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Urinary Tract Health and Antibacterial Benefits: In-Vitro

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The antimicrobial effects of cranberry against Staphylococcus aureus

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Authors
Lian PY, Maseko T, Rhee M, Ng K.
Journal
Food Sci Technol Int 18(2):179-86
Abstract

The antimicrobial effects of the American cranberry (Vaccinium macrocarpon) on a major food-borne pathogen, Staphylococcus aureus, were investigated using commercially obtained Lakewood® organic cranberry juice and Ocean Spray® cranberry juice cocktail and four other berry fruit extracts (acai berry, strawberry, raspberry, and blueberry). The results showed that cranberry is a potent antimicrobial against S. aureus and the most potent among the berries studied. The order of percentage inhibition of bacterial growth at the same concentration of phenolic materials as gallic acid equivalents was Lakewood cranberry juice > Ocean Spray cranberry juice ≫ blueberry > acai berry ≫ raspberry ≫ strawberry. The antimicrobial effect was not due to the acidity of the berries as NaOH-neutralized samples were almost as effective in terms of percentage inhibition of viable cell growth. Solid-phase extraction of cranberry juice using C18 solid phase showed that the antimicrobial effects reside exclusively with the C18-bound materials.

Inhibition of Adhesion of Uropathogenic Escherichia coli Bacteria to Uroepithelial Cells by Extracts from Cranberry

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Authors
Ermel G, Georgeault S, Inisan C, Besnard M
Journal
J Med Food 15(2):126-34
Abstract

ABSTRACT Cranberry extract has been reported as a therapeutic agent, mainly in urinary tract infections due to its antiadhesive capacity. In order to compare the effects of proanthocyanidin (procyanidin) (PAC)-standardized cranberry extracts and commercial PAC A2, we first investigated the presence of genes encoding known adhesins on 13 strains of uropathogenic strains coming from patients with cystisis. After this characterization, the anti-adhesive effects of PAC A2 were assayed on selected uropathogenic Escherichia coli strains before testing cranberry extracts. Before checking inhibitory effect on bacterial adhesion to cells, we showed that neither PAC A2 or three cranberry extracts (A, B, and C) specifically inhibited the growth and did not supply any potential nutrient to E. coli strains, including the unrelated control strain. PAC A2 exhibited an inhibitory effect on the adhesion of two selected uropathogenic strains of E. coli. This work also showed that a preliminary exposure of bacteria to PAC A2 significantly reduced the adhesion. This phenomenon has been also observed with a lesser impact when uroepithelial cells were pretreated with PAC A2. Moreover, the assays were more robust when bacteria were in fast growing conditions (exponential phase): the adhesion to uroepithelial cells was greater. Significant reduction of adhesion to urepithelial cells was observed: around 80% of inhibition of adhesion with the cranberry extracts at equivalent PAC concentration of 50 µg/mL. The effects of the different assayed extracts were not obviously different except for extract B, which inhibited approximately 55% of adhesion at an equivalent PAC concentration of 5 µg/mL

Proanthocyanidin-rich Extracts from Cranberry Fruit ( Vaccinium macrocarpon Ait.) Selectively Inhibit the Growth of Human Pathogenic Fungi Candida spp. and Cryptococcus neoformans.

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Authors
Patel KD. Scarano FJ. Kondo M. Hurta RA. Neto CC.
Journal
J Agric Food Chem 59(24):12864-73
Abstract

Cranberry ( Vaccinium macrocarpon ) has been shown in clinical studies to reduce infections caused by Escherichia coli and other bacteria, and proanthocyanidins are believed to play a role. The ability of cranberry to inhibit the growth of opportunistic human fungal pathogens that cause oral, skin, respiratory, and systemic infections has not been well-studied. Fractions from whole cranberry fruit were screened for inhibition of five Candida species and Cryptococcus neoformans , a causative agent of fungal meningitis. Candida glabrata , Candida lusitaniae , Candida krusei , and Cryptococcus neoformans showed significant susceptibility to treatment with cranberry proanthocyanidin fractions in a broth microdilution assay, with minimum inhibitory concentrations as low as 1 mug/mL. MALDI-TOF MS analysis of subfractions detected epicatechin oligomers of up to 12 degrees of polymerization. Those containing larger oligomers caused the strongest inhibition. This study suggests that cranberry has potential as an antifungal agent.

The effect of nondialyzable material (NDM) cranberry extract on formation of contact lens biofilm by Staphylococcus epidermidis

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Authors
Leshem R, Maharshak I, Ben Jacob E, Ofek I, Kremer I
Journal
Invest Ophthalmol Vis Sci 52(7):4929-34
Abstract

PURPOSE: To assess the effects of NDM from cranberries on Staphylococcus epidermidis biofilm formed on soft contact lenses.

