In vitro investigation of molecules involved in Lactobacillus gasseri SBT2055 adhesion to host intestinal tract components.

AIMS: The adhesion ability of Lactobacillus gasseri SBT2055 was investigated in vitro by searching for its adhesion molecules. METHODS AND
RESULTS: Lactobacillus gasseri SBT2055 showed adherence to host components, including two commercially available mucins, Caco-2 epithelial-like cells and the extracellular matrix molecule fibronectin (Fn). Its adhesion rates to host components were generally higher than those of other Lactobacillus strains. We examined sortase-dependent proteins (SDPs) anchored by a sortase enzyme encoded by srtA1. The adhesion rates of an srtA1 disruptant were lower than those of Lact. gasseri SBT2055, and the relative adherences were as follows: two mucins, 43 and 40%; Caco-2, 66% and Fn, 28%. Seven additional gene disruptants were generated to determine the precise SDPs that contribute to adhesion to each component.
CONCLUSIONS: The adhesion ability of Lact. gasseri SBT2055 was superior to those of other Lactobacillus strains. Additionally, four adhesion molecules were newly identified from candidate SDPs. SIGNIFICANCE AND IMPACT OF THE STUDY: Although the contribution of SDPs to adhesion has been reported using sortase gene disruptants, this is the first report to identify the precise SDPs that act as adhesion molecules. Our results will contribute to achieving better understanding of probiotic bacterial adherence.