We have developed an innate immune model of colitis that occurs in the absence of adaptive immunity, is early-onset, 100% penetrant, chronic, and dependent on microbes. villin-TNFAIP3 transgenic mice, crossed to RAG1-/- mice (aka TRAG mice) develop innate immune-mediated colitis that is not observed in villin-TNFAIP3 or RAG1-/- littermates. Antibiotic treatment prevents colitis in TRAG mice. Thus, we sought to investigate the microbes that drive chronic innate immune colitis in the absence of adaptive immunity.