EXPRESS: Oral administration of Enterococcus lactis strain SF68 speeds the recovery of amoxicillin-clavulanate-induced dysbiosis in cats

Objectives: In a previous study, Torres-Henderson et al. (2017), the probiotic Enterococcus lactis strain SF68 was clinically shown to lessen amoxicillin-clavulanate associated diarrhea. The cause or mechanism as to why this clinical benefit occurred, however, was unknown. The cause or mechanism as to why this clinical benefit occurred, however, was not apparent in that study. Since the completion of that work, a new feline dysbiosis index (DI) has been developed and new information concerning the microbiome and bile acid metabolism has been published. The objective of this study was to assess changes in the feline DI and fecal bile acid metabolism to explain how this probiotic lessened amoxicillin-clavulanate-associated diarrhea. Methods: Prospective, randomized, placebo-controlled, double-blinded study. 27 healthy, young, adult, purpose-bred cats were used for a previous study. Cats were randomized into the probiotic (13 cats) or placebo (14 cats) group. Each cat received amoxicillin-clavulanate for 7 days at a standard dose and either the probiotic or placebo for 14 days. Fecal samples from all cats were obtained at baseline, day 7 and day 14. All samples were frozen at -80°C until assessed. Targeted qPCR assays were then used to determine the fecal feline DI and unconjugated fecal bile acid concentrations were measured at each time point. Results: An antibiotic-induced shift in fecal microbiota and unconjugated bile acids was observed, with the probiotic group showing normalization of the feline DI and increased secondary bile acids on Day 14 compared to the placebo group (P = 0.0322). Conclusions and Relevance: The probiotic E. lactis strain SF68 lessened amoxicillin-clavulanate-associated clinical signs of disease at least in part from the positive effects on the selected microbiota and bile acid metabolism. These findings support supplementing this probiotic to cats that have a clinical need for amoxicillin-clavulanate treatment.