The Role of Urinary Microbiota in Lower Urinary Tract Dysfunction: A Systematic Review

Clinical Microbiome Testing for Urology

The urine culture is imperfect, and a series of alternative approaches are in development to assist in diagnosis, treatment, and prevention of urinary tract infection (UTI). Culture-independent approaches typically do not distinguish between viable and nonviable bacteria, and are generally not included in current clinical guidance. Next-generation sequencing may play an important future role in precise targeting of antibiotic treatment of asymptomatic bacteriuria prior to endourologic surgery or in pregnancy. Future studies are needed to determine whether microbiota modulation could prevent UTI. Possible modulation mechanisms may include fecal microbiota transplant, application of topical vaginal estrogen or probiotics, and bacteriophage therapy.

Associations of overactive bladder (OAB) with suicidal ideation incidence and all-cause mortality among the U.S. population

BACKGROUND

Few studies have explored the correlation between overactive bladder (OAB) and suicidal ideation. This study aims to investigate the association between OAB and suicidal ideation, as well as the relationship between OAB and all-cause mortality among individuals with suicidal ideation.

METHODS

Data from the 2005-2018 National Health and Nutrition Examination Survey (NHANES) were analyzed using cross-sectional and cohort study designs. Weighted multivariable logistic regression models were used to examine the association between OAB and suicidal ideation. Kaplan-Meier curves and weighted multivariable Cox proportional hazards models assessed the relationship between OAB and all-cause mortality among those with suicidal ideation. Interaction analyses on subgroups were conducted to validate the findings. Mediation analysis was performed to examine the effect of depression on the relationship between OAB and suicidal ideation.

RESULTS

Among 33,426 participants aged ≥ 20 years, 1,290 (3.8%) reported suicidal ideation. After adjusting for potential confounders, participants with OAB were 2.57 times more likely to have suicidal ideation (P < 0.001). Over an average follow-up of 87 months, 197 participants with suicidal ideation died. The Cox model revealed that participants with OAB had a 3.08 times higher risk of death (P = 0.006). Kaplan-Meier curves indicated higher survival rates for non-OAB participants. Mediation analysis indicates that depression significantly mediates the relationship between OAB and suicidal ideation, with a mediation proportion of 75.25% (P < 0.001).

CONCLUSIONS

OAB is positively associated with the incidence of suicidal ideation and all-cause mortality among participants with suicidal ideation. Additionally, the association between OAB and suicidal ideation is mediated by depression.

Comparison of the urinary microbiome in men who have sex with men with and without Chlamydia trachomatis infection

PURPOSE

The urinary tract is colonized by microbial communities that impact urinary health. Previous studies have suggested that the bacterial composition of the male urinary microbiota is related to STIs. This study assessed the bacterial composition of the urinary microbiome in South African MSM with and without C. trachomatis.

METHODS

This study used urine samples from MSM attending care at the King Edward VIII hospital and the Aurum Institute in Durban, South Africa. A total of 200 samples were tested for C. trachomatis infection using the Applied Biosystems™ TaqMan® Assays. Urinary microbiomes of 23 samples were characterized using 16 S rRNA (V3 and V4) gene sequencing on the Illumina MiSeq platform.

RESULTS

Bacterial taxonomic analysis showed a high abundance of Streptococcus, Corynebacterium, and Staphylococcus in all the sequenced samples. Moreover, Prevotella and Lactobacillus were detected in urine samples of MSM. Alpha diversity metrics showed a slight increase in microbial diversity in C. trachomatis positive samples; however, this was not significant (ANOVA, P > 0.05). Principal coordinates analysis (PCoA) showed that the microbiome of C. trachomatis infected MSM was not clearly different from those uninfected. Distinct bacterial communities were not detected between positive and negative samples (PERMANOVA F1,22= 1.0284, R2 = 0.047%, P = 0.385).

CONCLUSION

Most microbiome studies on MSM to date have focused on the gut microenvironment. Few studies, however, have provided data regarding the normal composition of the male urethral microbiomes or if these microbiomes are associated with male STIs. This study adds to the growing body of knowledge highlighting the urinary microbiome in MSM.

Causal effects of gut microbiota on risk of interstitial cystitis: a two-sample Mendelian randomization study

Background

The correlation between gut microbiota and interstitial cystitis has garnered significant attention in previous studies. Nevertheless, the causal relationship between them remains to be clarified.

Methods

Genetic variation serves as a tool in Mendelian randomization analyses, facilitating the inference of causal relationships between exposure factors and disease outcomes. In this study, summary statistics derived from a comprehensive genome-wide association study conducted by the MiBioGen consortium were utilized as exposure factors, while interstitial cystitis data sourced from the GWAS Catalog served as the disease outcome. Then, a two-sample Mendelian randomization analysis was performed by applying inverse variance-weighted, MR-Egger, Weighted Median, Simple Mode, and Weighted Mode. In addition, heterogeneity and horizontal pleiotropy were excluded by sensitivity analysis.

Results

IVW results confirmed that genus Haemophilus (OR = 2.20, 95% CI: 1.16-4.15, p = 0.015), genus Butyricimonas (OR = 2.26, 95% CI: 1.15-4.45, p = 0.018), genus Bacteroides (OR = 4.27, 95% CI: 1.36-13.4, p = 0.013) and Coprococcus1 (OR = 3.39, 95% CI: 1.28-8.99, p = 0.014) had a risk effect on interstitial cystitis. Sensitivity analysis did not find outlier SNPs.

Conclusion

Our analysis has identified a causal relationship between specific genera and interstitial cystitis. However, further validation through randomized controlled trials is essential to substantiate these findings.

A systematic and comprehensive review of the role of microbiota in urinary chronic pelvic pain syndrome

BACKGROUND

Many genitourinary tract disorders could be attributed partly to the microbiota. This study sought to conduct a systematic review of the role of the microbiota in urinary chronic pelvic pain syndrome (UCPPS).

METHODS

We searched Embase, Scopus, Web of Science, and PubMed with no time, language, or study type restrictions until December 1, 2023. The JBI Appraisal Tool was used to assess the quality of the studies. Study selection followed the PRISMA statement. Studies addressing microbiome variations among patients suffering from interstitial cystitis/bladder pain syndrome (IC/BPS) or chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and a control group were considered eligible.

RESULTS

A total of 21 studies (1 UCPPS, 12 IC/BPS, and 8 CP/CPPS) comprising 1125 patients were enrolled in our final data synthesis. It has been shown that the reduced diversity and discrepant composition of the gut microbiota may partly be attributed to the UCPPS pathogenesis. In terms of urine microbiota, some operational taxonomic units were shown to be elevated, while others became less abundant. Furthermore, various bacteria and fungi are linked to specific clinical features. Few investigations denied UCPPS as a dysbiotic condition.

CONCLUSIONS

Urinary and intestinal microbiota appear to be linked with UCPPS, comprising IC/BPS and CP/CPPS. However, given the substantial disparity of published studies, a battery of prospective trials is required to corroborate these findings.

The Role of the Urobiome in Kidney Transplantation: A Systematic Review

Background

The urinary microbiome, also known as the urobiome, was traditionally considered sterile. However, emerging evidence suggests its presence in the urinary tract. Urobiome dysbiosis has been associated with various urologic conditions, making it a topic of interest also in kidney transplantation. This systematic review examines the evidence of urobiome changes in kidney transplant recipients (KTRs).

Methods

Systematic literature searches in the PubMed and SCOPUS databases.

Results

Of the 770 articles identified, 8 met the inclusion criteria. The urobiome showed reduced diversity in KTRs compared with healthy controls and patients on dialysis. Proteobacteria enrichment was associated with graft stability or spontaneous tolerance in KTRs without immunological events. Kidney interstitial fibrosis and tubular atrophy were associated with changes in resident urinary microbes and increased pathogenic bacteria. Additionally, KTRs with chronic allograft dysfunction had a higher prevalence of Corynebacterium.

Conclusions

The review highlights the importance of studying the urobiome in KTRs and its potential impact on transplant outcomes. The field remains largely unexplored, and further research is needed to establish consistent study designs and objectives. Future studies could lead to biomarker discovery, personalized therapies, and improved outcomes and graft survival in KTRs.

The human microbiome and benign prostatic hyperplasia: Current understandings and clinical implications

The research of the human microbiome in the preceding decade has yielded novel perspectives on human health and diseases. Benign prostatic hyperplasia (BPH) is a common disease in middle-aged and elderly males, which negatively affects the life quality. Existing evidence has indicated that the human microbiome, including urinary, intra-prostate, gut, oral and blood microbiome may exert a significant impact on the natural progression of BPH. The dysbiosis of the microbiome may induce inflammation at either a local or systemic level, thereby affecting the BPH. Moreover, metabolic syndrome (MetS) caused by the microbiome can also be involved in the development of BPH. Additionally, alterations in the microbiome composition during the senility process may serve as another cause of the BPH. Here, we summarize the influence of human microbiome on BPH and explore how the microbiome is linked to BPH through inflammation, MetS, and senility. In addition, we propose promising areas of investigation and discuss the implications for advancing therapeutic approaches.

Clinical relevance of expanded quantitative urine culture in health and disease

"Expanded quantitative urine culture (EQUC)" is an enhanced culture protocol for the detection of viable microbes in urine specimens. Using a large volume of urine and different sets of cultural conditions, EQUC is able to uncover a wide range of bacteria and fungi (yeasts) that were otherwise undetected by the standard urinary culture. In addition to common urinary pathogens, EQUC has been shown to detect emerging and new pathogens, and commensal microbiota. Although the usefulness of EQUC protocol in clinical set up has not yet been fully established, recent studies have demonstrated that EQUC can provide valuable information regarding symptom resolution, treatment responses and diagnosis of major urinary disorders including urinary tract infections, urinary incontinence and other lower urinary tract symptoms. EQUC may also help in evaluating the utility of beneficial microbiota as biotherapeutics. This narrative minireview describes the current research findings regarding the clinical utility of EQUC in characterizing the role of urinary microbiome and uropathogens in health and disease. The literature which are written in English, available on "PubMed" and contain any of the terms- "expanded quantitative urine culture", "enhanced quantitative urine culture" and "EQUC" in the abstracts were used as the source articles to prepare this minireview.

Differences in the Urinary Microbiome of Patients with Overactive Bladder Syndrome with and without Detrusor Overactivity on Urodynamic Measurements

INTRODUCTION

It has been hypothesized that the urinary microbiome might play an important role in OAB. Studies have been conducted on the association between OAB symptoms and the microbiome, although a possible causality still has to be determined.

MATERIAL AND METHODS

In this study, 12 female patients, ≥18 years of age, with 'OAB DO+' and 9 female patients with 'OAB DO-' were included. Patients were excluded if they met one of the following exclusion criteria: bladder tumors and previous bladder operations; sacral neuromodulation; injection of Botox in the bladder; and TOT or TVT operations. Urine samples were collected and stored with patient informed consent and with the approval of the Hospital Ethical Review Board (Arnhem-Nijmegen). All OAB patients underwent urodynamics before collecting urine samples, and the diagnosis of detrusor overactivity was confirmed by two individual urologists. In addition, samples from 12 healthy controls who did not undergo urodynamic evaluation were analyzed. The 16S rRNA V1-V2 region amplification and gel electrophoresis were used to determine the microbiota.

RESULTS

12 of the OAB patients had DO shown on their urodynamic studies; the remaining 9 patients had a normoactive detrusor on their urodynamic measurements. Overall, there were no substantial differences among the demographic characteristics of the subjects. The samples were classified as the following: 180 phyla, 180 classes, 179 orders, 178 families, 175 genera, and 138 species. The least commonly observed phyla were Proteobacteria, with an average presence of 10%, followed by Bacteroidetes with 15%, Actinobacteria with 16%, and Firmicutes with 41%. Most of the sequences could be classified according to the genus level for each sample.

DISCUSSION

Significant differences were observed in the urinary microbiome of patients with overactive bladder syndrome who have detrusor overactivity on urodynamics compared to OAB patients without detrusor overactivity and matched controls. OAB patients with detrusor overactivity have a significantly less diverse microbiome and show a higher proportion of Lactobacillus, particularly Lactobacillus iners. The results imply that the urinary microbiome could be involved in the pathogenesis of a specific phenotype of OAB. The urinary microbiome could be a new starting point to study the causes and treatments of OAB.

Profiling the Urobiota in a Pediatric Population with Neurogenic Bladder Secondary to Spinal Dysraphism

The human bladder has been long thought to be sterile until that, only in the last decade, advances in molecular biology have shown that the human urinary tract is populated with microorganisms. The relationship between the urobiota and the development of urinary tract disorders is now of great interest. Patients with spina bifida (SB) can be born with (or develop over time) neurological deficits due to damaged nerves that originate in the lower part of the spinal cord, including the neurogenic bladder. This condition represents a predisposing factor for urinary tract infections so that the most frequently used approach to treat patients with neurogenic bladder is based on clean intermittent catheterization (CIC). In this study, we analyzed the urobiota composition in a pediatric cohort of patients with SB compared to healthy controls, as well as the urobiota characteristics based on whether patients received CIC or not.

Urinary tract infection in patients with lower urinary tract dysfunction

Lower urinary tract dysfunction (LUTD) is becoming more common in aging societies worldwide. In patients with LUTD, the risk of urinary tract infection (UTI) rises due to several distinct mechanisms, including easy bacterial access to the urinary tract, impaired bacterial washout, and an impaired innate defense system. The pathophysiology of LUTD varies depending on whether it is neurogenic or non-neurogenic, as well as by gender; therefore, the etiology and characteristics of UTI differ according to the type of LUTD. Patients with neurogenic LUTD, especially those with spinal cord injury, have a high risk of febrile UTI, and strict bladder management is required to prevent UTI. Clean intermittent catheterization with or without appropriate pharmacological therapy is also strongly recommended for patients with neurogenic LUTD at risk of febrile UTI, unable to void, or with high post-void residual volume. In contrast, both male and female patients with non-neurogenic LUTD have a lower risk of symptomatic UTI. There is insufficient evidence for non-neurogenic LUTD regarding the association between symptomatic UTI but not asymptomatic bacteriuria and LUTD severity, including the presence of post-void residual volume, or whether therapeutic intervention for LUTS reduces the incidence of UTI, particularly in male patients. In this narrative review, we aimed to highlight the pathogenesis, epidemiology, and management of UTI in patients with LUTD.

Is there a difference in fecal microbiota of children with and without voiding dysfunction?

OBJECTIVE

Voiding dysfunction (VD), which encompasses many urinary symptoms that are not caused by neurological or anatomical anomalies, is a frequently encountered functional urinary bladder disorder in children. It was reported that there was an association between lower urinary tract symptoms and fecal microbiota in adult patients. Therefore, we aimed to investigate the differences in fecal microbiota between children with or without VD.

METHODS

Two patient groups, including 30 patients, were compared. Group 1 included patients with VD, while Group 2 consisted of healthy children. All study participants were asked to fill lower urinary tract and voiding dysfunction symptom score forms with the assistance of their parents. Subsequently, uroflowmetry tests and postvoiding residual urine measurements were performed. Fresh stool samples were collected from all children and analyzed by polymerase chain reaction. General bacterial load and presence of Roseburia intestinalis, Clostridium difficile, Fusobacterium nucleatum, and Bacteroides clarus were tested.

RESULTS

The two groups were significantly different regarding general bacterial load; the presence of Fusobacterium nucleatum. Clostridium difficile and Bacteroides clarus was not detected in the fresh stool samples of the patients in Group 2; the counts of Roseburia intestinalis were less in Group 1 than in Group 2, although there was no statistically significant difference. There was a negative correlation between symptom scores, general bacterial load, and the presence of Fusobacterium nucleatum. However, there was no correlation between the presence of Roseburia intestinalis and symptom scores.

CONCLUSIONS

There is a potential relationship between VD and a deviation in the fecal microbiota in the pediatric population.

Localization and potential role of prostate microbiota

Introduction

We aimed to clarify the presence and localization of the prostate microbiota and examine its association with benign prostate enlargement (BPE).

Methods

The microbiota of prostate tissues and catheterized urine from 15 patients were analyzed by 16S metagenomic analysis and compared to show that the prostate microbiota was not a contaminant of the urinary microbiota. Fluorescence in situ hybridization (FISH) and in situ hybridization (ISH) using the specific probe for eubacteria was performed on prostate tissue to show the localization of bacteria in the prostate. The BPE group was defined as prostate volume ≥30 mL, and the non-BPE group as prostate volume <30 mL. The microbiota of the two groups were compared to clarify the association between prostate microbiota and BPE.

Results

Faith's phylogenetic diversity index of prostate tissue was significantly higher than that of urine (42.3±3.8 vs 25.5±5.6, P=0.01). Principal coordinate analysis showed a significant difference between the microbiota of prostate tissue and catheterized urine (P<0.01). FISH and ISH showed the presence of bacteria in the prostatic duct. Comparison of prostate microbiota between the BPE and non-BPE groups showed that the Chao1 index of the BPE group was significantly lower than that of the latter [142 (50-316) vs 169 (97-665), P=0.047] and the abundance of Burkholderia was significantly higher in the BPE group than in the latter.

Conclusions

We demonstrated that the prostate microbiota was located in the prostatic duct and reduced diversity of prostate microbiota was associated with BPE, suggesting that prostate microbiota plays a role in BPE.

Possibilities and limitations of using low biomass samples for urologic disease and microbiome research

With the dogma of sterile urine no longer held as truth, numerous studies have implicated distinct changes in microbial diversity and composition to diseased subgroups in both benign and malignant urological diseases, ranging from overactive bladder to bladder and prostate cancer. Further facilitated by novel and effective techniques of urine culture and sequencing, analysis of the genitourinary microbiome holds high potential to identify biomarkers for disease and prognosis. However, the low biomass of samples included in microbiome studies of the urinary tract challenge researchers to draw definitive conclusions, confounded by technical and procedural considerations that must be addressed. Lack of samples and adequate true negative controls can lead to overestimation of microbial influence with clinical relevance. As such, results from currently available studies and assessment of their limitations required a thorough understanding. The purpose of this narrative review was to summarize notable microbiome studies in the field of urology with a focus on significant findings and limitations of study design. Methodological considerations in future research are also discussed.

Urinary microbiota and bladder cancer: A systematic review and a focus on uropathogens

The higher incidence of bladder cancer in men has long been attributed to environmental factors, including smoking. The fact that the sex ratio of bladder cancer remains consistently weighted toward men despite the remarkable increase in the prevalence of smoking among women suggests that other risk factors influence the incidence rates of bladder cancer. These factors may include the urinary microbiota. In this study, we provide a review of recent literature regarding the association between bladder cancer and changes in the urinary microbiota, with a focus on the potential role of uropathogens in the microbiota and sex in bladder cancer. Four databases were systematically searched up to 31 March 2021 to identify human case-controlled studies that evaluated the relationship between urinary microbiota and bladder cancer. We combined bacterial taxa that were significantly higher or lower in the bladder cancer group in each study in the urine (voided and catheterized) and tissue samples. Findings from sixteen eligible studies were analyzed. The total sample size of the included studies was 708 participants, including 449 (63.4 %) bladder cancer patients and 259 (36.6 %) participants in the control group. When considering only the taxa that have been reported in at least two different studies, we observed that with regards to neoplastic tissues, no increased taxa were reported, while Lactobacillus (2/5 of the studies on tissue samples) was increased in nonneoplastic-tissue compared to neoplastic-tissues at the genus level. In catheterized urine, Veillonella (2/3 of the studies on catheterized urine) was increased in bladder cancer patients compared to the control groups at the genus level. In voided urine, Acinetobacter, Actinomyces, Aeromonas, Anaerococcus, Pseudomonas, and Tepidomonas were increased in the bladder cancer patients, while Lactobacillus, Roseomonas, Veillonella were increased in the control groups. Regarding gender, the genus Actinotignum was increased in female participants while Streptococcus was increased in male participants at the genus level. Regarding potential uropathogens in the urinary microbiota, Escherichia-Shigella provided conflicting results, with both showing higher and lower levels in the bladder cancer groups. However, the family Enterobacteriaceae was lower in the bladder cancer groups than in the control groups. In conclusion, there is no consensus on what taxa of the urinary microbiota are associated with bladder cancer according to the sample type. Findings on the potential role of uropathogens in the urinary microbiota in bladder cancer remain inconsistent. Due to the limited number of studies, further studies on urinary microbiota and bladder cancer are needed to address this issue. Given that all publications concerning the urinary microbiota and bladder cancer have been performed using 16S rRNA gene sequencing, we propose that polyphasic approaches, including culture-dependent techniques, may allow for a more comprehensive investigation of the urinary microbiota associated with bladder cancer.

Uncovering the role of urinary microbiota in urological tumors: a systematic review of literature

PURPOSE

Urinary microbiota has been found to play a key role in numerous urological diseases. The aim of this systematic review is to depict the role of urinary microbiota in the pathogenesis, diagnosis, prognosis, and treatment of urological tumors, including bladder cancer (BCa), prostate cancer (PCa) and renal cell carcinoma (RCC).

METHODS

A systematic PubMed and Scopus search was undergone from inception through June 2021 for studies investigating urinary microbiota alterations in urological tumors. Study selection followed the PRISMA statement. Phylum, family, genus and species of each bacterium in cancer patients and controls were recorded.

RESULTS

Twenty-one studies with 1194 patients (748 cancer patients and 446 controls) were included in our final analysis. Certain bacterial phylum, family, genus, and species were more predominant in each of BCa, PCa and RCC patients compared to controls. Abundance and specificity of urinary microbiota were prognosticators for: (1) recurrence, distinguishing recurrent from non-recurrent BCa, (2) disease stage, distinguishing non-muscle invasive from muscle invasive BCa, and (3) disease grade, distinguishing high- vs. low-grade PCa and BCa. Dietary, environmental and geographic patterns influenced urinary microbiota. Urinary microbiota of benign prostatic hyperplasia was different from PCa.

CONCLUSION

Urological cancer patients have an altered urinary microbiota compared to controls. This may predict recurrence, disease stage and disease grade of these tumors. Further prospective studies are needed to depict a potential influence on therapeutic outcomes.

Local induction of bladder Th1 responses to combat urinary tract infections

Given the high frequency of urinary tract infections (UTIs) and their recurrence, there is keen interest in developing effective UTI vaccines. Currently, most vaccine studies, including those in humans, involve parenteral vaccination aimed at evoking and sustaining elevated levels of systemic antibody directed at the uropathogens. In view of recent reports of aberrant Th2-biased bladder immune responses to infection, we hypothesized that immunizing mice intravesically with antigens from uropathogenic Escherichia coli (UPEC) combined with a Th1-skewing adjuvant could correct this defect and promote protection against UTIs. Here we report that compared with mice immunized subcutaneously with this vaccine combination, intravesically immunized mice were markedly more protected from UTIs because of their distinctive ability to recruit Th1 cells into the bladder. This mode of vaccination was effective even in mice that experienced multiple UTIs and displayed pronounced aberrant bladder immune responses. Thus, intravesical vaccination with one or more UPEC antigens to induce bladder Th1 responses represents a superior strategy to combat UTIs, especially in UTI-prone subjects.

Bacterial colonization of bladder urothelial cells in women with refractory Detrusor Overactivity: the effects of antibiotic therapy

Bacterial infection may have a pathophysiological role in refractory Detrusor Overactivity (DO). The aim of this study was to observe any impact of antibiotic therapy upon bacterial colonization of urothelial cells, and to determine whether a relationship existed between colonization and symptom severity. Mid-stream urine samples were collected as part of a clinical trial of antibiotics in women with refractory DO. Wright stained urothelial cells were categorized according to the degree of bacterial colonization as; 'clear' (free of bacteria), or as associated with bacteria that were 'adjacent' to the cell or 'intracellular' at low or high density. The average percentages were compared with routine microbiology cultures, over the 26 week trial, and with patient clinical outcome measures of DO severity. In patients receiving placebo, 'high-density intracellular bacteria' significantly increased during urinary tract infection (P = 0.0008). In antibiotic patients, 'clear' cells were more prevalent. Amoxicillin & Clavulanic Acid significantly decreased bacterial colonization within urothelial cells, suggesting that these antibiotics possess the greatest intracellular efficacy. 'High-density intracellular bacteria' positively correlated with symptom severity, measured by leakage on pad test (P = 0.014), leaks per day (P = 0.004), and voids per day (P = 0.005). Thus, by decreasing high density intracellular bacteria, antibiotic treatment may improve the refractory DO condition.

