Direct Detection of Tissue-Resident Bacteria and Chronic Inflammation in the Bladder Wall of Postmenopausal Women with Recurrent Urinary Tract Infection

Comparing costs associated with management of antibiotic-recalcitrant recurrent urinary tract infections for one year pre- and post-electrofulguration

INTRODUCTION

To quantify and compare recurrent urinary tract infection costs between 1 year before and 1 year after electrofulguration.

METHODS

Following IRB approval, a well-characterized cohort of non-neurogenic women with >3 symptomatic urinary tract infections (UTIs)/year, a negative upper and lower urinary tract evaluation, and inflammatory bladder lesions (cystitis) on office cystoscopy who underwent fulguration of these lesions was analyzed. Cost of visits, imaging, labs, and medications were summed for 1-year pre- and post-fulguration using the Medicare Physician Fee Schedule, local pharmacy pricing, and institutional expenses. Before fulguration, all patients underwent clinic visit, noninvasive flow study, and flexible cystoscopy, and post-fulguration, 6-week follow-up visit and 6-month cystoscopy.

RESULTS

Ninety-three women met study criteria (mean age 64), with 100% 1-year follow-up. Before fulguration, 73% of patients used daily antibiotic suppression, 6% self-start antibiotics, and 5% postcoital prophylaxis. Some also used vaginal estrogens (17%), urinary analgesics (13%), and cranberry or d-mannose supplements (7%). At 1 year post-fulguration, 82% had 0-1 infections and no cystoscopy evidence of cystitis, while 14% required additional fulguration for new cystitis sites and recurrent infections. Patients had on average 0.7 infections in the 1-year post-fulguration, which was significantly lower than pre-fulguration (p < 0.05). Mean 1-year pre-fulguration cost was $1328 (median $1071, range $291-$5564). Mean 1-year post-fulguration cost was $617 (median $467, range $275-$4580). On average, post-fulguration costs were $710 lower than pre-EF (p < 0.05).

CONCLUSION

For women with antibiotic-refractory recurrent urinary tract infections and cystoscopy evidence of cystitis, fulguration was associated with a significant reduction in UTI-related costs in the 1-year post-fulguration.

Bacterial species cultured after electrofulguration in women with a history of antibiotic-recalcitrant urinary tract infections frequently compare with pre-fulguration findings: a pilot study

Electrofulguration (EF) of areas of chronic cystitis in women with antibiotic-recalcitrant recurrent urinary tract infections (RUTIs) can result in improvement of their urinary tract infections (UTIs). We compared urine culture (UC) findings in patients before and after EF, as well as how they vary with cystitis stage at the time of EF, to evaluate for persistent species. After obtaining institutional review board approval, we retrospectively reviewed a prospectively maintained database of EF patients for those with positive UC findings in the 3-6 months preceding EF. Patient pre-EF UC was then compared with first positive UC after EF prompted by a new symptomatic UTI episode, with the hypothesis that the same species will be identified before and after EF. Exclusion criteria included UC from outside institution, neurogenic bladder, and need for catheterization. Ninety-nine women with pre- or post-EF UC-recorded organisms met the study criteria. The median age was 65 years (interquartile range 64-74), with a median time to first positive culture following fulguration of 9.7 months. For 26 patients with positive cultures both pre- and post-EF, the same organism was present in both cultures in 73% of the patients, with predominantly Escherichia coli. EF was effective at reducing the rate of UTIs in this population. For women undergoing EF for antibiotic-recalcitrant RUTIs and associated chronic cystitis lesions, 73% of those with a UC obtained at the time of a first symptomatic recurrent UTI episode post-EF expressed the same organism as before EF. Further study is needed to better understand the evolution of the microbiome post-EF.IMPORTANCEAmong women who experience a recurrent urinary tract infection after a fulguration procedure on areas of chronic cystitis in their bladder, there are no data available on whether the bacterial species found in urine cultures are the same or different from those present before fulguration. By removing the inflamed surface layer of cystitis during fulguration, it is possible that the procedure unmasks deep-seated bacteria. The bacterial kingdom in the bladder wall of these chronically infected women may be different from what is expressed sporadically in urine cultures. Confirming prior studies, we found that fulguration in women with antibiotic-recalcitrant recurrent urinary tract infections and cystitis lesions was effective at reducing the rate of urinary tract infections. At the time of a first symptomatic recurrent UTI episode post-fulguration, 73% expressed the same organism in urine culture as before fulguration. Further study is needed to better understand the evolution of the microbiome post-EF. This article evaluates persistent infections after electrofulguration of areas with chronic cystitis in post-menopausal women with antibiotic-recalcitrant recurrent urinary tract infections. Pre-fulguration urine cultures were compared with the first positive urine culture prompted by a new symptomatic UTI episode after electrofulguration, with the hypothesis that the same species will be identified before and after the fulguration procedure. Electrofulguration was effective at reducing the rate of UTIs in this population. However, 73% of those with a urine culture obtained at the time of a first symptomatic recurrent UTI episode post-electrofulguration expressed the same organism (predominantly Escherichia coli) as before the fulguration procedure. Further study is needed to better understand the evolution of the microbiome after electrofulguration.

Bladder-resident bacteria associated with increased risk of recurrence after electrofulguration in women with antibiotic-recalcitrant urinary tract infection

Background

Antibiotic-recalcitrant recurrent urinary tract infection (rUTI) is has become increasingly observed in postmenopausal women. Therefore, when standard antibiotic therapies have failed, some elect electrofulguration (EF) of areas of chronic cystitis when detected on office cystoscopy. EF is thought to remove tissue-resident bacteria that have been previously detected in the bladder walls of postmenopausal women with rUTI. We hypothesized that increased bladder bacterial burden may be associated with incomplete rUTI resolution following EF.

Methods

Following IRB approval, bladder biopsies were obtained from 34 consenting menopausal women electing EF for the advanced management of rUTI. 16S rRNA FISH was performed using both universal and Escherichia probes and tissue-resident bacterial load was quantified. Time to UTI relapse after EF was recorded during a six-month follow-up period and the association of bladder bacterial burden and clinical covariates with UTI relapse was assessed.

Results

We observed bladder-resident Escherichia in 52% of all participants and in 92% of participants with recent E. coli UTI. Time-to-relapse analysis revealed that women with high bladder bacterial burden as detected by the universal probe had a significantly ( p =0.035) higher risk of UTI within six months of EF (HR=3.15, 95% CI: 1.09-9.11). Interestingly, bladder-resident Escherichia was not significantly associated ( p =0.26) with a higher risk of UTI relapse (HR= 2.14, 95% CI: 0.58-7.90).

Conclusions

We observed that total bladder bacterial burden was associated with a 3.1x increased risk of rUTI relapse within six months. Continued analysis of the relationship between bladder bacterial burden and rUTI outcomes may provide insight into the management of these challenging patients.

Systematic Review of the Global Literature on Uncomplicated Recurrent Urinary Tract Infections in Women: Underscoring Major Heterogeneity

OBJECTIVE

To examine the global literature database on uncomplicated recurrent urinary tract infections (rUTI), this systematic review assesses the availability of rUTI data based on geographic region and elucidates the current state of research and gaps in knowledge.

METHODS

The databases PubMed, Embase, WHO Global Index Medicus, and SciELO were searched for keywords related to rUTI between 2000 and 2023. Three independent reviewers screened studies restricted to female participants age ≥18 years with uncomplicated rUTIs. Studies were excluded if they did not provide a definition for rUTI or did not cite or report an estimate for rUTI prevalence. The review was registered in PROSPERO and conformed to PRISMA guidelines.

RESULTS

The search yielded 2947 studies of which 124 were ultimately included. Convenience samples were used for 91% of studies and sample sizes were 30% n <50, 29% n = 50-99, 22% n = 100-199, 36% n ≥200. Most studies were conducted in Europe (41%) or North America (39%), were prospective (52%), at tertiary centers (49%) and included all ages ≥18 (60%). The most common definition for rUTI was 2 UTI/6 m or 3 UTI/1y (62%). Regardless of study location, most studies cited prevalence estimates for rUTI derived from U.S.-based populations.

CONCLUSION

This study represents the first formal investigation of the global literature base on uncomplicated rUTI. Studies on rUTIs are globally of small scale and definitions used for rUTI are heterogeneous. More studies are needed to ascertain the true prevalence of rUTI outside of North America and Europe.

