Cranberry and Urinary Tract Infections

Abstract

Urinary tract infection (UTI) refers to the presence of clinical signs and symptoms arising from the genitourinary tract plus the presence of one or more micro-organisms in the urine exceeding a threshold value for significance (ranges from 102 to 103 colony-forming units/mL). Infections are localized to the bladder (cystitis), renal parenchyma (pyelonephritis) or prostate (acute or chronic bacterial prostatitis). Single UTI episodes are very common, especially in adult women where there is a 50-fold predominance compared with adult men. In addition, recurrent UTIs are also common, occurring in up to one-third of women after first-episode UTIs. Recurrences requiring intervention are usually defined as two or more episodes over 6 months or three or more episodes over 1 year (this definition applies only to young women with acute uncomplicated UTIs). A cornerstone of prevention of UTI recurrence has been the use of low-dose once-daily or post-coital antimicrobials; however, much interest has surrounded non-antimicrobial-based approaches undergoing investigation such as use of probiotics, vaccines, oligosaccharide inhibitors of bacterial adherence and colonization, and bacterial interference with immunoreactive extracts of Escherichia coli. Local (intravaginal) estrogen therapy has had mixed results to date. Cranberry products in a variety of formulations have also undergone extensive evaluation over several decades in the management of UTIs. At present, there is no evidence that cranberry can be used to treat UTIs. Hence, the focus has been on its use as a preventative strategy. Cranberry has been effective in vitro and in vivo in animals for the prevention of UTI. Cranberry appears to work by inhibiting the adhesion of type I and P-fimbriated uropathogens (e.g. uropathogenic E. coli) to the uroepithelium, thus impairing colonization and subsequent infection. The isolation of the component(s) of cranberry with this activity has been a daunting task, considering the hundreds of compounds found in the fruit and its juice derivatives. Reasonable evidence suggests that the anthocyanidin/proanthocyanidin moieties are potent antiadhesion compounds. However, problems still exist with standardization of cranberry products, which makes it extremely difficult to compare products or extrapolate results. Unfortunately, most clinical trials have had design deficiencies and none have evaluated specific key cranberry-derived compounds considered likely to be active moieties (e.g. proanthocyanidins). In general, the preventive efficacy of cranberry has been variable and modest at best. Meta-analyses have established that recurrence rates over 1 year are reduced approximately 35% in young to middle-aged women. The efficacy of cranberry in other groups (i.e. elderly, paediatric patients, those with neurogenic bladder, those with chronic indwelling urinary catheters) is questionable. Withdrawal rates have been quite high (up to 55%), suggesting that these products may not be acceptable over long periods. Adverse events include gastro...

Natural Approaches for Controlling Urinary Tract Infections

“…Currently, there is no evidence that cranberry can be used to treat UTIs. Hence, the focus has been on its use as a prophylactic agent in the prevention of UTIs (Guay, 2009). The consumption of cranberry juice can help to prevent the adhesion of UPEC to the uroepithelium and thereby help reduce the incidence of UTIs.…”

Morphometric abnormalities in spleen and kidney of the progeny of mice fed American cranberry extract (Vaccinium macrocarpon) during pregnancy and lactation

“…In order to avoid the use of antibiotics, cranberries and their extracts, which exhibit anti-bacterial properties, are now often recommended as an alternative therapy. Dietary supplements containing cranberries are also used in veterinary medicine in urinary tract infections in dogs and cats (Guay 2009). It was reported that the A-type procyanidin isolated from cranberry juice exhibited an anti-adhesive effect against E. coli binding to urinary tract epithelial cells.…”

“…It was reported that the A-type procyanidin isolated from cranberry juice exhibited an anti-adhesive effect against E. coli binding to urinary tract epithelial cells. However, there is no sufficient clinical evidence that cranberry type-A proanthocyanidins are effective at lowering the risk of urinary tract infection (Guay 2009, Jepson et al 2012, Vasileiou et al 2013. Some authors did not show the effectiveness of cranberry used versus placebo (McMurdo et al 2005).…”

Comparison of A-type Proanthocyanidins in Cranberry and Peanut Skin Extracts Using Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

“…The American red cranberry (Vaccinium macrocarpon) has been recognized for its benefits to the urinary tract [3]. Consumption of cranberry juice helps prevent UTIs [5]. A few theories regarding the mechanism have been proposed.…”