Abstract: An unknown laboratory strain was identified and named as Bacillus cereus HMPM18123 based on the 16S rRNA gene and conserved protein-coding gene (gyrA and gyrB) sequences combined with virulence genes (nheA, nheB, nheC, hblA, hblC, hblD, becT, cytK and entFM) and biochemical properties. The tolerance of the strain to different temperatures, pH, simulated gastric and intestinal fluid was evaluated as well as its efficacy in alleviating colitis induced by dextran sulfate sodium (DSS) in mice. The results of growth characteristics showed that the strain had good tolerance to high temperature and simulated gastric and intestinal fluid. In addition, the strain improved DSS-induced colitis symptoms in mice such as body mass loss, colon shortening, increased disease activity index (DAI) score, tissue lesions, and up-regulated expression of inflammatory factors.

Key words: Bacillus cereus; conserved protein-coding genes; virulence genes; growth characteristics; inflammatory bowel disease