Recurrent urinary tract infection: Association of clinical profiles with urobiome composition in women

AIMS

Clinical profiles of women with recurrent urinary tract infection (RUTI) are correlated with their urinary microbes.

METHODS

This IRB-approved, cross-sectional study enrolled adult women with RUTI. Urine samples (catheterized and voided) underwent culture by expanded quantitative urine culture (EQUC) and standard urine culture (SUC) methods. A validated symptom questionnaire, relevant clinical variables, and EQUC were used to identify symptom clusters and detect associations with specific urinary microbes.

RESULTS

Most (36/43) participants were postmenopausal; the average age was 67 years. 51% reported vaginal estrogen use; 51% reported sexual activity. Although single symptoms were not associated with specific urinary microbes, EQUC results were correlated with five distinct clinical profile clusters: Group A: odor, cloudiness, and current vaginal estrogen use (no culture result association). Group B: frequency, low back pain, incomplete emptying, and vaginal estrogen (significantly increased proportion of Lactobacillus-positive cultures). Group C: pain/burning, odor, cloudiness, and urgency (high proportions of UTI-associated microbe-positive cultures). Group D: frequency, urgency, pain/burning, and current vaginal estrogen use (increased number of no growth cultures). Group E: frequency, urgency, pain/burning, odor, overactive bladder, and sexually active (significantly increased proportion of Klebsiella-positive cultures).

CONCLUSIONS

Distinct clinical profiles are associated with specific urinary microbes in women with RUTI. Refined assessments of clinical profiles may provide useful insights that could inform diagnostic and therapeutic considerations.

Bacterial Colonization as a Possible Source of Overactive Bladder Symptoms in Pediatric Patients: A Literature Review

Overactive Bladder (OAB) is a common condition that is known to have a significant impact on daily activities and quality of life. The pathophysiology of OAB is not completely understood. One of the new hypothetical causative factors of OAB is dysbiosis of an individual urinary microbiome. The major aim of the present review was to identify data supporting the role of bacterial colonization in overactive bladder symptoms in children and adolescents. The second aim of our study was to identify the major gaps in current knowledge and possible areas for future clinical research. There is a growing body of evidence indicating some relationship between qualitative and quantitative characteristics of individual urinary microbiome and OAB symptoms in adult patients. There are no papers directly addressing this issue in children or adolescents. After a detailed analysis of papers relating urinary microbiome to OAB, the authors propose a set of future preclinical and clinical studies which could help to validate the concept in the pediatric population.

A New Gold Rush: A Review of Current and Developing Diagnostic Tools for Urinary Tract Infections

Urinary tract infections (UTIs) are one of the most common infections in the United States and consequently are responsible for significant healthcare expenditure. The standard urine culture is the current gold standard for diagnosing urinary tract infections, however there are limitations of the test that directly contribute to increased healthcare costs. As a result, new and innovative techniques have been developed to address the inefficiencies of the current standard-it remains to be seen whether these tests should be performed adjunctly to, or perhaps even replace the urine culture. This review aims to analyze the advantages and disadvantages of the newer and emerging diagnostic techniques such as PCR, expanded quantitative urine culture (EQUC), and next generation sequencing (NGS).

Treatment of Non-neurogenic Lower Urinary Tract Symptoms-A Review of Key Publications from 2018 Onward

CONTEXT

A considerable number of studies addressing the management of lower urinary tract symptoms (LUTS) have been published since 2018.

OBJECTIVE

To review the key studies involving pharmacological and neuromodulation treatment of LUTS published from 2018 onward.

EVIDENCE ACQUISITION

We followed the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) statement. We conducted an Embase/PubMed search of English literature with the words "OAB" or "LUTS" matched with several different treatment modalities. The search ranged between January 2018 and January 2020. All retrieved papers were first reviewed by title and abstract, yielding a total of 236 papers. Additional manuscripts, such as those presented at major meetings, were also included. After revision, 46 publications were included.

