Efficacy of Selected Live Biotherapeutic Candidates to Inhibit the Interaction of an Adhesive-Invasive Escherichia coli Strain with Caco-2, HT29-MTX Cells and Their Co-Culture

Adherent-invasive Escherichia coli (AIEC) has been implicated as a microbiological factor in the pathogenesis of inflammatory bowel disease (IBD). We evaluated the ability of six live biotherapeutic products (LBPs) to inhibit the interaction of an AIEC strain to three cell lines representing human gut epithelium. Co-inoculation of LBPs with AIEC showed a reduction in adhesion (up to 73%) and invasion of AIEC (up to 89%). Pre-inoculation of LBPs in HT-29-MTX and Caco-2 cells before challenging with AIEC further reduced the adhesion and invasion of the AIEC, with three LBPs showing significantly (p < 0.0001) higher efficiency in reducing the adhesion of AIEC. In co-inoculation experiments, the highest reduction in adhesion (73%) of AIEC was observed in HT-29-MTX cells, whereas the highest reduction in invasion (89%) was seen in HT-29-MTX and the co-culture of cells. Pre-inoculation of LBPs further reduced the invasion of AIEC with highest reduction (97%) observed in co-culture of cells. Our results indicated that whilst there were differences in the efficacy of LBPs, they all reduced interaction of AIEC with cell lines representing gut epithelium. Their efficiency was higher when they were pre-inoculated onto the cells, suggesting their potential as candidates for alleviating pathogenesis of AIEC in patients with IBD.