Use of a Fluorometric Microplate Assay to Assess the Activity of Prebiotics and Probiotics against Uropathogenic E. coli Adherence to Human Uroepithelial Cells

Abstract

Urinary tract infections impact ~40-50% of women in the US. Probiotics have gained interest as an alternative treatment as they may compete with pathogens for adherence and colonization of mucosal surfaces. We used a fluorometric microplate assay to determine the ability of prebiotics and probiotics to inhibit E. coli adherence to human uroepithelial cells (UEC). Probiotic bacteria and p-fimbriated E. coli were labeled for 30 min with 400 μM BacLight Red or Green; E. coli adherence to UEC was measured after pre- (exclusion), co- (competition), and post-incubation (displacement) of probiotics with UEC. Probiotics inhibited E. coli adherence in a dose dependent manner. B. infantis reduced E. coli adherence up to 80, 77, and 27% for exclusion, competition, and displacement. In addition, L. plantarum reduced E. coli adherence up to 62, 70, and 41% and L. rhamnosus GR-1 inhibited E. coli adherence up to 45, 61, and 25% for exclusion, competition, and displacement, respectively. Incubation of probiotics with fructooligosaccharides, inulin, and pectin further reduced E. coli adherence; however, these prebiotics did not increase probiotic adherence to UEC. Probiotics inhibited the adherence of uropathogenic E. coli to human UEC; the addition of prebiotics further promoted this anti-E. coli adhesion activity, but did not increase probiotic adherence to UEC. Therefore, probiotics may produce metabolites that are inhibitory to urinary tract pathogens. Supported by the ARC, Washington State University.