title: Presentation of postweaning Escherichia coli diarrhea in southern Ontario, prevalence of hemolytic E. coli serogroups involved, and their antimicrobial resistance patterns.
abstract: Post-weaning Escherichia coli diarrhea (PWECD) in Ontario was investigated using a case-control study involving 50 Ontario nurseries. The clinical signs and the impact on productive parameters were determined by means of a producer survey. The hemolytic E. coli serogroups involved in PWECD (O149:K91:K88) were examined in this study. Based on a polymerase chain reaction test, the hemolytic E. coli from 82% of the case herds were positive for 3 enterotoxins (STa, STb, and LT), those from 12% of the case herds were positive for STb and LT only, and those from one herd (6%) were positive for 3 enterotoxins, as well as for verotoxin and F18 pili. The E. coli involved in disease were resistant to multiple antibiotics. Case farms commonly used a wide variety of antibiotics either in the feed or water, or as injectable drugs. The most common antibiotic used to treat PWECD on the study farms was apramycin, but evidence of resistance to this antibiotic was noted. The PWECD problem was commonly seen within a week of weaning but onset of diarrhea was reported as late as the grower-finisher stage. Growth rate was poorer in case herds and mortality was higher than in control herds, demonstrating that PWECD is an economically important disease in Ontario.
authors: Department of Population Medicine, Ontario Veterinary College, University of Guelph.
authors: Rocio
authors: R
authors: Amezcua
authors: Robert M
authors: RM
authors: Friendship
authors: Catherine E
authors: CE
authors: Dewey
authors: Carlton
authors: C
authors: Gyles
authors: John M
authors: JM
authors: Fairbrother
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016022:Case-Control Studies; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D024901:Drug Resistance, Multiple, Bacterial; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000187:drug effects / Q000254:growth & development*; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D009864:Ontario / Q000453:epidemiology; D015995:Prevalence; D012703:Serotyping; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000382:microbiology*; D014886:Weaning; D015430:Weight Gain
chemical_list: D000900:Anti-Bacterial Agents