Rat gut microbiota Targeted Locus (Loci)

Colonization prevention is a common function of a stable gut ecosystem. To test the implication of the resident gut microbiota in colonization resistance towards food-borne bacteria, we quantified the fecal abundance of bacteria contained in a fermented milk product (FMP) in rats during and after FMP administration. Repeatedly, certain rats showed a slower clearance of an FMP-strain, Lactococcus lactis (permissive), compared to others (resistant). Gut microbiota analyses showed that permissive rats are enriched in Lachnospiraceae, more susceptible to FMP-induced shifts and less resilient. We observed similar patterns in humans. This phenotype was transferrable to germ-free rats and abolished when L. lactis was deprived of its surface proteins. In conclusion, we showed that colonization resistance applies to certain food-borne strains and that the amplitude of the gut ecosystem response to dietary bacteria relies on the autochnous populations. Future studies will require microbial-based stratifications to explore the effects of probiotics on gut ecosystem.