Host factors in susceptibility to urinary tract infections

D-MannosE to prevent Recurrent urinary tract InfecTions (MERIT): protocol for a randomised controlled trial

INTRODUCTION

Recurrent urinary tract infections (RUTIs) have a significant negative impact on quality of life and healthcare costs. To date, daily prophylactic antibiotics are the only treatment which have been shown to help prevent RUTIs. D-mannose is a type of sugar which is believed to inhibit bacterial adherence to uroepithelial cells, and is already being used by some women in an attempt to prevent RUTIs. There is currently insufficient rigorous evidence on which to base decisions about its use. The D-mannose to prevent recurrent urinary tract infections (MERIT) study will evaluate whether D-mannose is clinically and cost-effective in reducing frequency of infection and symptom burden for women presenting to UK primary care with RUTI.

METHODS AND ANALYSIS

MERIT will be a two-arm, individually randomised, double blind placebo controlled, pragmatic trial. Participants will be randomised to take D-mannose powder or placebo powder daily for 6 months. The primary outcome will be the number of medical attendances attributable to symptoms of RUTI. With 508 participants we will have 90% power to detect a 50% reduction in the chance of a further clinically suspected UTI, assuming 20% lost to follow-up. Secondary outcomes will include: number of days of moderately bad symptoms of UTI; time to next consultation; number of clinically suspected UTIs; number of microbiologically proven UTIs; number of antibiotic courses for UTI; quality of life and healthcare utilisation related to UTI. A within trial economic evaluation will be conducted to examine cost-effectiveness of D-mannose in comparison with placebo. A nested qualitative study will explore participants' experiences and perceptions of recruitment to, and participation in a study requiring a daily treatment.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from South West-Central Bristol Research Ethics Committee. Publication of the MERIT study is anticipated to occur in 2021.

TRIAL REGISTRATION NUMBER

ISRCTN 13283516.

Standardised Chinese herbal treatment delivered by GPs compared with individualised treatment administered by practitioners of Chinese herbal medicine for women with recurrent urinary tract infections (RUTI): study protocol for a randomised controlled trial

BACKGROUND

In the UK, urinary tract infections (UTIs) are the most common bacterial infection presented by women in primary care. Recurrent urinary tract infections (RUTIs) are defined as three episodes of UTI in the last 12 months, or two episodes in the last 6 months. Between 20 and 30 % of women who have had one episode of UTI will have an RUTI, and approximately 25 % of these will develop subsequent recurrent episodes. RUTIs can have a significant negative effect on the quality of life, and have a high impact on health care costs as a result of outpatient visits, diagnostic tests and prescriptions. Chinese herbal medicine (CHM) has a recorded history of treatments for the symptoms of UTIs for more than 2000 years. More recent clinical research in China has provided some preliminary evidence that CHM can alleviate the symptoms of UTIs and reduce the rate of recurrence, but more rigorous investigation is required.

METHODS/DESIGN

The RUTI trial is a double-blind, randomised, placebo-controlled, feasibility trial. A total of 80 women will be randomised to 'individualised' herbs prescribed by a Chinese herbal practitioner or to 'standardised' herbs provided by primary care clinicians. Both arms will have herbs for prevention of UTIs and treatment of acute episodes. Treatment duration is for 16 weeks. The primary outcomes are the number of episodes of recurrent UTIs during the trial period and in the 6 months of follow-up, and the number of days of symptoms rated moderately bad or worse based on patient diaries. Secondary outcomes will assess participant expectations and beliefs, adherence to the treatment, adverse events and health economics and provide quantitative and qualitative assessments of the impact of recurrent infections on the lives of women.

DISCUSSION

The RUTI trial is the first instance of CHM delivered as a clinical trial of an investigatory medicinal product in the UK. This study provides important information regarding the feasibility and acceptability of researching and using CHM in Primary care. Once completed, it will provide provisional estimates of the variance of change in continuous outcomes to inform a power calculation for a larger, more definitive trial.

TRIAL REGISTRATION

EudraCT, 2013-004657-24 . Registered on 5 September 2014.

Chinese herbal medicine for treating recurrent urinary tract infections in women

BACKGROUND

Acute urinary tract infection (UTI) is a common bacterial infection that affects 40% to 50% of women. Between 20% and 30% of women who have had a UTI will experience a recurrence, and around 25% will develop ongoing recurrent episodes with implications for individual well-being and healthcare costs. Prophylactic antibiotics can prevent recurrent UTIs but there are growing concerns about microbial resistance, side effects from treatment and lack of long-term benefit. Consequently, alternative treatments are being investigated. Chinese herbal medicine (CHM) has a recorded history of treating UTI symptoms and more recent research suggests a potential role in the management of recurrent UTIs. This review aimed to evaluate CHM for recurrent UTI.

