Enterococcus faecalis induces inflammatory bowel disease in interleukin-10 knockout mice

Germ-free interleukin-10 knockout (IL-10 KO) mice developed inflammatory bowel disease (IBD) after they were colonized with a pure culture of Enterococcus faecalis. E faecalis not only induced IBD (primarily in colon and rectum) but rectal dysplasia and adenocarcinoma was also found in the IL-10 KO mice. Conventional (complex-intestinal flora) IL-10 KO mice developed IBD within 10 to 15 weeks of age and showed more pathology in the cecum. (typhlitis) than we observed with E faecalis-induced IBD in gnotobiotic IL-10 KO mice. Conversely, neither germ-free IL-10 mice nor IL-10 KO mice colonized as adults, with a pure culture of Candida albicans, Escherichia coli, Lactobacillus casei, L. reuteri, L. acidophilus, a Bifidobacterium sp, Lactococcus lactis, or a Bacillus sp. developed IBD during the 25- to 30-week study. E faecalis is a common intestinal microbe of man and animals that can trigger IBD, dysplasia, and carcinoma in a genetically susceptible murine host.