Variability in cell division among anatomical sites shapes Escherichia coli antibiotic survival in a urinary tract infection mouse model

Urinary tract infection (UTI), mainly caused by Escherichia coli, are frequent and have a recurrent nature even after antibiotic treatment. Potential bacterial escape mechanisms include growth defects, but probing bacterial division in vivo and establishing its relation to the antibiotic response remain challenging. Using a synthetic reporter of cell division, we follow the temporal dynamics of cell division for different E. coli clinical strains in a UTI mouse model with and without antibiotics. We show that more bacteria are actively dividing in the kidneys and urine compared with the bladder. Bacteria that survive antibiotic treatment are consistently non-dividing in three sites of infection. Additionally, we demonstrate how both the strain in vitro persistence profile and the microenvironment impact infection and treatment dynamics. Understanding the relative contribution of the host environment, growth heterogeneity, non-dividing bacteria, and antibiotic persistence is crucial to improve therapies for recurrent infections.

Likelihood of Antimicrobial Resistance in Urinary E coli Isolates among US Female Patients with Recurrent vs Non-Recurrent Uncomplicated Urinary Tract Infection

OBJECTIVE

To assess the relative likelihood of antimicrobial resistance (AMR) and multi-drug resistance (MDR) among E coli isolates from outpatients with recurrent versus non-recurrent uncomplicated urinary tract infection (uUTI).

METHODS

In this retrospective observational US cohort study, female outpatients (≥12 years) with uUTI, positive E coli culture, and treated with ≥1 oral antibiotic within ±5 days of diagnosis were grouped into recurrent and non-recurrent uUTI cohorts per their UTI history (past 12 months). AMR to specific drug classes was evaluated at index. Univariable and multivariable logistic regression models estimated the likelihood of not-susceptible E coli isolates (AMR/MDR) among patients with recurrent uUTI versus non-recurrent uUTI.

RESULTS

Recurrent (N = 12,234) and non-recurrent (N = 68,033) uUTI cohorts had similar distributions (race, ethnicity, region). Patients with recurrent uUTI had a higher prevalence of E coli resistance to trimethoprim-sulfamethoxazole (21.8% vs 18.7%) and fluoroquinolones (14.2% vs 8.6%), and more isolates were extended-spectrum β-lactamase-producing (5.9% vs 4.1%) compared to non-recurrent uUTI patients. Patients with recurrent uUTI had a higher likelihood (odds ratio [95% confidence interval]) of any AMR (1.28 [1.22-1.34]), single drug-class resistance (1.18 [1.12-1.24]), and resistance to 2 (1.53 [1.41-1.67]) or ≥3 drug classes (1.70 [1.48-1.96]) (all P <.001).

CONCLUSION

This study delineated the likelihood of AMR and MDR among E coli isolates from patients with recurrent versus non-recurrent uUTI. While some treatment guidelines support empiric therapy in recurrent uUTI, the increased likelihood of resistance among these patients suggests that culture and susceptibility testing should be undertaken to inform recurrent uUTI treatment.

VesiX cetylpyridinium chloride is rapidly bactericidal and reduces uropathogenic Escherichia coli bladder epithelial cell invasion in vitro

Management of urinary tract infection (UTI) in postmenopausal women can be challenging. The recent rise in resistance to most of the available oral antibiotic options together with high recurrence rate in postmenopausal women has further complicated treatment of UTI. As such, intravesical instillations of antibiotics like gentamicin are being investigated as an alternative to oral antibiotic therapies. This study evaluates the efficacy of the candidate intravesical therapeutic VesiX, a solution containing the cationic detergent Cetylpyridinium chloride, against a broad range of uropathogenic bacterial species clinically isolated from postmenopausal women with recurrent UTI (rUTI). We also evaluate the cytotoxicity of VesiX against cultured bladder epithelial cells and find that low concentrations of 0.0063% and 0.0125% provide significant bactericidal effect toward diverse bacterial species including uropathogenic Escherichia coli (UPEC), Klebsiella pneumoniae, Enterococcus faecalis, Pseudomonas aeruginosa, and Proteus mirabilis while minimizing cytotoxic effects against cultured 5637 bladder epithelial cells. Lastly, to begin to evaluate the potential utility of using VesiX in combination therapy with existing intravesical therapies for rUTI, we investigate the combined effects of VesiX and the intravesical antibiotic gentamicin. We find that VesiX and gentamicin are not antagonistic and are able to reduce levels of intracellular UPEC in cultured bladder epithelial cells.