OBJECTIVES

This review assessed the benefits and harms of CHM for the treatment of recurrent UTIs in adult women, both as a stand-alone therapy and in conjunction with other pharmaceutical interventions.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant's Specialised Register to 7 May 2015 through contact with the Trials Search Co-ordinator, using search terms relevant to this review. We also searched AMED, CINAHL and the Chinese language electronic databases Chinese BioMedical Literature Database (CBM), China Network on Knowledge Infrastructure (CNKI), VIP and Wan Fang Databases to July 2014.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing treatments using CHM with either an inactive placebo or conventional biomedical treatment. RCTs comparing different CHM strategies and treatments were eligible for inclusion. Quasi-randomised studies were excluded.

DATA COLLECTION AND ANALYSIS

Data extraction was carried out independently by two authors. Where more than one publication of one study existed, these were grouped and the publication with the most complete data was used in the analyses. Where relevant outcomes were only published in earlier versions these data were used. All meta-analyses were performed using relative risk (RR) for dichotomous outcomes with 95% confidence intervals (CI).

MAIN RESULTS

We included seven RCTs that involved a total of 542 women; of these, five recruited post-menopausal women (aged from 56 to 70 years) (422 women). We assessed all studies to be at high risk of bias. Meta-analyses comparing the overall effectiveness of treatments during acute phases of infection and rates of recurrence were conducted. Analysis of three studies involving 282 women that looked at CHM versus antibiotics suggested that CHM had a higher rate of effectiveness for acute UTI (RR 1.21, 95% CI 1.11 to 33) and reduced recurrent UTI rates (RR 0.28, 95% CI 0.09 to 0.82). Analysis of two studies involving 120 women that compared CHM plus antibiotics versus antibiotics alone found the combined intervention had a higher rate of effectiveness for acute UTI (RR 1.24, 95% CI 1.04 to 1.47) and resulted in lower rates of recurrent infection six months after the study (RR 0.53, 95% CI 0.35 to 0.80).One study comparing different CHM treatments found Er Xian Tang was more effective in treating acute infection in post-menopausal women than San Jin Pian (80 women: RR 1.28, 95% CI 1.03 to 1.57). Analysis showed that active CHM treatments specifically formulated for recurrent UTI were more effective in reducing infection incidence than generic CHM treatments that were more commonly used for acute UTI (RR 0.40, 95% CI 0.21 to 0.77).Only two studies undertook to report adverse events; neither reported the occurrence of any adverse events.

AUTHORS' CONCLUSIONS

Evidence from seven small studies suggested that CHM as an independent intervention or in conjunction with antibiotics may be beneficial for treating recurrent UTIs during the acute phase of infection and may reduce the recurrent UTI incidence for at least six months post-treatment. CHM treatments specifically formulated for recurrent UTI may be more effective than herbal treatments designed to treat acute UTI. However, the small number and poor quality of the included studies meant that it was not possible to formulate robust conclusions on the use of CHM for recurrent UTI in women either alone or as an adjunct to antibiotics.

The challenges of treating women with recurrent urinary tract infections in primary care: a qualitative study of GPs' experiences of conventional management and their attitudes towards possible herbal options

AIM

To explore GPs' experiences of managing recurrent urinary tract infections (RUTIs) and their views on the use of herbal medicines for this condition.

BACKGROUND

RUTIs are an important problem commonly managed in primary care. Antibiotic prophylaxis is an effective treatment for acute infections but growing microbial resistance, adverse effects, and the lack of sustained long-term benefits mean that novel treatments are required. There are a number of promising reports of herbal medicines being used to treat RUTIs.

METHODS

A total of 15 GPs (seven female; aged 34-59 years; in practice from 3 to 31 years) were purposively sampled and took part in semi-structured face-to-face and telephone interviews. Interviews were digitally recorded, transcribed, and analysed using inductive thematic analysis. Data collection and analysis proceeded iteratively to allow emerging themes to inform subsequent interviews.

FINDINGS

Participants were aware of the disabling effect of RUTIs on women's lives. GPs experienced significant challenges in their management of RUTIs with decisions about the provision of antibiotics being particularly complex. While some participants were open to the possibility of herbal treatment options they required more research into effectiveness and safety, better regulation of herbal practitioners, and assurance about herbal quality control and potential herb-drug interactions.

Uropathogenic E. coli infection provokes epigenetic downregulation of CDKN2A (p16INK4A) in uroepithelial cells

