Impact of hospitalization and antimicrobial drug administration on antimicrobial susceptibility patterns of commensal Escherichia coli isolated from the feces of horses

• Published in: Journal of the American Veterinary Medical Association Vol. 228; no. 12; pp. 1909 - 1917
• Main Authors: Dunowska, M, Morley, P.S, Traub-Dargatz, J.L, Hyatt, D.R, Dargatz, D.A
• Format: Journal Article
• Language: English
• Published: United States 15.06.2006
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; Anti-Bacterial Agents - therapeutic use; antimicrobial agents; commensalism; Cross Infection - veterinary; Drug Resistance, Bacterial; Drug Resistance, Multiple, Bacterial; Escherichia coli; Escherichia coli - drug effects; Escherichia coli Infections - drug therapy; Escherichia coli Infections - microbiology; Escherichia coli Infections - veterinary; Escherichia infections; feces; Feces - microbiology; Female; horse diseases; Horse Diseases - drug therapy; Horse Diseases - microbiology; Horses; Hospitalization; Male; Microbial Sensitivity Tests - veterinary; multiple drug resistance; prevalence; strains
• ISSN: 0003-1488; 1943-569X
• DOI: 10.2460/javma.228.12.1909

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, amino-glycosides, 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.