Cranberry-derived phenolic metabolites and Lactobacilli in the prevention of urinary tract infections. Anti-adhesive activity against uropathogens

Abstract

Urinary tract infections (UTI), one of most common infections worldwide, face increasing antibiotic resistance and high recurrence rates. Consumption of cranberry (Vaccinium macrocarpon) has been widely recommended for prophylaxis against UTIs. Also, probiotic bacteria, especially of the genus Lactobacillus, are regarded as a promising preventive and/or treatment therapy against these infections. Considering that adherence of pathogens to uroepithelial cell receptors seems to be a main step in the pathogenesis of UTI, in this work we have studied the anti-adhesive activity against uropathogens of some cranberry-derived phenolic metabolites as well as some Lactobacillus strains. Following a previously-optimized methodology, we found that some metabolites such as hippuric acid, α-hydroxyhippuric acid and dihydrocaffeic acid 3-O-sulfate, all found in urine after cranberry intake, inhibited the adherence of both Gram-negative (i.e., Escherichia coli ATCC® 53503TM and E. coli DSM 10791), and Gram-positive (i.e., Enterococcus faecalis 04-1) bacteria to bladder cells at physiological relevant concentrations. On the other hand, the Lactobacillus strains with previous in vivo evidence of beneficial effects against UTIs (L. salivarius UCM572 and L. acidophilus 01) significantly inhibited the adherence of all the uropathogens tested. Contrary, L. plantarum CLC17, a strain with no expected effects on UTIs, showed almost negligible anti-adherence effects. In summary, this work demonstrates the anti-adhesive capacity of cranberry-derived microbial metabolites and some Lactobacillus strains against uropathogens in epithelial bladder cells in vitro, confirming that this may be one of the mechanisms involved in the potential preventive effects of cranberries and/or probiotics against UTI.