EVIDENCE SYNTHESIS

Papers on β3-adrenoreceptor agonists were most abundant. The efficacy and safety of mirabegron in monotherapy and combination therapy were further confirmed by large observational studies and randomized control trials, including one carried out in elderly patients. The use of vibegron for overactive bladder (OAB) was effective and safe in pivotal clinical trials. More database analyses confirm the risk of dementia associated with long-term use of anticholinergics. Onabotulinum toxinA (OnabotA) and sacral neuromodulation provided similar improvement for incontinence in OAB patients at a 2-yr follow-up. Retrospective studies show that OnabotA is effective in men with OAB. New subcutaneous or transcutaneous devices for tibial nerve stimulation were investigated. The potential role of gene therapy in LUTS was assessed in a pilot study.

CONCLUSIONS

Important progresses occurred in the pharmacological and neuromodulation treatments of LUTS, which may change clinical practice. Inoculation of gene vectors was investigated for the first time.

PATIENT SUMMARY

The investigation in the therapeutic field of lower urinary tract symptoms is active. The search for the best option for each patient continues. This systematic review summarizes the findings of the most recent and relevant studies in the field.

The microbiome in urological diseases

Due to the rapid development of next-generation sequencing, it has become possible to obtain information on the sequences of all genes in a specific microbiome. The detection of bacteria in patients with no urinary tract infections indicated that the dogma that “urine is sterile” was false, leading to active research regarding the roles of the urinary microbiome in the human urinary tract. Here, we present a review of the current literature regarding the role of the microbiome in urology.

A highly polarized TH2 bladder response to infection promotes epithelial repair at the expense of preventing new infections

Urinary tract infections (UTIs) typically evoke prompt and vigorous innate bladder immune responses, including extensive exfoliation of the epithelium. To explain the basis for the extraordinarily high recurrence rates of UTIs, we examined adaptive immune responses in mouse bladders. We found that, following each bladder infection, a highly T helper type 2 (TH2)-skewed immune response directed at bladder re-epithelialization is observed, with limited capacity to clear infection. This response is initiated by a distinct subset of CD301b+OX40L+ dendritic cells, which migrate into the bladder epithelium after infection before trafficking to lymph nodes to preferentially activate TH2 cells. The bladder epithelial repair response is cumulative and aberrant as, after multiple infections, the epithelium was markedly thickened and bladder capacity was reduced relative to controls. Thus, recurrence of UTIs and associated bladder dysfunction are the outcome of the preferential focus of the adaptive immune response on epithelial repair at the expense of bacterial clearance.

Altered gut microbiome associated with overactive bladder and daily urinary urgency

PURPOSE

To explore associations between the gut microbiome and overactive bladder (OAB) with daily urinary urgency among individuals reporting this diagnosis within a single community.

METHODS

This cross-sectional study surveyed 1113 individuals who participated in the Iwaki Health Promotion Project in Japan. OAB was defined as urinary urgency at least once per week and an Overactive Bladder Symptom Score (OABSS) of ≥ 3. OAB with urinary urgency at least once a day was defined as daily urgency. The gut microbiomes were assessed by next-generation sequencing of 16S rRNA genes extracted from fecal samples. The participants were divided into two groups: OAB-daily urgency and non-OAB. Cases were selected for inclusion on the basis of 1:1 propensity score matching; we assigned 58 individuals to each group (23 men and 35 women) for our analysis.

RESULTS

Individuals reporting OAB with daily urinary urgency demonstrated a lower bacterial diversity between individuals (Bray-Curtis distance 0.48 vs. 0.53, P < 0.001); the results cluster differently in the non-OAB groups. The relative abundance of genus Bifidobacterium was significantly lower among those reporting daily urgency (2.41% vs. 4.23%, P = 0.014). By contrast, the relative abundance of genus Faecalibacterium (9.25% vs. 6.26%, P = 0.006) was significantly higher in this group.

CONCLUSION

We observed significant differences in gut microbial contents and specific bacterial genera in association with OAB with daily urgency. Further study will be necessary to assess causal relationships between the gut microbiome and OAB.

Urinary microbiome in uncomplicated and interstitial cystitis: is there any similarity?

PURPOSE

Acute/uncomplicated cystitis is the most common bacterial infection causing inflammation in the bladder tissues and predominantly diagnosed in women. Interstitial cystitis may too, cause inflammation in the bladder but its etiology has been elusive. Even though the site and symptoms of both diseases are largely shared, state of the urinary microbiome in these disorders have not been comparatively evaluated before. The purpose of this review is to assess and qualitatively compare structure and composition of the urinary microbiome in acute/uncomplicated cystitis and interstitial cystitis.

METHODS AND RESULTS

The available literature in MEDLINE are extensively searched using keywords and screened. Pertinent evidence is carefully assessed and synthesized. We included the original studies with a cohort of medically stable, non-pregnant women with otherwise functionally normal urinary tract and excluded the original articles if the infection in a patient's cohort is accompanied by urinary syndromes such as incontinence and overactive bladder syndrome. A total of six original papers reporting on the urinary microbiome in acute cystitis and nine papers on the interstitial cystitis met the selection criteria.

CONCLUSION

The evidence we have gleaned from the literature on the urinary microbiome associated with the acute and interstitial cystitis does not point to convergence of microbiome similarities between the two diseases. More studies with direct sampling of the bladder tissues besides sampling bladder surfaces are warranted for accurate comparison of microbiome similarity between the two conditions. The future research on interstitial cystitis microbiome should include stratified cohorts with prospective design.

Does preoperative urine culture still play a role in predicting post-PCNL SIRS? A retrospective cohort study

There is controversy regarding the predicting value of preoperative urine culture for post-percutaneous nephrolithotripsy (PCNL) infection. The purpose of our study was to re-evaluate the importance of preoperative urine culture for developing post-PCNL systemic inflammatory response syndrome (SIRS) in China. A total of 303 patients undergone PCNL from March 2012 to January 2018 were recruited. Urine tests, urine cultures and the perioperative data were prospectively recorded and analyzed. 95 patients (31.4%) were identified with positive preoperative urine cultures. Female patients had significantly higher rate of urine cultures positivity than that in male patients (42.9% vs. 21.5%, p < 0.01). Escherichia coli was the most common organism (56 cases, 58.9%) in patients with positive urine cultures and 35.7% of E. coli-positive patients developed SIRS after PCNL. Even with intensive perioperative prophylaxis, patients with positive urine cultures had a higher rate of post-PCNL SIRS than those patients with negative urine cultures (p = 0.043). On multivariable analysis, preoperative positive urine cultures (OR 1.943, 95% CI 1.11-3.39, p = 0.019), preoperative neutrophils (OR 1.228, 95% CI 1.07-1.41, p = 0.003), intraoperative pyonephrosis (OR 3.37, 95% CI 1.44-9.71, p = 0.01) and postoperative hospitalization (OR 1.154, 95% CI 1.05-1.28, p = 0.005) were independent risk factors for postoperative SIRS. These results demonstrated that preoperative urine culture still played a role in predicting post-PCNL SIRS, but it was unable to prevent the occurrence of SIRS even with intensive perioperative prophylaxis based on urine culture results. Further studies are required to explore the predicting role of advanced preoperative bacterial detecting techniques in post-PCNL infectious complications.

The impact of microbiome in urological diseases: a systematic review

OBJECTIVE

The term microbiome is used to signify the ecological community of commensal, symbiotic, and pathogenic microorganisms that share our body space, in which there were increasing evidences to suggest that they might have potential roles in various medical conditions. While the study of microbiome in the urinary system is not as robust as the systems included in the Human Microbiome Project, there are still evidences in the literature showing that microbiome may have a role in urological diseases. Therefore, we would like to perform a systematic review on the topic and summarize the available evidence on the impact of microbiome on urological diseases.

METHODOLOGY

This review was performed according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. After screening 589 abstracts and including additional studies (such as references from review papers), 76 studies were included for review and discussion.

RESULTS

Studies had suggested that there were correlations of microbiome of different body cavities (e.g., fecal, urinary and seminal fluid) with urological diseases. Also, different diseases would have different microbiome profile in different body cavities. Unfortunately, the studies on the association of microbiome and urological diseases were still either weak or inconsistent.

CONCLUSION

Studies suggested that there might be some relationship between microbiome and various urological diseases. However, further large-scale studies with control of confounding factors should be performed under a standardized methodology in order to have better understanding of the relationship. Also, more standardized reporting protocol for microbiome studies should be considered for better communications in future studies.

Urinary Biomarkers in Overactive Bladder: Revisiting the Evidence in 2019

CONTEXT

In overactive bladder (OAB), after an initial outbreak of research, it is more consensual that biomarkers may be better used to phenotype patients. Herein, we revisit this topic, including some of the most promising biomarkers.

OBJECTIVE

To provide a comprehensive analysis of the actual role of biomarkers in OAB.

EVIDENCE ACQUISITION

A PubMed-based literature search was conducted, including the most relevant articles published in the last 15 yr, on nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), adenosine triphosphate (ATP), genomics, and microbiota as OAB biomarkers. Articles with no full text available or not written in English were excluded. Additional reviews were included.

EVIDENCE SYNTHESIS

Urinary NGF, BDNF, and ATP are increased in many OAB patients. These biomarkers can help identify OAB phenotypes and select the ideal candidates for new therapies directed to neurotrophic and purinergic pathways. Circulating urinary miRNA may be useful for establishing the ideal moment for bladder outlet obstruction relief and will eventually lead to the development of therapeutic agents that inhibit or reverse fibrotic pathways in the bladder. Urinary microbiota seems to be related to OAB symptoms, in particular urgency urinary incontinence, and may have strong implications in the prevention, diagnosis, and treatment of OAB.

CONCLUSIONS

In the future, physicians may consider the use of biomarkers to identify distinct OAB phenotypes, with distinct causal mechanisms, selecting patients for specific target therapies with expected better outcomes.

PATIENT SUMMARY

Overactive bladder biomarkers can be useful for phenotype patients and for selecting more effective target therapies.