PURPOSE: The aim of this narrative literature review was to summarize evidence regarding bacteriuria and urinary tract infections (UTIs) in patients living with a urinary diversion and the use of cranberry products for the prevention of these infections. 

METHODS: We searched for articles in the English language and available in full text to address the role of cranberry products in the management of UTIs in those with urinary diversions. We searched the electronic databases of MEDLINE, PubMed, and the Cochrane Central Register of Controlled Trials between January 2003 and December 2023. Thirty-two elements were read in full and 9 elements that evaluated UTIs and/or the role of cranberries in preventing UTIs are included in this narrative review. 

RESULTS: Research indicates no significant difference in UTI rates, microbiology, or antibiotic sensitivity and resistance patterns between the different types of urinary diversions (orthoptic diversions, ileal conduit diversions, and continent cutaneous diversions). Similar to persons with an intact urinary tract, Escherichia coli (a prevalent coliform bacteria) was the most prevalent pathogen resulting in symptomatic UTIs. In addition, we found that E. coli strains persisted in urinary diversions involving reconstructed intestinal segments for prolonged periods of time despite antibiotic treatment. We found sparse evidence suggesting that cranberry products are effective for the prevention of UTIs after ileal conduit urinary diversion. 

CONCLUSIONS: There are inconsistencies in the definition of bacteriuria in the literature making it difficult to compare findings among the studies. Clinical guidance discussing the optimal method for obtaining a urine specimen from a urinary diversion and its management is limited. Research studies on the use of cranberry products to treat UTIs in persons living with a urinary diversion are urgently needed.

Cranberry supplements are commonly used to prevent urinary tract infections (UTIs). However, their usefulness is uncertain in pregnant women. We aimed to comprehensively summarize the current knowledge on cranberry supplements' efficacy and acceptability during pregnancy in addition to the outcome's measurement methods and studies' feasibility. To achieve it, we searched PubMed, PMC, and Europe PMC databases plus screened citations followed by critical appraisal of included eligible English written primary studies that (1) focused on pregnant women supplemented with any cranberry supplements; (2) provided data on cranberry supplements' efficacy, acceptability, outcomes measurement methods, and studies' feasibility; (3) included human subjects; and (4) published worldwide. Two randomized clinical trials (RCTs) and one nested cohort study, including 1156 pregnant women in total, contributed to our analysis. A tendency toward UTI reduction was demonstrated, although the results' validity was impacted by significant juice-induced gastrointestinal intolerance (23%; 44 of 188 subjects). Changing the form of supplementation from cranberry juice to capsules reduced the issue, causing side effects in one of 49 subjects (2%). Nevertheless, both RCTs still experienced significant recruitment and retention problems, which were at 33% and 59% on average, respectively. Newly acquired safety data on 919 more subjects suggests no increased risks of all malformations, vaginal bleeding, and neonatal complications. Investigating cranberry capsules' efficacy as a non-antibacterial option for UTI prevention in pregnant women has become a feasible and important direction with the current advancement in understanding cranberry supplements' actions, recommended doses plus regimens, and their safety in the population. We reviewed the challenges and discovered knowledge gaps and the implementation strategies for future studies.

BACKGROUND: Cranberries contain proanthocyanidins (PACs), which inhibit the adherence of p-fimbriated Escherichia coli to the urothelial cells lining the bladder. Cranberry products have been used widely for several decades to prevent urinary tract infections (UTIs). This is the fifth update of a review first published in 1998 and updated in 2003, 2004, 2008, and 2012.OBJECTIVES: To assess the effectiveness of cranberry products in preventing UTIs in susceptible populations.

SEARCH METHODS: We searched the Cochrane Kidney and Transplant Specialised Register up to 13 March 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA: All randomised controlled trials (RCTs) or quasi-RCTs of cranberry products compared with placebo, no specific treatment or other intervention (antibiotics, probiotics) for the prevention of UTIs were included.

