title: Risk factors for quinolone-resistant Escherichia coli in feces from preweaned dairy calves and postpartum dairy cows.
abstract: Quinolone resistance may emerge in gut bacteria (e.g., in Escherichia coli) of animals. Such bacteria could cause infections in the animal itself or be transmitted to humans via the food chain. Quinolone resistance is also observed in fecal E. coli of healthy dairy cattle, but the prevalence varies between farms, not solely as a result of varying degree of fluoroquinolone exposure. The objective of this study was to identify risk factors for the fecal shedding of quinolone-resistant E. coli (QREC) from dairy calves and postpartum cows. Rectal swabs from 15 preweaned calves and 5 postpartum cows per farm were collected on 23 Swedish dairy farms to determine the prevalence of QREC. Risk factors for the shedding of QREC were investigated using multivariable statistical models. Quinolone-resistant E. coli were found on all but one farm. Factors associated with QREC shedding by calves were being younger than 18 d, being fed milk from cows treated with antimicrobials, recent use of fluoroquinolones in the herd, carriage of QREC by postpartum cows, and using the calving area never or rarely as a sick pen compared with often. Factors associated with QREC shedding by cows were calving in group pens or freestalls compared with single pens or tiestalls, purchasing cattle, sharing animal transports with other farmers, and poor farm hygiene. Proper biosecurity and improved hygiene, as well as minimizing fluoroquinolone exposure and waste milk feeding, may be important factors to reduce the burden of QREC on dairy farms.
authors.affiliation: Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89 Uppsala, Sweden; Department of Clinical Sciences, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden. Electronic address: anna.duse@sva.se.
authors.forename: Anna
authors.initials: A
authors.lastname: Duse
authors.affiliation: Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89 Uppsala, Sweden; Department of Clinical Sciences, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.
authors.forename: Karin Persson
authors.initials: KP
authors.lastname: Waller
authors.affiliation: Department of Clinical Sciences, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: Emanuelson
authors.affiliation: Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89 Uppsala, Sweden.
authors.forename: Helle Ericsson
authors.initials: HE
authors.lastname: Unnerstad
authors.affiliation: Växa Sverige, SE-751 05 Uppsala, Sweden.
authors.forename: Ylva
authors.initials: Y
authors.lastname: Persson
authors.affiliation: Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89 Uppsala, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Bengtsson
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle; D003612:Dairying; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development; D005243:Feces / Q000382:microbiology*; D005260:Female; D049590:Postpartum Period / Q000187:drug effects; D015363:Quinolones / Q000494:pharmacology*; D012307:Risk Factors; D014886:Weaning
chemical_list: D000900:Anti-Bacterial Agents; D015363:Quinolones
keywords: calf; postpartum cow; quinolone-resistant Escherichia coli; risk factor