title: Antimicrobial resistance in Escherichia coli strains isolated from Swiss weaned pigs and sows.
abstract: Based on Directive (EC) No 99/2003, monitoring programs on the development of antimicrobial resistance in bacteria from livestock are implemented in many European countries. The aim of the present study was (i) to establish comprehensive baseline data on the antimicrobial resistance situation in Escherichia coli isolates obtained from healthy pigs (pooled fecal samples) originating from 60 Swiss pig-breeding farms, and (ii) to analyze differences in the resistance frequency between Escherichia coli isolates from weaned pigs and sows. Susceptibility testing (disc diffusion method) was performed on 429 isolates from weaned pigs and 431 isolates from sows. Overall, 17.7% of the isolates from weaned pigs and 22.5% of the Escherichia coli isolates from sows were susceptible to all antibiotics tested. Low resistance prevalence was found for amoxicillin, amoxicillin/clavulanic acid, ampicillin, cefquinome, ciprofloxacin, colistin, florfenicol, and gentamicin. The most frequently found resistances were against streptomycin (60.6% of the isolates from weaners and 64.3% of the isolates from sows), sulfonamide (51.5% and 26.9%), tetracycline (35.2% and 22.0%), and trimethoprim (27.5% and 11.1%). With exception of colistin, most resistances were found for those antibiotics commonly used on the farms. Except for ciprofloxacin and streptomycin, isolates from weaned pigs showed higher resistance prevalence than those from sows. This difference was significant for cefquinome, florfenicol, sulfonamide, tetracycline, and trimethoprim (p<0.05).
authors.affiliation: Department of Farm Animals, University of Zurich.
authors.forename: C
authors.initials: C
authors.lastname: Stannarius
authors.forename: E
authors.initials: E
authors.lastname: Bürgi
authors.forename: G
authors.initials: G
authors.lastname: Regula
authors.forename: M A
authors.initials: MA
authors.lastname: Zychowska
authors.forename: C
authors.initials: C
authors.lastname: Zweifel
authors.forename: R
authors.initials: R
authors.lastname: Stephan
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D005260:Female; D008297:Male; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D013552:Swine; D013553:Swine Diseases / Q000188:drug therapy* / Q000382:microbiology; D013557:Switzerland; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents