Adhesion of three Lactobacillus strains to human urinary and intestinal epithelial cells

Three strains of urogenital lactobacilli were found to adhere in phosphate buffered saline to human uroepithelial cells in vitro according to thermodynamic principles, and to adhere in culture medium to intestinal cells with no such correlation. The most hydrophilic strain (water contact angle 54 degrees) L. casei RC-17 was the most adherent to uroepithelial (118 bacteria per cell) and intestinal cells (165 bacteria per cell). A direct correlation was found between bacterial hydrophilicity and adhesion to uroepithelial cells for the three strains tested. An extracellular adhesin, which appeared to be proteinaceous, and a trypsin-insensitive cell wall adhesin were identified. It was evident that high levels of bacterial retention could be reproduced in vitro, perhaps indicating the potential colonizing capacity of these strains in vivo.