title: Changes in fecal microbiota of healthy dogs administered amoxicillin.
abstract: The effect of oral amoxicillin treatment on fecal microbiota of seven healthy adult dogs was determined with a focus on the prevalence of bacterial antibiotic resistance and changes in predominant bacterial populations. After 4-7 days of exposure to amoxicillin, fecal Escherichia coli expressed resistance to multiple antibiotics when compared with the pre-exposure situation. Two weeks postexposure, the susceptibility pattern had returned to pre-exposure levels in most dogs. A shift in bacterial populations was confirmed by molecular fingerprinting of fecal bacterial populations using denaturing gradient gel electrophoresis (PCR-DGGE) of the 16S V3 rRNA gene region. Much of the variation in DGGE profiles could be attributed to dog-specific factors. However, permutation tests indicated that amoxicillin exposure significantly affected the DGGE profiles after controlling for the dog effect (P=0.02), and pre-exposure samples were clearly separated from postexposure samples. Sequence analysis of DGGE bands and real-time PCR quantification indicated that amoxicillin exposure caused a shift in the intestinal ecological balance toward a Gram-negative microbiota including resistant species in the family Enterobacteriaceae.
authors.affiliation: Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science (NSVS), 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: Henning
authors.initials: H
authors.lastname: Sørum
authors.forename: Ellen
authors.initials: E
authors.lastname: Skancke
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Yannarell
authors.forename: Roderick I
authors.initials: RI
authors.lastname: Mackie
mesh_terms: D000658:Amoxicillin / Q000008:administration & dosage*; D000818:Animals; D001419:Bacteria / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000235:genetics; D004285:Dogs / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D004755:Enterobacteriaceae / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology*; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology; D008297:Male; D054892:Metagenome / Q000187:drug effects*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D000658:Amoxicillin