Colonic goblet cell-associated antigen passages mediate physiologic and beneficial translocation of live gut bacteria in preweaning mice

Gut-resident microbes contribute to host health via multiple mechanisms. Some of the most striking gut microbiota induced effects occur in the extraintestinal tissues and are restricted to early life. The mechanisms by which gut residing bacteria induce effects on distant host tissues and why this is restricted to a period in early life are largely unknown. We found that a subset of live gut-resident bacteria spontaneously translocate from gut to extraintestinal tissues in preweaning, but not adult mice. Translocation in preweaning mice appeared physiologic as it did not induce an inflammatory response and was in part controlled by sphingosine-1-phsophate receptor (S1PR) expressing host cells and host goblet cells. One translocating strain, Lactobacillus animalisWU, contained unique coding sequences for genes in the tyrocidine-gramicidin antibiotic-synthesizing gene cluster as well as five other regions putatively producing secondary metabolites with anti-microbial activity. Lactobacillus animalisWU exhibited antimicrobial activity against the late-onset sepsis pathogen E. coli ST69 in vitro, and translocation of L. animalisWU protected preweaning mice from systemic E. coli ST69 sepsis in vivo. These observations demonstrate a previously unappreciated higher-level symbiosis with our gut microbes.