Host cell and bacterial factors determine severity and duration of infections. To allow for bacteria pathogenicity and persistence, bacteria have developed mechanisms that modify expression of host genes involved in cell cycle progression, apoptosis, differentiation and the immune response. Recently, Helicobacter pylori infection of the stomach has been correlated with epigenetic changes in the host genome. To identify epigenetic changes during Escherichia coli induced urinary tract infection (UTI), we developed an in vitro model of persistent infection of human uroepithelial cells with uropathogenic E. coli (UPEC), resulting in intracellular bacteria colonies. Cells inoculated with FimH-negative E. coli (N-UPEC) that are not internalized and non-inoculated cells were used as controls. UPEC infection significantly induced de novo methyltransferase (DNMT) activity (12.5-fold P=0.002 UPEC vs non-inoculated and 250-fold P=0.001 UPEC vs N-UPEC inoculated cells) and Dnmt1 RNA expression (6-fold P=0.04 UPEC vs non-inoculated cells) compared with controls. DNMT1 protein levels were significantly increased in three uroepithelial cell lines (5637, J82, HT-1197) in response to UPEC infection as demonstrated by confocal analysis. Real-time PCR analysis of candidate genes previously associated with bacteria infection and/or innate immunity, revealed UPEC-induced downregulation of the tumor suppressor gene CDKN2A (3.3-fold P=0.007 UPEC vs non-inoculated and 3.3-fold P=0.001 UPEC vs N-UPEC) and the DNA repair gene MGMT (9-fold P=0.03 UPEC vs non-inoculated). Expression of CDH1, MLH1, DAPK1 and TLR4 was not affected. Pyrosequencing of CDKN2A and MGMT CpG islands revealed increased methylation in CDKN2A exon 1 (3.8-fold P=0.04 UPEC vs N-UPEC and UPEC vs non-inoculated). Methylation of MGMT was not affected. UPEC-induced methylation of CDKN2A exon 1 may increase bladder cancer and presage UTI risk, and be useful as a biological marker for UTI susceptibility or recurrence.

Innate and adaptive immune responses in the urinary tract

As new and intriguing details of how uropathogens initiate infections and persist within the urinary tract have emerged, so has important information regarding how the immune system functions within the urinary tract. Recent studies have revealed the existence of a multifaceted innate immune response triggered by Toll-like receptor (TLR) 4 on superficial bladder epithelial cells directed at clearing infection by Gram negative pathogens. Other studies have reported that the adaptive immune response in the urinary tract is effective and that vaccines comprised of bacterial virulence factors or whole dead bacteria can evoke protective immunity against urinary tract infections (UTIs) in animals and humans. As antibiotic therapy becomes increasingly ineffective, modulating the innate and adaptive immune system in the urinary tract using TLR4 ligands and other immunomodulators may become viable options to combat UTIs.

Bacterial penetration of bladder epithelium through lipid rafts

Type 1 fimbriated Escherichia coli represents the most common human uropathogen, owing much of its virulence to invasion of the uroepithelium, which is highly impermeable due to the preponderance of uroplakins and highly ordered lipid components. We sought to elucidate the molecular basis for E. coli invasion of the bladder epithelium by employing human 5637 bladder epithelial cells, and we found the following: (i) intracellular E. coli associated with caveolae and lipid raft components; (ii) RNA(i) reduction of caveolin-1 expression inhibited bacterial invasion; (iii) a signaling molecule required for E. coli invasion was located in lipid rafts and physically associated with caveolin-1; (iv) bacterial invasion was inhibited by lipid raft disrupting/usurping agents. In the mouse bladder, the E. coli type 1 fimbrial receptor, uroplakin Ia, was located in lipid rafts, and lipid raft disruptors inhibited E. coli invasion. Cumulatively, E. coli uroepithelial invasion occurs through lipid rafts, which, paradoxically, contribute to bladder impermeability.

Epidemiology of urinary tract infections: transmission and risk factors, incidence, and costs

Uropathogenic E. coli have special features that allow them to take advantage of the bladder environment. There UPEC can grow to substantial numbers in pure culture that are shed frequently into the environment and have a high probability of transmission to other hosts. A better understanding of the transmission system and the host and bacterial factors influencing transmission is essential for the identification of effective prevention strategies. Although the risk of severe morbidity among otherwise healthy populations is low, the incidence is high. Further, the potential impact of antibiotic treatment on the emergence of increasingly antibiotic-resistant UPEC (the resistant mechanisms that may be transmitted to other bowel inhabitants) is high. The benefits of successfully preventing UTI are substantial.

Urinary tract infections: what's new?

PURPOSE

This review provides practicing urologists with important basic information about urinary tract infections (UTIs) that can be applied to everyday clinical problems.

MATERIALS AND METHODS

A review is presented of provocative and controversial concepts in the current literature.

RESULTS

Bacterial virulence mechanisms are critical for overcoming the normal host defenses. Increasing antimicrobial resistance of uropathogens has led to reconsideration of traditional treatment recommendations in many areas. For effective patient management the first issue is to define complicating urological factors. Managing complicated urinary tract infections, particularly in urology, is determined by clinical experience to define the pertinent anatomy and to determine the optimal interventions. New clinical data are summarized on UTIs in long-term care patients, behavioral risks for UTI in healthy women and anatomical differences associated with an increased risk for UTI. The rationale is presented for UTI prophylaxis using cranberry juice, immunization and bacterial interference. Current treatment trends for UTI include empiric therapy (without urine culture and sensitivity testing), short-course therapy, patient-administered (self-start) therapy and outpatient therapy for uncomplicated pyelonephritis.

CONCLUSIONS

Recommendations for treating patients with UTIs have changed based on basic science and clinical experience.