DATA COLLECTION AND ANALYSIS: At least two authors independently assessed and extracted data. Information was collected on methods, participants, interventions and outcomes (incidence of symptomatic UTIs, positive culture results, side effects, adherence to therapy). Risk ratios (RR) with 95% confidence intervals (CI) were calculated where appropriate. Study quality was assessed using the Cochrane risk of bias assessment tool. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS: For this update, 26 new studies were added, bringing the total number of included studies to 50 (8857 randomised participants). The risk of bias for sequence generation and allocation concealment was low for 29 and 28 studies, respectively. Thirty-six studies were at low risk of performance bias, and 23 studies were at low risk of detection bias. Twenty-seven, 41, and 17 studies were at low risk of attrition bias, reporting bias and other bias, respectively. Forty-five studies compared cranberry products with placebo, water or no specific treatment in six different groups of participants. Twenty-six of these 45 studies could be meta-analysed for the outcome of symptomatic, culture-verified UTIs. In moderate certainty evidence, cranberry products reduced the risk of UTIs (6211 participants: RR 0.70, 95% CI 0.58 to 0.84; I = 69%). When studies were divided into groups according to the treatment indication, cranberry products probably reduced the risk of symptomatic, culture-verified UTIs in women with recurrent UTIs (8 studies, 1555 participants: RR 0.74, 95% CI 0.55 to 0.99; I = 54%), in children (5 studies, 504 participants: RR 0.46, 95% CI 0.32 to 0.68; I = 21%) and in people with a susceptibility to UTIs due to an intervention (6 studies, 1434 participants: RR 0.47, 95% CI 0.37 to 0.61; I = 0%). However, there may be little or no benefit in elderly institutionalised men and women (3 studies, 1489 participants: RR 0.93, 95% CI 0.67 to 1.30; I = 9%; moderate certainty evidence), pregnant women (3 studies, 765 participants: RR 1.06, 95% CI 0.75 to 1.50; I = 3%; moderate certainty evidence), or adults with neuromuscular bladder dysfunction with incomplete bladder emptying (3 studies, 464 participants: RR 0.97, 95% CI 0.78 to 1.19; I = 0%; low certainty evidence). Other comparisons were cranberry products with probiotics (three studies) or antibiotics (six studies), cranberry tablets with cranberry liquid (one study), and different doses of PACs (two studies). Compared to antibiotics, cranberry products may make little or no difference to the risk of symptomatic, culture-verified UTIs (2 studies, 385 participants: RR 1.03, 95% CI 0.80 to 1.33; I = 0%) or the risk of clinical symptoms without culture (2 studies, 336 participants: RR 1.30, 95% CI 0.79 to 2.14; I = 68%). Compared to probiotics, cranberry products may reduce the risk of symptomatic, culture-verified UTIs (3 studies, 215 participants: RR 0.39, 95% CI 0.27 to 0.56; I = 0%). It is unclear whether efficacy differs between cranberry juice and tablets or between different doses of PACs, as the certainty of the evidence was very low. The number of participants with gastrointestinal side effects probably does not differ between those taking cranberry products and those receiving a placebo or no specific treatment (10 studies, 2166 participants: RR 1.33, 95% CI 1.00 to 1.77; I = 0%; moderate certainty evidence). There was no clear relationship between compliance with therapy and the risk for repeat UTIs. No difference in the risk for UTIs could be demonstrated between low, moderate and high doses of PACs.

AUTHORS' CONCLUSIONS: This update adds a further 26 studies, taking the total number of studies to 50 with 8857 participants. These data support the use of cranberry products to reduce the risk of symptomatic, culture-verified UTIs in women with recurrent UTIs, in children, and in people susceptible to UTIs following interventions. The evidence currently available does not support its use in the elderly, patients with bladder emptying problems, or pregnant women.

Background: Cranberries (particularly in the form of cranberry juice) have been used widely for several decades for the prevention and treatment of urinary tract infections (UTIs). The aim of this review is to assess the effectiveness of cranberries in treating such infections.

Objectives: To assess the effectiveness of cranberries for the treatment of UTIs.

Search methods: We searched the Cochrane Kidney and Transplant Register of Studies up to 1 August 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Portal (ICTRP) Search Portal and ClinicalTrials.gov.

