title: Comparison of antimicrobial resistance in generic Escherichia coil and Salmonella spp. cultured from identical fecal samples in finishing swine.
abstract: The objectives of this study were to investigate the associations between antimicrobial resistance patterns in generic Escherichia coli and Salmonella spp. isolates recovered from identical pen pooled fecal samples, and to evaluate potential clustering of multiple isolates of these organisms within identical fecal samples. Up to 5 generic E. coli (n = 922 isolates) and Salmonella spp. (n = 922 isolates) isolates were obtained from each of 188 pen pooled fecal samples that had been collected from 45 finishing swine farms in Alberta in 2000, and tested for susceptibility to 15 antimicrobials. No isolates of either organism were resistant to 3rd generation cephalosporins or fluoroquinolones, which in Canada are considered antimicrobials of very high importance to human health. Approximately twice as many generic E. coli isolates as Salmonella spp. isolates were resistant to at least 1 antimicrobial. In addition, E. coli isolates showed more multidrug-resistance patterns. No significant association was observed between the resistance phenotypes of Salmonella spp. and E. coli at the fecal sample level. More clustering at the sample level was observed for proportions of antimicrobial resistance (AMR) in Salmonella spp. isolates than E. coli indicating that in future studies it might be sufficient to test fewer than 5 Salmonella spp. isolates per sample.
authors.affiliation: Department of Population Medicine, University of Guelph, Ontario N1G 2W1 vargac@uoguelph.ca
authors.forename: Csaba
authors.initials: C
authors.lastname: Varga
authors.forename: Andrijana
authors.initials: A
authors.lastname: Rajić
authors.forename: Margaret E
authors.initials: ME
authors.lastname: McFall
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Reid-Smith
authors.forename: Anne E
authors.initials: AE
authors.lastname: Deckert
authors.forename: David L
authors.initials: DL
authors.lastname: Pearl
authors.forename: Brent P
authors.initials: BP
authors.lastname: Avery
authors.forename: Sylvia L
authors.initials: SL
authors.lastname: Checkley
authors.forename: Scott A
authors.initials: SA
authors.lastname: McEwen
mesh_terms: D000367:Age Factors; D000416:Alberta; D000818:Animals; D000831:Animals, Newborn; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016000:Cluster Analysis; D015169:Colony Count, Microbial / Q000662:veterinary; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D005243:Feces / Q000382:microbiology*; D005260:Female; D008297:Male; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D015995:Prevalence; D012307:Risk Factors; D012475:Salmonella; D012481:Salmonella Infections, Animal / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D012621:Seasons; D012737:Sex Factors; D013552:Swine; D013553:Swine Diseases / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents