BACKGROUND: The inhibition of Escherichia coli growth in the presence of Vaccinium macrocarpon has been extensively described; however, the mechanisms of this activity are not well characterized.

FINDINGS: Here, E. coli was grown in media spiked with cranberry juice. The growth rate and media pH were monitored over more than 300 generations. The pH of the growth media was found to decrease during cell growth. This result was unique to media spiked with cranberry juice and was not reproduced through the addition of sugars, proanthocyanidins, or metal chelators to growth media.

CONCLUSION: This study demonstrated that factors other than sugars or proanthocyanidins in cranberry juice result in acidification of the growth media. Further studies are necessary for a complete understanding of the antimicrobial activity of cranberry products.

An ethanolic extract of Cranberry exerted a significant antimicrobial effect on Saccharomyces bayanus and Pseudomonas fluorescens. The antimicrobial properties of cranberries were due to a number of factors. First, the low pH (2.6) inhibited many microorganisms per se, and its effect on the dissociation of benzoic acid made the inhibition more drastic. Secondly, after raising the pH to 5.2, cranberry juice still did not support the growth of S. bayanus. Growth did occur at pH 5.2 after 0.3% yeast nitrogen base was added. Thirdly, proanthocyanidins and flavonols were found to be the major microbial inhibitors other than benzoic acid. The results showed that proanthocyanidins provided 21.3% of the inhibition, the flavonols 18.5% and benzoic acid 15.6%.

Cranberry juice has developed a following as a simple, nonpharmacologic means to reduce or treat urinary tract infections, yet the scientific basis for such a claim has been lacking. A new study suggests that bacterial infections (bacteriuria) and associated influx of white blood cells into the urine (pyuria) can be reduced by nearly 50% in elderly women who drink 300 mL of cranberry juice cocktail each day over the course of a 6-month study. The results of this study suggest that consumption of cranberry juice is more effective in treating than preventing bacteriuria and pyuria. Along with earlier reports on the ability of cranberry juice to inhibit bacterial adherence to urinary epithelial cells in cell culture, this new work suggests that drinking cranberry juice each day may be clinically useful. Additional work must be conducted, however, to more completely define the efficacy of cranberry juice.

OBJECTIVES: To determine the safety, tolerability, maximal tolerated dose, and efficacy of a concentrated cranberry liquid blend, UTI-STAT with Proantinox, in female patients with a history of recurrent urinary tract infections (rUTIs).

METHODS: The study agent was administered orally at 15, 30, 45, 60, and 75 mL daily for 12 weeks to women with a history of 2.78 ± 0.73 rUTIs 6 months. Blood and urine samples were collected at baseline and weeks 4 and 12. The women took daily doses of the agent. The primary endpoints were the safety, tolerability, and maximal tolerated dose. The secondary endpoints were the efficacy with regard to rUTI and quality-of-life (QOL) symptoms.

RESULTS: A total of 28 subjects were included in the study. Of these 28 women, the data from 23 were analyzable. The average age was 46.5 ± 12.8 years. The maximal tolerated dose of UTI-STAT was 75 mL/d, and the recommended dose was set at 60 mL/d. The secondary endpoints demonstrated that only 2 (9.1%) of 23 reported a rUTI, a markedly better rate than the historical data. At 12 weeks, the reduction in worry about rUTIs and increased QOL with regard to the physical functioning domain and role limitations from physical health domain, as measured by the Medical Outcomes Study short-form 36-item questionnaire, were significant (P = .0097). A lower American Urological Association Symptom Index indicating greater QOL was also significant (P = .045).

CONCLUSIONS: The novel concentrated cranberry liquid blend showed a good safety profile and tolerability in both pre- and postmenopausal women with history of rUTIs. The secondary endpoints demonstrated its effectiveness in reducing the incidence of rUTI and increasing QOL. Given this evidence, supplementation might be beneficial in the prevention of rUTIs in this population.

In this study, urine was collected from groups of volunteers following the consumption of water, ascorbic acid, or cranberry supplements. Only ascorbic acid intake consistently produced acidic urine. Photospectroscopy data indicated that increased water consumption produced urine with lower protein content. Surface tension measurements of the collected urine showed that both water and cranberry supplementation consistently produced urine with surface tensions higher than the control or urine collected following ascorbic acid intake. These urine samples were also employed to study uropathogen adhesion to silicone rubber in a parallel plate flow chamber. Urine obtained after ascorbic acid or cranberry supplementation reduced the initial deposition rates and numbers of adherent Escherichia coli and Enterococcus faecalis, but not Pseudomonas aeruginosa, Staphylococcus epidermidis, or Candida albicans. Conversely, urine obtained from subjects with increased water intake vastly increased the initial deposition rates and numbers of adherent E. coli and E. faecalis (P 0.05).

The objective of the study was to evaluate liquid cranberry products as prophylaxis against bacterial urinary tract infection in a pediatric neuropathic bladder population. Forty cases managed by clean intermittent catheterization with or without pharmacotherapy were enrolled in a randomized single-blind cross-over study. Subjects ingested 15 mL/kg/day of cranberry cocktail or water for six months followed by the reverse for another six months. Initial catheter urine samples and subsequent monthly and interim cultures were obtained. Associated symptoms were recorded along with follow-up attendance/compliance registry. The number of negative culture months to the number of months contributed was tabulated and compared between interventions. Individual, cumulative and antimicrobial subset analysis was performed. Twenty one patients completed the study;12 dropped out for reasons related to the cranberry (taste, caloric load and cost); seven patients dropped out for other reasons (parents too busy, death, no stated reason). Wilcoxon matched-pairs Signed-ranks analysis revealed no difference between intervention periods (2-tailed P=.5566 [whole group]; p=.2845 [antimicrobial subset]) with respect to infection. Fewer infections were observed in nine patients taking cranberry juice and in nine patients given water; no difference was noted in three. Liquid cranberry products, on a daily basis, at the dosage employed, did not have any effect greater than that of water in preventing urinary tract infections in this pediatric neuropathic bladder population.

No abstract

STUDY DESIGN: A pilot study of 15 spinal cord injured patients. Objective: To determine whether alteration of fluid intake and use of cranberry juice altered the bacterial biofilm load in the bladder. SETTING: London, Ontario, Canada. METHODS: Urine samples were collected on day 0 (start of study), on day 7 following each patient taking one glass of water three times daily in addition to normal diet, and on day 15 following each patient taking one glass of cranberry juice thrice daily. One urine sample was sent for culture and a second processed to harvest, examine by light microscopy and Gram stain non-squamous uroepithelial cells to generate bacterial adhesion per 50 cells data. RESULTS: The results showed that cranberry juice intake significantly reduced the biofilm load compared to baseline (P=0.013). This was due to a reduction in adhesion of Gram negative (P=0.054) and Gram positive (P=0.022) bacteria to cells. Water intake did not significantly reduce the bacterial adhesion or biofilm presence. CONCLUSION: The findings provide evidence in support of further, larger clinical trials into the use of functional foods, particularly cranberry juice, to reduce the risk of UTI in a patient population highly susceptible to morbidity and mortality associated with drug resistant uropathogens

No abstract - Methods: We tested a 5-fold concentrated preparation of the juice to simulate the cranberry concentrate currently available commercially. The concentrate was diluted 1:1 with trypticase soy broth and adjusted to a pH of 7.0 to ensure that the results would not be confounded by the acidity of the medium. We added an inoculum of approximately 104 colony-forming units per milliliter from an overnight culture of a variety of American Type Culture Collection–quality control strains both to plain broth and the broth to which the cranberry juice had been added. Both cultures were incubated at 35°C and bacterial counts performed in duplicate at 90 minutes and 24 hours.