Intestinal translocation of enterococci requires a threshold level of enterococcal overgrowth in the lumen

Sci Rep. 2019 Jun 20;9(1):8926. doi: 10.1038/s41598-019-45441-3.

Abstract

Enterococci are subdominant members of the human gastrointestinal microbiota. Enterococcus faecalis is generally harmless for healthy individuals, but it can cause a diverse range of infections in immunodeficient or elderly patients with severe underlying diseases. In this study, we analysed the levels of intestinal translocation of indigenous enterococci in C57BL/6, CF-1 and CX3CR1-/- mice upon clindamycin antibiotic-induced dysbiosis. We found that C57BL/6 was the most permissive model for enterococcal translocation and that initiation of E. faecalis translocation coincided with a threshold of enterococcal colonisation in the gut lumen, which once reached, triggered E. faecalis dissemination to deeper organs. We showed that the extent to which E. faecalis clinical strain VE14821 competed with indigenous enterococci differed between the C57BL/6 and CX3CR1-/- models. Finally, using a simplified gnotobiotic model, we observed E. faecalis crossing an intact intestinal tract using intestinal epithelial cells as one route to reach the lamina propria. Our study opens new perspectives for assessing the effect of various immunodeficiencies and for investigating mechanisms underlying enterococcal translocation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Transport
  • CX3C Chemokine Receptor 1 / genetics
  • Enterococcus / growth & development*
  • Gastrointestinal Microbiome*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout

Substances

  • CX3C Chemokine Receptor 1
  • Cx3cr1 protein, mouse