They observed that the more dangerous E. coli - like bacteria called Citrobacter rodentium flourished more in the guts of mice fed a fiber - free diet. (biomeonboardawareness.com)
The DNA - damaging bacterium is found to flourish in the guts of mice with inflammatory bowel disease, putting them at higher risk for colorectal cancer (scientificamerican.com)
Slack et al. (p. 617) show that Toll - like receptor — dependent signaling is required to maintain compartmentalization of bacteria to the gut of mice. (science.sciencemag.org)