METHODS: Soft contact lenses were incubated in Tryptic Soy Broth (TSB) together with S. epidermidis (ATCC35984/RP62A) and various concentrations of NDM, and inspected by scanning electron and confocal microscopy. The TSB was collected after sonification and monitored turbidometrically.

RESULTS: NDM at >=500 mug/mL concentration caused a significant (P 0.01) reduction of biofilm. Scanning electron microscopy of biofilm in the presence of 500 to 1000 mug/mL NDM confirmed these results. In control lenses, multilayered mushroom-shaped biofilm and complete coverage of the lens surface were seen, whereas after incubation with 500 mug NDM per mL TSB, the biofilm was thinner with smaller protuberances, and exposed lens surface was partially seen. In samples incubated with 1000 mug NDM per mL TSB, the lens surface was clearly seen between sporadic microcolonies.

CONCLUSIONS: NDM reduces formation of biofilm on soft contact lenses. This has important implications for the prevention of contact lens-related corneal infections caused by S. epidermidis.

The swarming motility of Pseudomonas aeruginosa is blocked by cranberry proanthocyanidins and other tannin-containing materials

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Authors
O'May C, Tufenkji N
Journal
Appl Environ Microbiol 77(9):3061-7
Abstract

Bacterial motility plays a key role in the colonization of surfaces by bacteria and the subsequent formation of resistant communities of bacteria called biofilms. Derivatives of cranberry fruit, predominantly condensed tannins called proanthocyanidins (PACs) have been reported to interfere with bacterial adhesion, but the effects of PACs and other tannins on bacterial motilities remain largely unknown. In this study, we investigated whether cranberry PAC (CPAC) and the hydrolyzable tannin in pomegranate (PG; punicalagin) affected the levels of motilities exhibited by the bacterium Pseudomonas aeruginosa. This bacterium utilizes flagellum-mediated swimming motility to approach a surface, attaches, and then further spreads via the surface-associated motilities designated swarming and twitching, mediated by multiple flagella and type IV pili, respectively. Under the conditions tested, both CPAC and PG completely blocked swarming motility but did not block swimming or twitching motilities. Other cranberry-containing materials and extracts of green tea (also rich in tannins) were also able to block or impair swarming motility. Moreover, swarming bacteria were repelled by filter paper discs impregnated with many tannin-containing materials. Growth experiments demonstrated that the majority of these compounds did not impair bacterial growth. When CPAC- or PG-containing medium was supplemented with surfactant (rhamnolipid), swarming motility was partially restored, suggesting that the effective tannins are in part acting by a rhamnolipid-related mechanism. Further support for this theory was provided by demonstrating that the agar surrounding tannin-induced nonswarming bacteria was considerably less hydrophilic than the agar area surrounding swarming bacteria. This is the first study to show that natural compounds containing tannins are able to block P. aeruginosa swarming motility and that swarming bacteria are repelled by such compounds.

Effect of juice processing on cranberry antibacterial properties

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Authors
Cote J, Caillet S, Dussault D, Sylvain JF, Lacroix M
Journal
Food Res Int 44: 9, 2922-2929
Abstract

The effects of the industrial juice process on the ability of neutralized cranberry samples and extracts (polar, apolar and anthocyanins) to inhibit the growth of Enterococcus faecium resistant to vancomycin (ERV), Escherichia coli O157:H7 EDL 933, E. coli ATCC 25922, Listeria monocytogenes HPB 2812, Pseudomonas aeruginosa ATCC 15442, Salmonella Typhimurium SL1344 and Staphylococcus aureus ATCC 29213 were investigated. The juice process appeared to have a general enhancing effect on the antibacterial properties of cranberry polar and anthocyanin extracts. The lowest minimum inhibitory concentrations (MICs) (1.80-7.0 micro g phenol/well) were obtained when S. aureus, S. Typhimurium, and ERV were exposed to the juice concentrate. The growth of P. aeruginosa, L. monocytogenes, E. coli ATCC, and E. coli O157:H7 was not inhibited by the juice concentrate, but did show sensitivity (maximal tolerated concentrations of 0.007-0.4 micro g phenol/well). The lowest MICs (22.6-90.5 micro g phenol/well) for P. aeruginosa, S. aureus, S. Typhimurium, and ERV were observed when they were exposed to the cranberry anthocyanin extract obtained from cranberry pomace. The results also showed a negative effect of the juice process on the antibacterial properties of the cranberry apolar extracts: the one obtained from frozen cranberries was most efficient against P. aeruginosa, S. aureus, L. monocytogenes and S. Typhimirium (MIC of 45.50 micro g phenol/well). The tested bacteria showed the greatest resistance toward the cranberry extracts obtained from the mash and the macerated and depectinized mash

Induction of a state of iron limitation in uropathogenic Escherichia coli CFT073 by cranberry-derived proanthocyanidins as revealed by microarray analysis

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Authors
Hidalgo G, Ponton A, Fatisson J, O'May C, Asadishad B, Schinner T, Tufenkji N.
Journal
Appl Environ Microbiol 77(4):1532-5.
Abstract

Transcriptional profiles of uropathogenic Escherichia coli CFT073 exposed to cranberry-derived proanthocyanidins (PACs) were determined. Our results indicate that bacteria grown on media supplemented with PACs were iron deprived. To our knowledge, this is the first time that PACs have been shown to induce a state of iron limitation in this bacterium.

