title: Impact of hospitalization and antimicrobial drug administration on antimicrobial susceptibility patterns of commensal Escherichia coli isolated from the feces of horses.
abstract: Objective-To evaluate antimicrobial susceptibility of commensal Escherichia coli strains isolated from the feces of horses and investigate relationships with hospitalization and antimicrobial drug (AMD) administration. Design-Observational study. Animals-68 hospitalized horses that had been treated with AMDs for at least 3 days (HOSP-AMD group), 63 hospitalized horses that had not received AMDs for at least 4 days (HOSP-NOAMD group), and 85 healthy horses that had not been hospitalized or treated with AMDs (community group). Procedures-Fecal samples were submitted for bacterial culture, and up to 3 E coli colonies were recovered from each sample. Antimicrobial susceptibility of 724 isolates was evaluated. Prevalence of resistance was compared among groups by use of log-linear modeling. Results-For 12 of the 15 AMDs evaluated, prevalence of antimicrobial resistance differed significantly among groups, with prevalence being highest among isolates from the HOSP-AMD group and lowest among isolates from the community group. Isolates recovered from the HOSP-AMD and HOSP-NOAMD groups were also significantly more likely to be resistant to multiple AMDs. Resistance to sulfamethoxazole and resistance to trimethoprim-sulfamethoxazole were most common, followed by resistance to gentamicin and resistance to tetracycline. Use of a potentiated sulfonamide, aminoglycosides, cephalosporins, or metronidazole was positively associated with resistance to 1 or more AMDs, but use of penicillins was not associated with increased risk of resistance to AMDs. Conclusion and Clinical Relevance-Results suggest that both hospitalization and AMD administration were associated with prevalence of antimicrobial resistance among E coli strains isolated from the feces of horses.
authors.affiliation: Animal Population Health Institute, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Dunowska
authors.forename: Paul S
authors.initials: PS
authors.lastname: Morley
authors.forename: Josie L
authors.initials: JL
authors.lastname: Traub-Dargatz
authors.forename: Doreene R
authors.initials: DR
authors.lastname: Hyatt
authors.forename: David A
authors.initials: DA
authors.lastname: Dargatz
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D003428:Cross Infection / Q000662:veterinary; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000187:drug effects*; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D005260:Female; D006734:Horse Diseases / Q000188:drug therapy* / Q000382:microbiology; D006736:Horses; D006760:Hospitalization; D008297:Male; D008826:Microbial Sensitivity Tests / Q000662:veterinary
chemical_list: D000900:Anti-Bacterial Agents