Selection criteria: All randomised controlled trials (RCTs) or quasi-RCTs of cranberry juice or cranberry products for the treatment of UTIs. Studies of men, women or children were to be included.Data collection and analysisTitles and abstracts of studies that were potentially relevant to the review were screened and studies that were clearly ineligible were discarded. Further information was sought from the authors where papers contained insufficient information to make a decision about eligibility.Main resultsNo studies were found that fulfilled all of our inclusion criteria. Seven studies were excluded because they were the wrong study design, mixed interventions or did not report any relevant outcomes. One study is ongoing; however, its current status is unknown.

Authors' conclusions: After a thorough search, no RCTs which assessed the effectiveness of cranberry juice for the treatment of UTIs were found. Therefore, at the present time, there is no good quality evidence to suggest that it is effective for the treatment of UTIs. Well-designed parallel-group, double-blind studies comparing cranberry juice and other cranberry products versus placebo to assess the effectiveness of cranberry juice in treating UTIs are needed. Outcomes should include a reduction in symptoms, sterilisation of the urine, side effects and adherence to therapy. The dosage (amount and concentration) and duration of therapy should also be assessed. Consumers and clinicians will welcome the evidence from these studies.

PLAIN LANGUAGE SUMMARY: Still waiting for evidence about whether cranberries are useful for treating urinary tract infectionsCranberries contain a substance that can prevent bacteria from sticking to the walls of the bladder. This may help reduce bladder and other urinary tract infections (UTIs). Cranberries (usually as cranberry juice) have been used to try and treat UTIs, particularly in high-risk groups such as older people. Cranberries have few adverse effects. This review found no studies reporting the effects of cranberry juice or other cranberry products on the treatment of UTIs.

BACKGROUND AND OBJECTIVE: With over 50% of women suffering from at least one episode of urinary tract infection (UTI) each year and an increasing prevalence of antimicrobial resistance, efforts need to be made to clearly identify the evidence supporting potential non-drug interventions. This study aims to compare the effects of cranberry juice, cranberry tablets, and increased liquids for the management of UTIs.

METHODS: PubMed, Embase, and Cochrane CENTRAL were searched for randomised controlled trials. The primary outcome was the number of UTIs, and the secondary outcomes were UTI symptoms and antimicrobial consumption. A risk of bias assessment was performed using the Cochrane risk of bias tool, and the certainty of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation.

KEY FINDINGS AND LIMITATIONS: A total of 20 trials (3091 participants) were included, with 18 studies highlighting a 54% lower rate of UTIs with cranberry juice consumption than no treatment and a 27% lower rate than placebo liquid. Cranberry juice also resulted in a 49% lower rate of antibiotic use than placebo liquid and a 59% lower rate than no treatment, based on a network meta-analysis of six studies. The use of cranberry compounds also reduced the prevalence of symptoms associated with UTIs.

CONCLUSIONS AND CLINICAL IMPLICATIONS: With moderate to low certainty, the evidence supports the use of cranberry juice for the prevention of UTIs. While increased liquids reduce the rate of UTIs compared with no treatment, cranberry in liquid form provides even better clinical outcomes in terms of reduction in UTIs and antibiotic use and should be considered for the management of UTIs.

PATIENT SUMMARY: With the increasing prevalence of antimicrobial-resistant UTIs, alternate non-drug treatment options for its management are required. Available evidence supports the use of cranberry compounds and increases in fluid intake for managing UTIs.

Urinary tract infections (UTIs) are the most frequent bacterial infections in the clinical setting. Even without underlying anatomic or functional abnormalities, more than 40% of women experience at least one UTI in their lifetime, of which 30% develop recurrent UTIs (rUTIs) within 6 months. Conventional management with antibiotics for rUTIs may eventually lead to the development of multidrug-resistant uropathogens. Targeting of the pathogenicity of rUTIs, the evolution of uropathogenic Escherichia coli (UPEC), and inadequate host defenses by immune responses should be explored to provide non-antibiotic solutions for the management of rUTIs. The adaptive evolution of UPEC has been observed in several aspects, including colonization, attachment, invasion, and intracellular replication to invade the urothelium and survive intracellularly. Focusing on the antivirulence of UPEC and modulating the immunity of susceptible persons, researchers have provided potential alternative solutions in four categories: antiadhesive treatments (i.e., cranberries and D-mannose), immunomodulation therapies, vaccines, and prophylaxis with topical estrogen therapy and probiotics (e.g., Lactobacillus species). Combination therapies targeting multiple pathogenic mechanisms are expected to be a future trend in UTI management, although some of these treatment options have not been well established in terms of their long-term efficacy. Additional clinical trials are warranted to validate the therapeutic efficacy and durability of these techniques.

