title: Modelling considerations in the analysis of associations between antimicrobial use and resistance in beef feedlot cattle.
abstract: A number of sophisticated modelling approaches are available to investigate potential associations between antimicrobial use (AMU) and resistance (AMR) in animal health settings. All have their advantages and disadvantages, making it unclear as to which model is most appropriate. We used advanced regression modelling to investigate AMU-AMR associations in faecal non-type-specific Escherichia coli (NTSEC) isolates recovered from 275 pens of feedlot cattle. Ten modelling strategies were employed to investigate AMU associations with resistance to chloramphenicol, ampicillin, sulfisoxazole, tetracycline and streptomycin. Goodness-of-fit statistics did not show a consistent advantage for any one model type. Three AMU-AMR associations were significant in all models. Recent parenteral tetracycline use increased the odds of finding tetracycline-resistant NTSEC [odds ratios (OR) 1·1-3·2]; recent parenteral sulfonamide use increased the odds of finding sulfisoxazole-resistant NTSEC (OR 1·4-2·5); and recent parenteral macrolide use decreased the odds of recovering ampicillin-resistant NTSEC (OR 0·03-0·2). Other results varied markedly depending on the modelling approach, emphasizing the importance of exploring and reporting multiple modelling methods based on a balanced consideration of important factors such as study design, mathematical appropriateness, research question and target audience.
authors.affiliation: Department of Clinical Sciences,College of Veterinary Medicine and Biomedical Sciences,Colorado State University,Fort Collins,CO,USA.
authors.forename: N R
authors.initials: NR
authors.lastname: Noyes
authors.affiliation: Department of Clinical Sciences,College of Veterinary Medicine and Biomedical Sciences,Colorado State University,Fort Collins,CO,USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Benedict
authors.affiliation: Centre for Food-borne,Environmental Zoonotic Infectious Diseases,Public Health Agency of Canada,University of Saskatoon,Saskatchewan,Canada.
authors.forename: S P
authors.initials: SP
authors.lastname: Gow
authors.affiliation: Western College of Veterinary Medicine,University of Saskatchewan,Saskatoon,Canada.
authors.forename: C L
authors.initials: CL
authors.lastname: Waldner
authors.affiliation: Centre for Food-borne,Environmental Zoonotic Infectious Diseases,Public Health Agency of Canada,Guelph,Ontario,Canada.
authors.forename: R J
authors.initials: RJ
authors.lastname: Reid-Smith
authors.affiliation: Feedlot Health Management Services, Ltd.,Okotoks,Alberta,Canada.
authors.forename: C W
authors.initials: CW
authors.lastname: Booker
authors.affiliation: Lethbridge Research Center,University of Lethbridge,Lethbridge,Alberta,Canada.
authors.forename: T A
authors.initials: TA
authors.lastname: McAllister
authors.affiliation: Department of Clinical Sciences,College of Veterinary Medicine and Biomedical Sciences,Colorado State University,Fort Collins,CO,USA.
authors.forename: P S
authors.initials: PS
authors.lastname: Morley
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002170:Canada / Q000453:epidemiology; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects*; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D008954:Models, Biological
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antimicrobial drugs; Escherichia coli; antimicrobial resistance in agricultural settings; mathematical modelling; surveillance