Adhering Heat-killed Human Lactobacillus acidophilus, Strain LB, Inhibits the Process of Pathogenicity of Diarrhoeagenic Bacteria in Cultured Human Intestinal Cells

Heat — killed L. acidophilus, strain LB, was tested for its ability to adhere in vitro onto human enterocyte — like Caco — 2 and muco — secreting HT29 — MTX cells in culture. The heat — killed LB bacteria exhibited a high adhesive property. A diffuse pattern of adhesion was observed to the undifferentiated cells, the apical brush border of the enterocytic cells, and to the mucus layer that covered the surface of the mucus — secreting cells. The inhibitory effect of heat — killed LB organisms against the human intestinal Caco — 2 cell — adhesion and cell — invasion by a large variety of diarrhoeagenic bacteria was investigated. The following dose — dependent inhibitions were obtained: (i) against the cell — association of enterotoxigenic, diffusely — adhering and enteropathogenic Escherichia coli, Listeria monocytogenes, Yersinia pseudotuberculosis, and Salmonella typhimurium; (ii) against the cell — invasion by enteropathogenic Escherichia coli, Yersinia pseudotuberculosis, Listeria monocytogenes and Salmonella typhimurium.