Inhibition of Escherichia coli CFT073 fliC expression and motility by cranberry materials.

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Authors
Hidalgo G, Chan M, Tufenkji N
Journal
Appl Environ Microbiol 77(19):6852-7
Abstract

In humans, uropathogenic Escherichia coli (UPEC) is the most common etiological agent of uncomplicated urinary tract infections (UTIs). Cranberry extracts have been linked to the prevention of UTIs for over a century; however, a mechanistic understanding of the way in which cranberry derivatives prevent bacterial infection is still lacking. In this study, we used a fliC-lux reporter as well as quantitative reverse transcription-PCR to demonstrate that when UPEC strain CFT073 was grown or exposed to dehydrated, crushed cranberries or to purified cranberry-derived proanthocyanidins (cPACs), expression of the flagellin gene (fliC) was inhibited. In agreement with these results, transmission electron microscopy imaging of bacteria grown in the presence of cranberry materials revealed fewer flagella than those in bacteria grown under control conditions. Furthermore, we showed that swimming and swarming motilities were hindered when bacteria were grown in the presence of the cranberry compounds. Because flagellum-mediated motility has been suggested to enable UPEC to disseminate to the upper urinary tract, we propose that inhibition of flagellum-mediated motility might be a key mechanism by which cPACs prevent UTIs. This is the first report to show that cranberry compounds inhibit UPEC motility via downregulation of the fliC gene. Further studies are required to establish whether these inhibitors play a role in vivo.

Iron chelation by cranberry juice and its impact on Escherichia coli growth.

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Authors
Lin B, Johnson BJ, Rubin RA, Malanoski AP, Ligler FS
Journal
Biofactors 37(2):121-30.
Abstract

The various health benefits of Vaccinium macrocarpon (cranberry) are well documented and have been attributed mainly to its antioxidant capacity and anti-adhesive activity. Several different mechanisms have been proposed to explain the possible role of cranberries, cranberry juice, and cranberry extracts in inhibiting bacterial growth. These mechanisms of action (i.e., inhibition of the microbial growth) have not been thoroughly studied. Here, we took advantage of current advances in microarray technology and used GeneChip® Escherichia coli genome 2.0 arrays to gain insight into the molecular mechanisms involved in the impact of cranberry juice on the properties of E. coli growth. The inclusion of cranberry juice in bacterial growth media was found to significantly impact the doubling time of E. coli. The gene expression results revealed altered expression of genes associated with iron transport and essential metabolic enzymes as well as with adenosine triphosphate (ATP) synthesis and fumarate hydratase in these cultures. The altered expression of genes associated with iron transport was consistent with the strong iron chelating capability of proanthocyanidins, a major constituent of cranberry juice. The iron depletion effect was confirmed by adding exogenous iron to the growth media. This addition partially reversed the inhibitory effect on bacterial growth observed in the presence of cranberry juice/extracts.

A-type cranberry proanthocyanidins inhibit the RANKL-dependent differentiation and function of human osteoclasts.

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Authors
Tanabe S, Santos J, La VD, Howell AB, Grenier D
Journal
Molecules. 16(3):2365-74
Abstract

This study investigated the effect of A-type cranberry proanthocyanidins (AC-PACs) on osteoclast formation and bone resorption activity. The differentiation of human pre-osteoclastic cells was assessed by tartrate-resistant acid phosphatase (TRAP) staining, while the secretion of interleukin-8 (IL-8) and matrix metalloproteinases (MMPs) was measured by ELISA. Bone resorption activity was investigated by using a human bone plate coupled with an immunoassay that detected the release of collagen helical peptides. AC-PACs up to 100 microg/mL were atoxic for osteoclastic cells. TRAP staining evidenced a dose-dependent inhibition of osteoclastogenesis. More specifically, AC-PACs at 50 microg/mL caused a 95% inhibition of RANKL-dependent osteoclast differentiation. This concentration of AC-PACs also significantly increased the secretion of IL-8 (6-fold) and inhibited the secretion of both MMP-2 and MMP-9. Lastly, AC-PACs (10, 25, 50 and 100 microg/ml) affected bone degradation mediated by mature osteoclasts by significantly decreasing the release of collagen helical peptides. This study suggests that AC-PACs can interfere with osteoclastic cell maturation and physiology as well as prevent bone resorption. These compounds may be considered as therapeutic agents for the prevention and treatment of periodontitis.