Purpose of review: There is a growing interest in nonantibiotic prevention strategies for recurrent urinary tract infections (rUTIs). Our objective is to provide a focused, pragmatic review of the latest evidence.

Recent findings: Vaginal estrogen is well tolerated and effective for preventing rUTI in postmenopausal women. Cranberry supplements at sufficient doses are effective in preventing uncomplicated rUTI. Methenamine, d-mannose, and increased hydration all have evidence to support their use, although the evidence is of somewhat variable quality.There is sufficient evidence to recommend vaginal estrogen and cranberry as first-line rUTI prevention strategies, particularly in postmenopausal women. Prevention strategies can be used in series or in tandem, based on patient preference and tolerance for side effects, to create effective nonantibiotic rUTI prevention strategies.

Background: Urinary tract infection has a one-year prevalence of 11% in women and ranges among the most common reasons for consulting a primary care physician and for receiving a prescription for antibiotics. In the case of recurrent urinary tract infection (rUTI), there are questions about the further work-up, treatment, and preventive measures. 

Methods: The systematic literature search performed for the update of the German clinical practice guideline on uncomplicated urinary tract infection (043-044) (up to February 2022) was supplemented with a selective search for clinical trials (up to August 2023). 

Results: Urine culture and ultrasonography are reasonable steps in the diagnostic evaluation of rUTI. Further invasive testing is suggested for men but is not routinely indicated for women. Antibiotics are among the most effective preventive measures (risk ratio [RR] 0.15, 95% confidence interval [0.1; 0.3]) but carry a high risk of side effects. Non-antibiotic preparations such as cranberry juice (RR 0.74 [0.5; 0.99]), mannose (RR 0.23 [0.14; 0.37]), and vaginal estrogen (RR, 0.42 [0.30; 0.59]) can also reduce the infection rate, with a low risk of side effects. Increased daily fluid intake has been shown to lower infection rates in the short term (odds ratio [OR] 0.13 [0.07; 0.25]); the use of hygienically advisable wiping techniques after passing stool or urine has been little studied but can be implemented with no risk. 

Conclusion: rUTI poses a challenge for the treating physician. The measures to be taken must be considered on an individual basis. Vulnerable groups, such as older patients, need special attention.

The treatment of infectious diseases typically includes the administration of anti-infectives; however, the increasing rates of antimicrobial resistance (AMR) have led to attempts to develop other modalities, such as antimicrobial peptides, nanotechnology, bacteriophages, and natural products. Natural products offer a viable alternative due to their potential affordability, ease of access, and diverse biological activities. Flavonoids, a class of natural polyphenols, demonstrate broad anti-infective properties against viruses, bacteria, fungi, and parasites. Their mechanisms of action include disruption of microbial membranes, inhibition of nucleic acid synthesis, and interference with bacterial enzymes. This review explores the potential of natural compounds, such as flavonoids, as an alternative therapeutic approach to combat infectious diseases. Moreover, it discusses some commonly used natural products, such as cranberry and D-mannose, to manage urinary tract infections (UTIs). Cranberry products and D-mannose both, yet differently, inhibit the adhesion of uropathogenic bacteria to the urothelium, thus reducing the likelihood of UTI occurrence. Some studies, with methodological limitations and small patient samples, provide some encouraging results suggesting the use of these substances in the prevention of recurrent UTIs. While further research is needed to determine optimal dosages, bioavailability, and potential side effects, natural compounds hold promise as a complementary or alternative therapeutic strategy in the fight against infectious diseases.

Background: Cranberries contain proanthocyanidins (PACs), which inhibit the adherence of p-fimbriated Escherichia coli to the urothelial cells lining the bladder. Cranberry products have been used widely for several decades to prevent urinary tract infections (UTIs). This is the fifth update of a review first published in 1998 and updated in 2003, 2004, 2008, and 2012. 

