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.

定植抵抗（colonization resistance）是稳定肠道生态系统的常见功能之一。为探究肠道常驻菌群在抵御食源性细菌（food-borne bacteria）定植抵抗中的作用，我们在大鼠摄入发酵乳制品（fermented milk product, FMP）期间及摄入后，定量检测了粪便中该发酵乳制品所含细菌的丰度。实验反复观察到，部分大鼠对一株发酵乳制品来源的乳酸乳球菌（Lactococcus lactis，易感型）的清除速度慢于其他大鼠（抵抗型）。肠道菌群分析显示，易感型大鼠的肠道菌群中毛螺菌科（Lachnospiraceae）富集程度更高，对发酵乳制品诱导的菌群改变更敏感，且恢复能力更弱。我们在人类受试者中也观察到了类似的现象。该表型可移植至无菌大鼠（germ-free rats）体内，且当乳酸乳球菌的表面蛋白被去除后，该表型会消失。综上，我们证实定植抵抗对部分食源性菌株有效，且肠道生态系统对膳食来源细菌的响应幅度取决于肠道固有菌群。未来的研究需基于菌群分层策略，以探究益生菌对肠道生态系统的影响。