Synthetic multimeric heptyl mannosides as potent antiadhesives of uropathogenic Escherichia coli.
Urinary tract infections caused by uropathogenic Escherichia coli presents a serious communal and nosocomial health problem initiated by bacterial adhesion to the bladder cells. E. coli expresses fimbriae with a mannose-binding adhesin, FimH, at the tip. Heptyl alpha-D-mannoside (HM) is a nanomolar inhibitor of this lectin, preventing adhesion of type 1-piliated E. coli and reducing bacteria levels in a murine cystitis model. Herein, we described the synthesis of multimeric heptyl-mannosides with valencies ranging from one to four by copper-catalyzed azide alkyne cycloaddition (CuAAC). Biological evaluation of the multivalent compounds revealed an increase in potency compared to HM. Inhibition of bladder cell binding highlighted a promising tetravalent derivative with inhibitory concentrations 6000- and 64-fold lower than mannose and HM respectively.
ChemMedChem. 2009 May;4(5):749-55
Antiadhesion therapy for urinary tract infections—a balanced PK/PD profile proved to be key for success.
The initial step for the successful establishment of urinary tract infections (UTIs), predominantly caused by uropathogenic Escherichia coli, is the adhesion of bacteria to urothelial cells. This attachment is mediated by FimH, a mannose-binding adhesin, which is expressed on the bacterial surface. To date, UTIs are mainly treated with antibiotics, leading to the ubiquitous problem of increasing resistance against most of the currently available antimicrobials. Therefore, new treatment strategies are urgently needed, avoiding selection pressure and thereby implying a reduced risk of resistance. Here, we present a new class of highly active antimicrobials, targeting the virulence factor FimH. When the most potent representative, an indolinylphenyl mannoside, was administered in a mouse model at the low dosage of 1 mg/kg (corresponding to approximately 25 µg/mouse), the minimal therapeutic concentration to prevent UTI was maintained for more than 8 h. In a treatment study, the colony-forming units in the bladder could be reduced by almost 4 orders of magnitude, comparable to the standard antibiotic treatment with ciprofloxacin (8 mg/kg, sc).
J Med Chem. 2012 May 24;55(10):4700-13
In-vitro and in-vivo evidence of dose-dependent decrease of uropathogenic Escherichia coli virulence after consumption of commercial Vaccinium macrocarpon (cranberry) capsules.
This study evaluated the antibacterial efficacy of the consumption of cranberry capsules vs. placebo in the urine of healthy volunteers. A first double-blind, randomised, crossover trial involved eight volunteers who had followed three regimens, with or without cranberry, with a wash-out period of at least 6 days between each regimen. Twelve hours after consumption of cranberry or placebo hard capsules, the first urine of the morning was collected. Different Escherichia coli strains were cultured in the urine samples. Urinary antibacterial adhesion activity was measured in vitro using the human T24 epithelial cell-line, and in vivo using the Caenorhabditis elegans killing model. With the in-vitro model, 108 mg of cranberry induced a significant reduction in bacterial adherence to T24 cells as compared with placebo (p <0.001). A significant dose-dependent decrease in bacterial adherence in vitro was noted after the consumption of 108 and 36 mg of cranberry (p <0.001). The in-vivo model confirmed that E. coli strains had a reduced ability to kill C. elegans after growth in the urine of patients who consumed cranberry capsules. Overall, these in-vivo and in-vitro studies suggested that consumption of cranberry juice represents an interesting new strategy to prevent recurrent urinary tract infection.
Clin Microbiol Infect. 2008 Apr;14(4):350-5
Effect of cranberry drink on bacterial adhesion in vitro and vaginal microbiota in healthy females.
INTRODUCTION/OBJECTIVE: Cranberries have been shown to produce urinary metabolites that influence uropathogen adhesion and prevent urinary tract infections. This study was designed to determine if consuming reconstituted, unsweetened cranberry drink from extract retained its bioactive properties by reducing uropathogen adhesion without adversely affecting urinary calcium, magnesium and the vaginal microflora. MATERIALS AND METHODS: A randomized crossover study was undertaken in 12 healthy women consuming reconstituted unsweetened cranberry drink, CranActin or water. The urine was collected at 4 hours and 1 week of consumption and evaluated for antiadhesive properties and urinary pH, calcium and magnesium. Vaginal swabs were collected after 1 week of treatment to assess the vaginal microbiota by DGGE. RESULTS: The resultant urine produced by subjects who consumed 500 ml reconstituted cranberry extract twice per day, significantly reduced the adherence to epithelial cells of P-fimbriated uropathogenic Escherichia coli and showed a tendency towards significance for two E. coli strains expressing fimbriae and an Enterococcus faecalis isolate. The cranberry drink treatment did not alter urinary pH, but reduced calcium and magnesium concentrations compared to water, although not to statistical significance. The reconstituted cranberry drink had no apparent detrimental effect on the vaginal microbiota. However, consuming twice daily resulted in an apparent loss of a potential pathogen from the vagina in 42% subjects. CONCLUSIONS: The present findings suggest that reconstituted cranberry drink may retain the ability to reduce the risk of UTI by inhibiting pathogen adhesion while not detrimentally affecting urinary pH or vaginal microbiota, or the risk of calculi.
