Effect of cranberry drink on bacterial adhesion in vitro and vaginal microbiota in healthy females.

INTRODUCTION/OBJECTIVE: Cranberries have been shown to produce urinary metabolites that influence uropathogen adhesion and prevent urinary tract infections. This study was designed to determine if consuming reconstituted, unsweetened cranberry drink from extract retained its bioactive properties by reducing uropathogen adhesion without adversely affecting urinary calcium, magnesium and the vaginal microflora.

MATERIALS AND METHODS

A randomized crossover study was undertaken in 12 healthy women consuming reconstituted unsweetened cranberry drink, CranActin or water. The urine was collected at 4 hours and 1 week of consumption and evaluated for antiadhesive properties and urinary pH, calcium and magnesium. Vaginal swabs were collected after 1 week of treatment to assess the vaginal microbiota by DGGE.

RESULTS

The resultant urine produced by subjects who consumed 500 ml reconstituted cranberry extract twice per day, significantly reduced the adherence to epithelial cells of P-fimbriated uropathogenic Escherichia coli and showed a tendency towards significance for two E. coli strains expressing fimbriae and an Enterococcus faecalis isolate. The cranberry drink treatment did not alter urinary pH, but reduced calcium and magnesium concentrations compared to water, although not to statistical significance. The reconstituted cranberry drink had no apparent detrimental effect on the vaginal microbiota. However, consuming twice daily resulted in an apparent loss of a potential pathogen from the vagina in 42% subjects.

CONCLUSIONS

The present findings suggest that reconstituted cranberry drink may retain the ability to reduce the risk of UTI by inhibiting pathogen adhesion while not detrimentally affecting urinary pH or vaginal microbiota, or the risk of calculi.