The in vitro effect of fructose on the adherence of Escherichia coli in patients with chronic urinary tract infections

Abstract

There have been anecdotal and published reports on the benefits of cranberry juice for the prevention and/or treatment of urinary tract infections. A previous report from our laboratory demonstrated that cranberry juice cocktail (CJC) inhibits the adherence of clinical isolates of "Escherichia coli" to uroepithelial and buccal cells. It was further demonstrated that the urine of individuals ingesting 15 oz. of cranberry juice showed anti-adherent activity. It has been determined that fructose, a carbohydrate present in CJC, is one of two components that is responsible for the anti-adherent properties of the cocktail. To investigate the role of fructose as an anti-adherent agent, this sugar was incubated along with uroepithelial cells and "E.Coli" in the urine of individuals not prone to urinary tract infections and those who experience chronic infections. It was shown that 5% fructose prevents the attachment of "E.coli" to exfoliated epithelial cells in both groups studied. The inhibitory action of fructose on adherence of type 1 fimbriated "E.coli" in normal and chronic patients was 100% and 84%, respectively. A statistical comparison between normal and chronic individuals was performed and it was determined that fructose inhibits bacterial adherence equally in both groups studied. These finding demonstrate that fructose inhibits bacterial adherence and that the activity is exhibited in the urine. It was also demonstrated that bacterial adherence in urine of chronic patients treated with fructose is not statistically significantly different from the bacterial adherence of chronic patients ingesting CJC daily, suggesting that the anti-adherence activity of the juice may be due to fructose. In addition to fructose, the nondialyzable component of CJC was also investigated for its anti-adherent ability. It was observed that dialyzed cranberry juice inhibited bacterial adherence in 84% of normal subjects and 79% of chronic patients. It was further determined that chronic patients ingesting CJC daily are not statistically significantly different from chronic patients whose urine was treated with dialyzed CJC. These finding demonstrate that CJC contains at least two inhibitory components that prevent attachment of "E.coli" expressing type 1 fimbriae and that their actions can be demonstrated in the urine. It was found that the inhibitory effects of the dialyzable component are attributed to fructose. It was observed that the anti-adherent action of fructose in the urine of chronic patients was equivalent to that of chronic patients ingesting cranberry juice. These results suggest a potential use for fructose in the prevention and management of urinary tract infections.