Oral Consumption of Cranberry Juice Cocktail Inhibits Molecular-Scale Adhesion of Clinical UropathogenicEscherichia coli

Abstract

Cranberry juice cocktail (CJC) has been shown to inhibit the formation of biofilm by uropathogenic Escherichia coli. In order to investigate whether the anti-adhesive components could reach the urinary tract after oral consumption of CJC, a volunteer was given 16 oz of either water or CJC. Urine samples were collected at 0, 2, 4, 6, and 8 hours after consumption of a single dose. The ability of compounds in the urine to influence bacterial adhesion was tested for six clinical uropathogenic E. coli strains, including four P-fimbriated strains (B37, CFT073, BF1023, and J96) and two strains not expressing P-fimbriae but exhibiting mannose-resistant hemagglutination (B73 and B78). A non-fimbriated strain, HB101, was used as a control. Atomic force microscopy (AFM) was used to measure the adhesion force between a silicon nitride probe and bacteria treated with urine samples. Within 2 hours after CJC consumption, bacteria of the clinical strains treated with the corresponding urine sample demonstrated lower adhesion forces than those treated with urine collected before CJC consumption. The adhesion forces continued decreasing with time after CJC consumption over the 8-hour measurement period. The adhesion forces of bacteria after exposure to urine collected following water consumption did not change. HB101 showed low adhesion forces following both water and CJC consumption, and these did not change over time. The AFM adhesion force measurements were consistent with the results of a hemagglutination assay, confirming that oral consumption of CJC could act against adhesion of uropathogenic E. coli.

Using Atomic Force Microscopy to Measure Anti-Adhesion Effects on Uropathogenic Bacteria, Observed in Urine after Cranberry Juice Consumption

“…In addition to studies with juice, the urine of volunteers who have consumed CJC has been investigated to determine if anti-adhesive or anti-biofilm compounds remain in urine. We previously reported that AFM adhesion force measurements between uropathogenic E. coli were decreased in the presence of urine from a volunteer who had consumed CJC [18]. In addition, DiMartino et al showed that cranberry juice consumption decreased biofilm development of uropathogenic E. coli in the urine compared with placebo [19,20].…”

“…Bacteria were immobilized to acid-cleaned glass slides using a cross-linking reaction between amine and carboxyl groups [18]. The cleaned glass slides were immersed in 10% 3-aminopropyltrimethoxysilane in methanol for 20 min.…”

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

“…6,7,[12][13][14] The anti-adhesive properties of cranberries are effective against the ubiquitous and comparatively benign E. coli with type-1 fimbriae, as well as against p-fimbriated and antibioticresistant E. coli strains. [14][15][16] Incubation of p-fimbriated E. coli with cranberry juice of neutral pH changes the conformation of surface molecules on p-fimbriae within 2 hours profoundly and the adhesion power gets lost. 17 The conclusion of cranberries as harboring potent anti-adhesive compounds other than fructose had fueled a lively research to identify them.…”

“…This is reasonable, as there is strong evidence for cranberry-restricted A-type PAC as anti-adhesive compounds, sufficient evidence for PAC bioavailability in humans [29][30][31] and the preservation of anti-adhesive activity in the urine after oral ingestion. 14,16 Consequently, recently performed clinical trials have employed cranberry products standardized for their PAC, sometimes even for their A-type PAC content to deliver enough bioactivity to probands or patients. However, the ingested dose of PAC/A-type PAC necessary to inhibit bacterial adhesion in the urine is still unknown.…”

“…Some trials have tentatively incorporated serial measurements of anti-adhesion effects in the urine of patients to ensure bioactivity. 14,38 Cranberry products …”