Can J Urol. 2 009 Dec;16(6):4901-7
Dosage effect on uropathogenic Escherichia coli anti-adhesion activity in urine following consumption of cranberry powder standardized for proanthocyanidin content: a multicentric randomized double blind study.
BACKGROUND: Ingestion of cranberry (Vaccinium macrocarpon Ait.) has traditionally been utilized for prevention of urinary tract infections. The proanthocyanidins (PACs) in cranberry, in particular the A-type linkages have been implicated as important inhibitors of primarily P-fimbriated E. coli adhesion to uroepithelial cells. Additional experiments were required to investigate the persistence in urine samples over a broader time period, to determine the most effective dose per day and to determine if the urinary anti-adhesion effect following cranberry is detected within volunteers of different origins. METHODS: Two separate bioassays (a mannose-resistant hemagglutination assay and an original new human T24 epithelial cell-line assay) have assessed the ex-vivo urinary bacterial anti-adhesion activity on urines samples collected from 32 volunteers from Japan, Hungary, Spain and France in a randomized, double-blind versus placebo study. An in vivo Caenorhabditis elegans model was used to evaluate the influence of cranberry regimen on the virulence of E. coli strain. RESULTS: The results indicated a significant bacterial anti-adhesion activity in urine samples collected from volunteers that consumed cranberry powder compared to placebo (p < 0.001). This inhibition was clearly dose-dependent, prolonged (until 24 h with 72 mg of PAC) and increasing with the amount of PAC equivalents consumed in each cranberry powder regimen. An in vivo Caenorhabditis elegans model showed that cranberry acted against bacterial virulence: E. coli strain presented a reduced ability to kill worms after a growth in urines samples of patients who took cranberry capsules. This effect is particularly important with the regimen of 72 mg of PAC. CONCLUSIONS: Administration of PAC-standardized cranberry powder at dosages containing 72 mg of PAC per day may offer some protection against bacterial adhesion and virulence in the urinary tract. This effect may offer a nyctohemeral protection.
BMC Infect Dis. 2010 Apr 14;10:94
Inhibitory activity of cranberry extract on the bacterial adhesiveness in the urine of women: an ex-vivo study.
Strains of uropathogenic E. coli are responsible for approximately 90% of community-acquired, uncomplicated cystitis, and fimbriae represent the adhesive factors enabling E. coli to be anchored to uroepithelial cells in the first step of the infectious process. Recently, a few studies have shown that a correlation between the consumption of cranberry (Vaccinium macrocarpon) and prevention of UTI is related to the ability of proanthocyanidins to reduce the bacterial adhesion to uroepithelial cells. In this study we evaluate the inhibitory activity of urine of healthy women treated with tablets containing cranberry extract on the adhesiveness of E. coli to uroepithelial human cells. Two groups of 12 female volunteers each, aged between 18 and 65 years, were enrolled, one group with negative history and one group with positive history of recurrent cystitis. Subjects were treated with the active product or placebo in a random, cross-over, double-blinded sequence for one week in each of the two treatment sequences. Urine samples were collected at the beginning and the end of each study period. Tests of bacterial adhesiveness were performed with two strains of E. coli (ATCC 25922 and ATCC 35218) on HT1376 human bladder carcinoma cells. Significant reductions of bacterial adhesiveness were observed in women who received cranberry extract (-50.9%; p less than 0.0001), regardless of their medical history and the treatment period in the cross-over sequence. No changes were observed with placebo (-0.29%; n.s.). This ex-vivo study showed that the assumption of cranberry extract in suitable amounts can have an anti-adhesive activity on uropathogenic E. coli.
Int J Immunopathol Pharmacol. 2010 Apr-Jun;23(2):611-8
Vaccinium macrocarpon: an interesting option for women with recurrent urinary tract infections and other health benefits.
