feedlot, a possibility that deserves further evaluation. This is the first published study in Alberta documenting AMR in four major bacterial species involved in the BRD complex isolated from beef and dairy-type cattle on feedlot arrival

Summary

Introduction

Bovine respiratory disease (BRD) continues to be a challenging and costly disease in feedlot cattle in North America [1,2,3], accounting for 70–80% and 40–50% of the total herd-level morbidity and mortality, respectively [4]. Considerable resources have been invested in the development of technologies and management strategies to mitigate and treat BRD, but the incidence of morbidity and mortality have remained relatively constant over the last 45 years [8]. Practices such as preconditioning, improved diagnostics, and new vaccines continue to be developed, investigated, and validated as alternatives to antimicrobials. Until these alternatives are shown to be cost-effective, practically implementable, and on-par or surpass currently available practices, it is likely that antimicrobial therapy will continue to be an important tool for preventing, treating, and controlling BRD in feedlot cattle

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