GI09 - Effect of a Prokinetic Dose of Erythromycin on the Canine Fecal Microbiome and Bile Acids

Abstract:

Background: Erythromycin has an established prokinetic effect at sub-antimicrobial doses in dogs; however, antibiotics can negatively impact the fecal microbiome and metabolome.

Objectives: To prospectively evaluate effects of erythromycin at a prokinetic dose on the fecal microbiome and fecal bile acids over time.

Animals: Twelve healthy adult research dogs.

Methods: Dogs received erythromycin (1mg/kg PO q8h) for 8 days and then were monitored for 35 days. Feces were collected before (day 1), during (day 6), and after erythromycin administration (days 11, 26, 36, 45), and scored daily. The microbiome was assessed using qPCR to determine the abundance of 16 core bacterial taxa and the Dysbiosis Index (DI) was calculated. Fecal concentrations of conjugated and unconjugated bile acids (UBAs) were measured on collection days.

Results: Fecal scores did not significantly change. The abundances of several bacterial taxa (7/16) were significantly decreased on day 6 and/or day 11, including Peptacetobacter hiranonis (p = 0.007); however, despite statistical significance, the majority of dogs remained within the provided reference ranges, when available. All taxa returned to baseline by day 45. Overall, the percentage of primary UBAs was not significantly altered at any time point. However, 5 of 12 dogs demonstrated increased primary UBA percentages (>60%) on day 6, which normalized in all dogs by day 36.

Conclusions: Erythromycin administered at a prokinetic dose was associated with subtle and transient alterations in the canine fecal microbiome; however, a subset of dogs exhibited reversible dysbiosis characterized by changes in fecal bile acid metabolism.