title: Fecal microbiota of horses in the clinical setting: potential effects of penicillin and general anesthesia.
abstract: Antimicrobial treatment is associated with the spread of antimicrobial resistance and disturbances in the ecological balance of intestinal microbiota. In horses, the main adverse effect of antimicrobial treatment is colitis. We used culture and 16S rRNA gene based molecular methods to monitor the prevalence of antimicrobial resistance and changes in predominant fecal populations during penicillin treatment and general anesthesia of horses in the clinical setting. After 5 days of parenteral administration of penicillin, fecal Escherichia coli were resistant to multiple unrelated antimicrobial agents when compared to the pre-exposure situation. Denaturing gradient gel electrophoresis (DGGE) profiles indicated that horses have an extremely diverse fecal microbiota, with marked differences between individual horses. Most of the variation in DGGE profiles could be attributed to horse-specific factors, and penicillin, general anesthesia or both could not explain the remaining variation. Within-animal variation remained less than between-animal variation despite treatment. However, real-time PCR quantification (qPCR) indicated subclinical changes in selected bacterial groups of the penicillin treated horses.
authors.affiliation: Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Oslo, Norway. anne.mette.gronvold@veths.no
authors.forename: Anne-Mette R
authors.initials: AM
authors.lastname: Grønvold
authors.forename: Trine M
authors.initials: TM
authors.lastname: L'Abée-Lund
authors.forename: Eric
authors.initials: E
authors.lastname: Strand
authors.forename: Henning
authors.initials: H
authors.lastname: Sørum
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Yannarell
authors.forename: Roderick I
authors.initials: RI
authors.lastname: Mackie
mesh_terms: D000768:Anesthesia, General / Q000662:veterinary*; D000818:Animals; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D058645:Denaturing Gradient Gel Electrophoresis / Q000662:veterinary; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005243:Feces / Q000382:microbiology*; D006736:Horses / Q000382:microbiology* / Q000502:physiology; D007422:Intestines / Q000382:microbiology* / Q000502:physiology; D008297:Male; D054892:Metagenome / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D010406:Penicillins / Q000494:pharmacology*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012336:RNA, Ribosomal, 16S / Q000737:chemistry / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D010406:Penicillins; D012336:RNA, Ribosomal, 16S