Identification of surface proteins involved in the adhesion of a probiotic Bacillus cereus strain to mucin and fibronectin.

Several Bacillus strains isolated from commercial probiotic preparations were identified at the species level, and their adhesion capabilities to three different model intestinal surfaces (mucin, Matrigel and Caco-2 cells) were assessed. In general, adhesion of spores was higher than that of vegetative cells to the three matrices, and overall strain Bacillus cereus(CH) displayed the best adhesion. Different biochemical treatments revealed that surface proteins of B. cereus(CH) were involved in the adhesion properties of the strain. Surface-associated proteins from vegetative cells and spores of B. cereus(CH) were extracted and identified, and some proteins such as S-layer components, flagellin and cell-bound proteases were found to bind to mucin or fibronectin. These facts suggest that those proteins might play important roles in the interaction of this probiotic Bacillus strain within the human gastrointestinal tract.