Probiotic Therapy, What is the most Effective Method for Host Protection Against Enteric Pathogen

Background: Prevention of adverse microbial colonization is supposed to be the most important beneficial effect of the gut microflora. Objectives: The aims of the present study were to compare the effect of co-incubation, pre-incubation and supernatant of sixteen probiotic strains on prevention of enteroinvasive E. coli adhesion. Materials and Methods: Probiotic strains were added to Caco-2 cells followed by E. coli in pre-incubation assay. Tested strains and enteroinvasive E. coli were added to cell lines at the same time in co-incubation assay. Finally, enteroinvasive E. coli was treated with bacteria free supernatant of test strains then added to cell line in treatment with bacteria free supernatant assay. Results: This study showed that the most effective assays in prevention of pathogen adherence were treatment with bacteria free supernatant and pre-incubation respectively. Conclusions: The effect of probiotic bacteria by-products on pathogen exclusion may be of more importance in protecting the host. Therefore, gut colonization or at least persistent presence of probiotics may be helpful in infection prevention.