CONICET | Buscador de Institutos y Recursos Humanos

Adhesive interaction of many probiotic bacteria with epithelial mucosa from ileum and colonic tissue has been described but only few reports on bacteria using stomach epithelia for persistent adhesion are available. This report describes the adhesive interaction of Streptococcus (S.) thermophilus CRL1190 with gastric mucosa in different in situ and in vitro assays. The adhesion of the probiotic bacteria was observed in vivo model by using experimental gastritis model in Balb/C mice treated for 7 days with fermented milk FM1190. The present study was undertaken to evaluate in situ the mode of adhesion of the strain to human stomach tissue sections. The FITClabeled S. thermophilus CRL1190 was attached to different parts of the tissue, the EPS1190 seemed to have not a key role in adhesion. Studies in vitro were carried out by using different echniques like confocal laser scanning microscopy (CLSM) and flow cytometry (FACS). In vitro adhesion of FITC‐labeled S. thermophilus CRL1190 on AGS cells, as imaged by laser scanning microscopy and quantified by flow cytometry, proved that bacterial adhesion was mainly due to the MOI (multiplicity of infection) instead of being mediated by the EPS1190 polysaccharide. From these data, the strong adhesion of S. thermophilus CRL1190 to gastric mucosa (in vivo model) may be attributed to the tridimensional mesh and biofilm which is attached to the epithelial surface but it was observed that the bacteria could attach to the gastric cell surface (in vivo assays) even in the absence of EPS1190. According to these results, it is possible to assume that S. thermophilus CRL1190 has the ability to attach to the gastric mucosa tissue and in this way exerts its probiotic effects by reducing the inflammation conditions produced during gastritis.