AIM: To review the scientific publications concerning the clinical use and mechanism of action of the North American cranberry (Vaccinium macrocarpon) for women with recurrent urinary tract infections (UTI) and other health conditions. METHODS: This is a retrospective study of published information concerning Vaccinium macrocarpon retrieved from a PubMed and individual searches. RESULTS: Urinary tract infections are very common in women, cause discomfort, and may aggravate other genitourinary conditions. The available scientific information supports a clinical benefit of Vaccinium macrocarpon in the prevention of recurrent UTI in women. There is a non-significant reduction of UTI associated with Vaccinium macrocarpon treatment during pregnancy. A group of proanthocyanidins (PAC) with A-type linkages have been isolated from Vaccinium macrocarpon which inhibit P-fimbriae synthesis and induce a bacterial deformation, on both antibiotic-susceptible and antibiotic-resistant uropathogenic Escherichia coli. It is plausible that cranberry PAC prevent bacteria from adhering to the uroepithelium of the bladder, thereby blocking the ability of E. coli to infect the urinary mucosa. CONCLUSION: Cranberry treatment is a safe, well-tolerated supplement that does not have significant drug interactions. Although investigations are in the early stages, experimental and preclinical studies suggest that cranberry components may have other potential benefits, including anti-infective, anticancer and antioxidant effects, which may be considered as positive for different age-related conditions. In addition, cranberry components may induce positive cardiovascular and metabolic changes, and may improve neuropsychological activity. These effects warrant further clinical research to better place the role of cranberry products for women.
J Obstet Gynaecol Res. 2009 Aug;35(4):630-9
Oral consumption of cranberry juice cocktail inhibits molecular-scale adhesion of clinical uropathogenic Escherichia coli.
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.
J Med Food. 2011 Jul-Aug;14(7-8):739-45
Effects of Cranberry Extracts on Growth and Biofilm Production of Escherichia coli and Staphylococcus species.
Biofilm producing bacteria such as Staphylococcus species and Escherichia coli are the most common cause of catheter related urinary tract infections (UTIs). The American cranberry (Vaccinium macrocarpon) is utilized widely as a prophylaxis for UTIs due to its prevention of microbial adhesion. Cranberry contains proanthocyanidins (PACs), which have been implicated as active constituents responsible for its bacterial antiadhesive properties. Despite overwhelming data supporting cranberry’s beneficial effects against human pathogenic bacteria, there is limited information regarding its effects on biofilm formation. This study evaluated the effects of three proprietary PAC-standardized cranberry extracts on the inhibition of bacterial growth and biofilm production against a panel of clinically relevant pathogens: Staphylococcus epidermidis, Staphylococcus aureus, clinical methicillin-resistant S. aureus (MRSA), Staphylococcus saprophyticus and Escherichia coli. The extracts inhibited the growth of the Gram-positive bacteria (Staphylococcus spp.) but not the Gram-negative species (E. coli) with minimum inhibitory concentrations in the range 0.02-5 mg/mL. The extracts also inhibited biofilm production by the Gram-positive bacteria but did not eradicate their established biofilm. These results suggest that cranberry may have beneficial effects against the growth and biofilm producing capability of Gram-positive bacteria pathogens.
Phytother Res. 2012 Sep;26(9):1371-4
Effects of cranberry extracts and ursolic acid derivatives on P-fimbriated Escherichia coli, COX-2 activity, pro-inflammatory cytokine release and the NF-kappabeta transcriptional response in vitro.
Cranberry, the fresh or dried ripe fruit of Vaccinium macrocarpon Ait. (Ericaceae), is currently used as adjunct therapy for the prevention and symptomatic treatment of urinary tract infections. Data from clinical trials suggest that extracts of cranberry or cranberry juice reduce the bacterial load of E. coli and also suppress the inflammatory symptoms induced by E. coli infections. A methanol extract prepared from 10 kg of dehydrated cranberries did not directly inhibit the growth of E coli strains ATCC 700336 or ATCC 25922 in concentrations up to 256 mug/mL in vitro. However, the methanol extract (CR-ME) inhibited the activity of cyclooxygenase-2, with an IC(50) of 12.8 mug/mL. Moreover, CR-ME also inhibited the NF-kappabeta transcriptional activation in human T lymphocytes with an IC(50) of 19.4 mug/mL, and significantly (p < 0.01) inhibited the release of interleukin (IL)-1beta, IL-6, IL-8 and tumor necrosis factor-alpha from E. coli lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells in vitro, at a concentration of 50 mug/mL. The extract had no effect on inducible nitric oxide synthase activity in the murine macrophage cell line RAW 264.7. The compounds responsible for this activity were identified using a novel LC-MS based assay as ursolic acid and ursolic acid derivatives. Taken together, these data suggest CR-ME and its constituent chemical compounds target specific pathways involved in E. coli-induced inflammation.