In vitro anti-adherence effect of probiotic Lactobacillus strains on human enteropathogens

Probiotic bacteria possess great potential for producing antimicrobial substances that inhibit and control pathogenic bacteria in the human gastrointestinal tract. The aim of this study was to determine the anti-adherence properties of the probiotic Lactobacillus strains Lb. rhamnosus ŁOCK 0900, Lb. rhamnosus ŁOCK 0908, and Lb. casei ŁOCK 0919 (individually and in a 1:1:2 mixture) against the reference pathogens Clostridium difficile (ATCC 9689), Enterococcus faecalis (ATCC 29212), Listeria monocytogenes (ATCC 19115), and Staphylococcus aureus (ATCC 6538) using the Caco-2 human colon adenocarcinoma cell line. The mixture of probiotic strains inhibited the adherence of all pathogens, from 10.2% for E. faecalis ATCC 29212 to 97.2% for L. monocytogenes ATCC 19115. Of all the tested probiotic strains, Lb. casei ŁOCK 0919 reduced the adherence of S. aureus ATCC 6538 to the greatest extent (by 45.9%). These results suggest that adherence inhibition may involve competition for eukaryotic cell receptors and probiotic bacteria could protect the host cells from pathogen colonization and disease.