Inhibition of the adherence of Escherichia coli strains to basement membrane by Lactobacillus crispatus expressing an S-layer

Aims: This study aimed to evaluate the efficiency with which Lactobacillus crispatus JCM 5810 inhibited the adhesion of enteric pathogens to a synthetic basement membrane and to elucidate the mechanism underlying the inhibition. Methods and Results: Lactobacillus crispatus JCM 5810 inhibited the adhesion of three diarrhoeagenic Escherichia coli strains to a reconstituted basement membrane preparation called Matrigel, used as a model of a damaged intestinal tissue site. Inhibition was also observed with the use of immobilized laminin, a major component of Matrigel, but diminished after the removal of S-layer protein (CbsA) from JCM 5810 cells. The isolated CbsA inhibited the adhesion of E. coli to both Matrigel and immobilized laminin. Lactobacillus crispatus JCM 5810 and CbsA seem to inhibit pathogenic E. coli from adhering to basement membrane via competition with laminin molecules for binding sites. Conclusions: These results suggested that not only Lact. crispatus JCM 5810 cells but CbsA alone might prevent pathogens from colonizing damaged intestinal tissues. Significance and Impact of the Study: This is the first study to show the applied aspect of Lactobacillus S-layer protein.