Objectives: To assess the effectiveness of cranberry products in preventing UTIs in susceptible populations. 

Search methods: We searched the Cochrane Kidney and Transplant Specialised Register up to 13 March 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register Search Portal (ICTRP) and ClinicalTrials.gov. 

Selection criteria: All randomised controlled trials (RCTs) or quasi-RCTs of cranberry products compared with placebo, no specific treatment or other intervention (antibiotics, probiotics) for the prevention of UTIs were included. 

Data collection and analysis: Two authors independently assessed and extracted data. Information was collected on methods, participants, interventions and outcomes (incidence of symptomatic UTIs, positive culture results, side effects, adherence to therapy). Risk ratios (RR) with 95% confidence intervals (CI) were calculated where appropriate. Study quality was assessed using the Cochrane risk of bias assessment tool. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. 

Main results: For this update 26 new studies were added, bringing the total number of included studies to 50 (8857 randomised participants). The risk of bias for sequence generation and allocation concealment was low for 29 and 28 studies, respectively. Thirty-six studies were at low risk of performance bias, and 23 studies were at low risk of detection bias. Twenty-seven, 41, and 17 studies were at low risk of attrition bias, reporting bias and other bias, respectively. Forty-five studies compared cranberry products with placebo or no specific treatment in six different groups of participants. Twenty-six of these 45 studies could be meta-analysed for the outcome of symptomatic, culture-verified UTIs. In moderate certainty evidence, cranberry products reduced the risk of UTIs (6211 participants: RR 0.70, 95% CI 0.58 to 0.84; I² = 69%). When studies were divided into groups according to the treatment indication, cranberry products probably reduced the risk of symptomatic, culture-verified UTIs in women with recurrent UTIs (8 studies, 1555 participants: RR 0.74, 95% CI 0.55 to 0.99; I² = 54%), in children (5 studies, 504 participants: RR 0.46, 95% CI 0.32 to 0.68; I² = 21%) and in people with a susceptibility to UTIs due to an intervention (6 studies, 1434 participants: RR 0.47, 95% CI 0.37 to 0.61; I² = 0%). However, in low certainty evidence, there may be little or no benefit in elderly institutionalised men and women (3 studies, 1489 participants: RR 0.93, 95% CI 0.67 to 1.30; I² = 9%), pregnant women (3 studies, 765 participants: RR 1.06, 95% CI 0.75 to 1.50; I² = 3%), or adults with neuromuscular bladder dysfunction with incomplete bladder emptying (3 studies, 464 participants: RR 0.97, 95% CI 0.78 to 1.19; I² = 0%). Other comparisons were cranberry products with probiotics (three studies) or antibiotics (six studies), cranberry tablets with cranberry liquid (one study), and different doses of PACs (two studies). Compared to antibiotics, cranberry products may make little or no difference to the risk of symptomatic, culture-verified UTIs (2 studies, 385 participants: RR 1.03, 95% CI 0.80 to 1.33; I² = 0%) or the risk of clinical symptoms without culture (2 studies, 336 participants: RR 1.30, 95% CI 0.79 to 2.14; I² = 68%). Compared to probiotics, cranberry products may reduce the risk of symptomatic, culture-verified UTIs (3 studies, 215 participants: RR 0.39, 95% CI 0.27 to 0.56; I = 0%). It is unclear whether efficacy differs between cranberry juice and tablets or between different doses of PACs as the certainty of the evidence was very low. The number of participants with gastrointestinal side effects probably does not differ between those taking cranberry products and those receiving placebo or no specific treatment (10 studies, 2166 participants: RR 1.33, 95% CI 1.00 to 1.77; I² = 0%; moderate certainty evidence). There was no clear relationship between compliance with therapy and the risk for repeat UTIs. No difference in the risk for UTIs could be demonstrated between low, moderate and high doses of PACs. 

Authors' conclusions: This update adds a further 26 studies taking the total number of studies to 50 with 8857 participants. These data support the use of cranberry products to reduce the risk of symptomatic, culture-verified UTIs in women with recurrent UTIs, in children, and in people susceptible to UTIs following interventions. The evidence currently available does not support its use in the elderly, patients with bladder emptying problems, or pregnant women.