title: Risk factors for occurrence of cephalosporin-resistant Escherichia coli in Norwegian broiler flocks.
abstract: A longitudinal study of 27 broiler farms including 182 broiler flocks was performed to determine risk factors for occurrence of cephalosporin-resistant Escherichia coli in Norwegian broiler flocks. Information regarding possible risk factors was collected by an online questionnaire and by samples obtained from broiler and parent flocks during the study period. Additional information was provided by the broiler production company. The prevalence of cephalosporin-resistant E. coli in parent flocks and broiler flocks sampled in the study was estimated. Cephalosporin-resistant E. coli was detected in 13.8% of the parent flocks and 22.5% of the broiler flocks included in the study. A multivariable generalized linear model was used to estimate risk factors. The risk for occurrence of cephalosporin-resistant E. coli was associated with the status of the previous flock in the broiler house (odds ratio=12.7), number of parent flocks supplying the broiler flock with day-old chickens (odds ratio=6.3), routines for disinfection of floor between production cycles (odds ratio=0.1), and transport personnel entering the room where the broilers are raised (odds ratio=9.3). Our findings highlights that implementation of a high level of biosecurity with a minimal number of people entering the broiler house during production cycles, as well as rigorous cleaning and disinfection routines between production cycles will contribute to a decrease in the occurrence of cephalosporin-resistant E. coli in broiler flocks provided that there is no selection pressure from antimicrobial use in the broiler production.
authors.affiliation: Norwegian Veterinary Institute, Pb 750 Sentrum, 0106 Oslo, Norway. Electronic address: solveig.mo@vetinst.no.
authors.forename: Solveig Sølverød
authors.initials: SS
authors.lastname: Mo
authors.affiliation: Norwegian Veterinary Institute, Pb 750 Sentrum, 0106 Oslo, Norway. Electronic address: anja.kristoffersen@vetinst.no.
authors.forename: Anja Bråthen
authors.initials: AB
authors.lastname: Kristoffersen
authors.affiliation: Norwegian Veterinary Institute, Pb 750 Sentrum, 0106 Oslo, Norway; Norwegian Institute of Public Health, Pb 4404 Nydalen, 0403 Oslo, Norway. Electronic address: marianne.sunde@vetinst.no.
authors.forename: Marianne
authors.initials: M
authors.lastname: Sunde
authors.affiliation: Norwegian University of Life Sciences, Pb 8146 Dep., 0033 Oslo, Norway. Electronic address: ane.nodtvedt@nmbu.no.
authors.forename: Ane
authors.initials: A
authors.lastname: Nødtvedt
authors.affiliation: Norwegian Veterinary Institute, Pb 750 Sentrum, 0106 Oslo, Norway. Electronic address: madelaine.norstrom@vetinst.no.
authors.forename: Madelaine
authors.initials: M
authors.lastname: Norström
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology; D002645:Chickens; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000453:epidemiology / Q000662:veterinary*; D016014:Linear Models; D008137:Longitudinal Studies; D009664:Norway / Q000453:epidemiology; D011201:Poultry Diseases / Q000188:drug therapy / Q000453:epidemiology*; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins
keywords: AmpC; Antimicrobial resistance; Biosecurity; Broiler; E. coli; Risk factor