Cranberry Products Inhibit Adherence of P-Fimbriated Escherichia Coli to Primary Cultured Bladder and Vaginal Epithelial Cells

Abstract

Purpose-Cranberry proanthocyanidins have been identified as possible inhibitors of Escherichia coli adherence to uroepithelial cells. However, little is known about the dose range of this effect. Furthermore, it has not been studied directly in the urogenital system. To address these issues we tested the effect of a cranberry powder and proanthocyanidin extract on adherence of a P-fimbriated uropathogenic E. coli isolate to 2 new urogenital model systems, namely primary cultured bladder epithelial cells and vaginal epithelial cells.Materials and Methods-E. coli IA2 was pre-incubated with a commercially available cranberry powder (9 mg proanthocyanidin per gm) or with increasing concentrations of proanthocyanidin extract. Adherence of E. coli IA2 to primary cultured bladder epithelial cells or vaginal epithelial cells was measured before and after exposure to these products.Results-Cranberry powder decreased mean adherence of E. coli IA2 to vaginal epithelial cells from 18.6 to 1.8 bacteria per cell (p <0.001). Mean adherence of E. coli to primary cultured bladder epithelial cells was decreased by exposure to 50 μg/ml proanthocyanidin extract from 6.9 to 1.6 bacteria per cell (p <0.001). Inhibition of adherence of E. coli by proanthocyanidin extract occurred in linear, dose dependent fashion over a proanthocyanidin concentration range of 75 to 5 μg/ml.Conclusions-Cranberry products can inhibit E. coli adherence to biologically relevant model systems of primary cultured bladder and vaginal epithelial cells. This effect occurs in a dose dependent relationship. These findings provide further mechanistic evidence and biological plausibility for the role of cranberry products for preventing urinary tract infection. Keywordsbladder; vagina; cranberry; Escherichia coli; urinary tract infections Urinary tract infection is a common bacterial infection in women of all ages, resulting in considerable morbidity and health care costs. A recent population based study showed that † Correspondence and requests for

Recurrent Urinary Tract Infection and Urinary Escherichia coli in Women Ingesting Cranberry Juice Daily: A Randomized Controlled Trial

“…27 In vitro studies have demonstrated this adherence inhibition with proanthocyanidin extract from cranberries, human urine collected after cranberry ingestion, and growth of E coli on cranberry-containing media. 9,27,28 None of these previous in vitro studies longitudinally evaluated clinical outcomes. Similarly, none of the clinical studies correlated observed patient outcomes with in vitro findings.…”

“…5,6 In vitro data have shown that cranberry inhibits primarily P-fimbriated uropathogenic strains of Escherichia coli from adhering to uroepithelial cells, which is a critical step in the development of UTI. [7][8][9] However, these findings have not been correlated directly with clinical outcomes or verified in clinical studies.…”

Cranberry products in the prevention of urinary tract infections: examining the evidence

“…More virulent E. coli causing pyelonephritis and complicated UTI typically bear p-fimbriae in addition to type-1 fimbriae. Adhesion of p-fimbriated E. coli with their specific lectins [9][10][11] is not inhibitable by fructose or other low molecular carbohydrates (hence mannose-resistant fimbriae).…”

Urinary tract infections in the menopausal period: optimal management

“…Taniny te zapobiegają tworzeniu się fimbrii typu P na ścianie bakterii Escherichia coli, hamując w ten sposób możli-wości adhezji drobnoustrojów do komórek urotelium. Blokowanie powstawania fimbrii bakterii odgrywa kluczową rolę w zapobieganiu kolonizacji i jest zależne od dawki proantocyjanidyn [21]. Badanie z randomizacją nad wpływem koncentratu soku żurawinowo-borówko-wego w dawce 50 ml 4 razy dziennie istotnie zmniejszało ryzyko nawrotu infekcji układu moczowego u kobiet [22].…”