IMPORTANCE

When urinary tract infections (UTIs), which affect over 50% of women, become resistant to available antibiotic therapies dangerous complications like kidney infection and lethal sepsis can occur. New therapeutic paradigms are needed to expand our arsenal against these difficult to manage infections. Our study investigates VesiX, a Cetylpyridinium chloride (CPC)-based therapeutic, as a candidate broad-spectrum antimicrobial agent for use in bladder instillation therapy for antibiotic-resistant UTI. CPC is a cationic surfactant that is FDA-approved for use in mouthwashes and is used as a food additive but has not been extensively evaluated as a UTI therapeutic. Our study is the first to investigate its rapid bactericidal kinetics against diverse uropathogenic bacterial species isolated from postmenopausal women with recurrent UTI and host cytotoxicity. We also report that together with the FDA-approved bladder-instillation agent gentamicin, VesiX was able to significantly reduce intracellular populations of uropathogenic bacteria in cultured bladder epithelial cells.

Comparative genomic analysis of uropathogenic Escherichia coli strains from women with recurrent urinary tract infection

Introduction

Recurrent urinary tract infections (RUTIs) caused by uropathogenic Escherichia coli are costly public health problems impacting patients' quality of life.

Aim

In this work, a comparative genomics analysis of three clinical RUTI strains isolated from bladder biopsy specimens was performed.

Materials and methods

One hundred seventy-two whole genomes of urinary tract E. coli strains were selected from the NCBI database. The search for virulence factors, fitness genes, regions of interest, and genetic elements associated with resistance was manually carried out. The phenotypic characterization of antibiotic resistance, haemolysis, motility, and biofilm formation was performed. Moreover, adherence and invasion assays with human bladder HTB-5 cells, and transmission electron microscopy (TEM) were performed.

Results

The UTI-1_774U and UTI-3_455U/ST1193 strains were associated with the extraintestinal pathotypes, and the UTI-2_245U/ST295 strain was associated with the intestinal pathotype, according to a phylogenetic analysis of 172 E. coli urinary strains. The three RUTI strains were of clinical, epidemiological, and zoonotic relevance. Several resistance genes were found within the plasmids of these strains, and a multidrug resistance phenotype was revealed. Other virulence genes associated with CFT073 were not identified in the three RUTI strains (genes for type 1 and P fimbriae, haemolysin hlyA, and sat toxin). Quantitative adherence analysis showed that UTI-1_774U was significantly (p < 0.0001) more adherent to human bladder HTB-5 cells. Quantitative invasion analysis showed that UTI-2_245U was significantly more invasive than the control strains. No haemolysis or biofilm activity was detected in the three RUTI strains. The TEM micrographs showed the presence of short and thin fimbriae only in the UTI-2_245U strain.

Conclusion

The high variability and genetic diversity of the RUTI strains indicate that are a mosaic of virulence, resistance, and fitness genes that could promote recurrence in susceptible patients.

D-Mannose reduces cellular senescence and NLRP3/GasderminD/IL-1β-driven pyroptotic uroepithelial cell shedding in the murine bladder

Aging is a risk factor for disease via increased susceptibility to infection, decreased ability to maintain homeostasis, inefficiency in combating stress, and decreased regenerative capacity. Multiple diseases, including urinary tract infection (UTI), are more prevalent with age; however, the mechanisms underlying the impact of aging on the urinary tract mucosa and the correlation between aging and disease remain poorly understood. Here, we show that, relative to young (8-12 weeks) mice, the urothelium of aged (18-24 months) female mice accumulates large lysosomes with reduced acid phosphatase activity and decreased overall autophagic flux in the aged urothelium, indicative of compromised cellular homeostasis. Aged bladders also exhibit basal accumulation of reactive oxygen species (ROS) and a dampened redox response, implying heightened oxidative stress. Furthermore, we identify a canonical senescence-associated secretory phenotype (SASP) in the aged urothelium, along with continuous NLRP3-inflammasome- and Gasdermin-D-dependent pyroptotic cell death. Consequently, aged mice chronically exfoliate urothelial cells, further exacerbating age-related urothelial dysfunction. Upon infection with uropathogenic E. coli, aged mice harbor increased bacterial reservoirs and are more prone to spontaneous recurrent UTI. Finally, we discover that treatment with D-mannose, a natural bioactive monosaccharide, rescues autophagy flux, reverses the SASP, and mitigates ROS and NLRP3/Gasdermin/interleukin (IL)-1β-driven pyroptotic epithelial cell shedding in aged mice. Collectively, our results demonstrate that normal aging affects bladder physiology, with aging alone increasing baseline cellular stress and susceptibility to infection, and suggest that mannose supplementation could serve as a senotherapeutic to counter age-associated urothelial dysfunction.

Impact of microbiota and host immunologic response on the efficacy of anticholinergic treatment for urgency urinary incontinence

INTRODUCTION AND HYPOTHESIS

Studies within the past decade have suggested associations among composition of the urinary microbiota, local immune responses, and urinary incontinence symptoms. To investigate these relationships, we evaluated the structure of the urinary microbiome, local inflammatory markers, and patient responses prior to and at 6-weeks after treatment with anticholinergic medication for urgency urinary incontinence (UUI).

METHODS

Using a prospective pilot study, we enrolled women who presented with UUI symptoms and were prescribed treatment with anticholinergics. Catheterized urine samples were collected from participants at their baseline and 6-week follow-up visits for microbiological (standard and 16S rRNA gene phylotyping analyses) and cytokine analysis along with the UDI-6 questionnaire and 2-day bladder diary.

RESULTS

Patients were Caucasian, post- menopausal, with a median age of 64 and median BMI of 30.1 kg/m2. Among the patients, 75% had UUI symptoms for less than 2 years, but with a frequency of at least a few times a week or every day. Most women were prescribed 10 mg oxybutynin ER daily at enrollment. Patients had varied urinary microbiota by culture and 16S phylotyping, with species of Lactobacillus being the most common, in six samples, in addition to taxa associated with Enterococcus, Staphylococcus, and mixed flora. Cytokine levels showed no differences before and after treatment with anticholinergics, nor correlation with urinary bacteria or microbiome composition.

CONCLUSIONS

Our pilot study suggests factors in addition to the urinary microbiome and local immune responses may be involved in patients' response to anticholinergics for UUI.

Bladder-draining lymph nodes support germinal center B cell responses during urinary tract infection in mice

Bacterial urinary tract infections (UTIs) are both common and exhibit high recurrence rates in women. UTI healthcare costs are increasing due to the rise of multidrug-resistant (MDR) bacteria, necessitating alternative approaches for infection control. Here, we directly observed host adaptive immune responses in acute UTI. We employed a mouse model in which wild-type C57BL/6J mice were transurethrally inoculated with a clinically relevant MDR UTI strain of uropathogenic Escherichia coli (UPEC). Firstly, we noted that rag1-/- C57BL/6J mice harbored larger bacterial burdens than wild-type counterparts, consistent with a role for adaptive immunity in UTI control. Consistent with this, UTI triggered in the bladders of wild-type mice early increases of myeloid cells, including CD11chi conventional dendritic cells, suggesting possible involvement of these professional antigen-presenting cells. Importantly, germinal center B cell responses developed by 4 weeks post-infection in bladder-draining lymph nodes of wild-type mice and, although modest in magnitude and transient in nature, could not be boosted with a second UTI. Thus, our data reveal for the first time in a mouse model that UPEC UTI induces local B cell immune responses in bladder-draining lymph nodes, which could potentially serve to control infection.

A human urothelial microtissue model reveals shared colonization and survival strategies between uropathogens and commensals

Urinary tract infection is among the most common infections worldwide, typically studied in animals and cell lines with limited uropathogenic strains. Here, we assessed diverse bacterial species in a human urothelial microtissue model exhibiting full stratification, differentiation, innate epithelial responses, and urine tolerance. Several uropathogens invaded intracellularly, but also commensal Escherichia coli, suggesting that invasion is a shared survival strategy, not solely a virulence hallmark. The E. coli adhesin FimH was required for intracellular bacterial community formation, but not for invasion. Other shared lifestyles included filamentation (Gram-negatives), chaining (Gram-positives), and hijacking of exfoliating cells, while biofilm-like aggregates were formed mainly with Pseudomonas and Proteus. Urothelial cells expelled invasive bacteria in Rab-/LC3-decorated structures, while highly cytotoxic/invasive uropathogens, but not commensals, disrupted host barrier function and strongly induced exfoliation and cytokine production. Overall, this work highlights diverse species-/strain-specific infection strategies and corresponding host responses in a human urothelial microenvironment, providing insights at the microtissue, cell, and molecular level.

The distinct transcriptome of virulence-associated phylogenetic group B2 Escherichia coli

Escherichia coli strains of phylogenetic group B2 are often associated with urinary tract infections (UTIs) and several other diseases. Recent genomic and transcriptomic analyses have not suggested or identified specific genes required for virulence, but have instead suggested multiple virulence strategies and complex host-pathogen interactions. Previous analyses have not compared core gene expression between phylogenetic groups or between pathogens and nonpathogens within phylogenetic groups. We compared the core gene expression of 35 strains from three phylogenetic groups that included both pathogens and nonpathogens after growth in a medium that allowed comparable growth of both types of strains. K-means clustering suggested a B2 cluster with 17 group B2 strains and two group A strains; an AD cluster with six group A strains, five group D strains and one B2 strain; and four outliers which included the highly studied model uropathogenic E. coli strains UTI89 and CFT073. Half of the core genes were differentially expressed between B2 and AD cluster strains, including transcripts of genes for all aspects of macromolecular synthesis-replication, transcription, translation, and peptidoglycan synthesis-energy metabolism, and environmental-sensing transcriptional regulators. Notably, core gene expression between nonpathogenic and uropathogenic transcriptomes within phylogenetic groups did not differ. If differences between pathogens and nonpathogens exist, then the differences do not require transcriptional reprogramming. In summary, B2 cluster strains have a distinct transcription pattern that involves hundreds of genes. We propose that this transcription pattern is one factor that contributes to virulence. IMPORTANCE Escherichia coli is a diverse species and an opportunistic pathogen that is associated with various diseases, such as urinary tract infections. When examined, phylogenetic group B2 strains are more often associated with these diseases, but the specific properties that contribute to their virulence are not known. From a comparative transcriptomic analysis, we found that group B2 strains grown in a nutrient-rich medium had a distinct transcription pattern, which is the first evidence that core gene expression differs between phylogenetic groups. Understanding the consequences of group B2 transcription pattern will provide important information on basic E. coli biology, the basis for E. coli virulence, and possibly for developing therapies for a majority of urinary tract infections and other group B2-associated diseases.

Inter-species diversity and functional genomic analyses of closed genome assemblies of clinically isolated, megaplasmid-containing Enterococcus raffinosus Er676 and ATCC49464

Enterococcus raffinosus is an understudied member of its genus possessing a characteristic megaplasmid contributing to a large genome size. Although less commonly associated with human infection compared to other enterococci, this species can cause disease and persist in diverse niches such as the gut, urinary tract, blood and environment. Few complete genome assemblies have been published to date for E. raffinosus . In this study, we report the complete assembly of the first clinical urinary E. raffinosus strain, Er676, isolated from a postmenopausal woman with history of recurrent urinary tract infection. We additionally completed the assembly of clinical type strain ATCC49464. Comparative genomic analyses reveal inter-species diversity driven by large accessory genomes. The presence of a conserved megaplasmid indicates it is a ubiquitous and vital genetic feature of E. raffinosus . We find that the E. raffinosus chromosome is enriched for DNA replication and protein biosynthesis genes while the megaplasmid is enriched for transcription and carbohydrate metabolism genes. Prophage analysis suggests that diversity in the chromosome and megaplasmid sequences arises, in part, from horizontal gene transfer. Er676 demonstrated the largest genome size reported to date for E. raffinosus and the highest probability of human pathogenicity. Er676 also possesses multiple antimicrobial resistance genes, of which all but one are encoded on the chromosome, and has the most complete prophage sequences. Complete assembly and comparative analyses of the Er676 and ATCC49464 genomes provide important insight into the inter-species diversity of E. raffinosus that gives it its ability to colonize and persist in the human body. Investigating genetic factors that contribute to the pathogenicity of this species will provide valuable tools to combat diseases caused by this opportunistic pathogen.

Urinary Tract Infection and Microbiome

Urinary tract infection is one of the most common bacterial infections and can cause major burdens, not only to individuals but also to an entire society. Current knowledge of the microbial communities in the urinary tract has increased exponentially due to next-generation sequencing and expanded quantitative urine culture. We now acknowledge a dynamic urinary tract microbiome that we once thought was sterile. Taxonomic studies have identified the normal core microbiota of the urinary tract, and studies on the changes in microbiome due to sexuality and age have set the foundation for microbiome studies in pathologic states. Urinary tract infection is not only caused by invading uropathogenic bacteria but also by changes to the uromicrobiome milieu, and interactions with other microbial communities can also contribute. Recent studies have provided insights into the pathogenesis of recurrent urinary tract infections and antimicrobial resistance. New therapeutic options for urinary tract infections also show promise; however, further research is needed to fully understand the implications of the urinary microbiome in urinary tract infections.

Tissue-resident memory T cells mediate mucosal immunity to recurrent urinary tract infection

Urinary tract infection (UTI) is one of the most prevalent human bacterial infections. New therapeutic approaches, including vaccination and immunotherapy, are urgently needed to combat the rapid global dissemination of multidrug-resistant uropathogens. Development of therapies is impeded by an incomplete understanding of memory development during UTI. Here, we found that reducing bacterial load early in infection, by reducing the inoculum or with antibiotics after infection, completely abrogated the protective memory response. We observed a mixed T helper (T_H) cell polarization, composed of T_H1, T_H2, and T_H17 T cells, among T cells infiltrating the bladder during primary infection. Thus, we hypothesized that reducing antigen load altered T_H cell polarization, leading to poor memory. Unexpectedly, however, T_H cell polarization was unchanged in these scenarios. Instead, we uncovered a population of tissue-resident memory (T_RM) T cells that was significantly reduced in the absence of sufficient antigen. Demonstrating that T_RM cells are necessary for immune memory, transfer of lymph node- or spleen-derived infection-experienced T cells to naïve animals did not confer protection against infection. Supporting that T_RM cells are sufficient to protect against recurrent UTI, animals depleted of systemic T cells, or treated with FTY720 to block memory lymphocyte migration from lymph nodes to infected tissue, were equally protected compared with unmanipulated mice against a second UTI. Thus, we uncovered an unappreciated key role for T_RM cells in the memory response to bacterial infection in the bladder mucosa, providing a target for non-antibiotic-based immunotherapy and/or new vaccine strategies to prevent recurrent UTI.

Escherichia coli-associated follicular cystitis in dogs: Clinical and pathologic characterization

BACKGROUND

Follicular cystitis is an uncommon inflammatory change in the urinary bladder wall characterized by the formation of tertiary lymphoid structures (TLSs) in the submucosa.

OBJECTIVES

To characterize clinical and pathologic features of follicular cystitis in dogs and to explore in situ distribution and possible role of Escherichia coli as an associated cause.

ANIMALS

Eight dogs diagnosed with follicular cystitis and 2 control dogs.

METHODS

Retrospective descriptive study. Dogs diagnosed with follicular cystitis (macroscopic follicular lesions in the urinary bladder mucosa and histopathologic detection of TLSs in bladder wall biopsies) were identified from medical records. Paraffin embedded bladder wall biopsies were subject to in situ hybridization for E. coli 16SrRNA identification.

RESULTS

Follicular cystitis was diagnosed in large breed (median weight 24.9 kg, interquartile range [IQR] 18.8-35.4 kg) female dogs with a history of chronic recurrent urinary tract infections (UTIs; median duration of clinical signs 7 months, IQR 3-17 months; median number of previous UTIs 5, IQR 4-6). Positive E. coli 16SrRNA signal was detected within developing, immature and mature TLSs in 7/8 dogs, through submucosal stroma in 8/8 dogs and within the urothelium in 3/8 dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Chronic inflammation associated with an intramural E. coli infection in the urinary bladder wall represents a possible triggering factor for the development of follicular cystitis.

Effective Treatments of UTI—Is Intravesical Therapy the Future?

Urinary tract infection (UTI) afflicts millions of patients globally each year. While the majority of UTIs are successfully treated with orally administered antibiotics, the impact of oral antibiotics on the host microbiota is under close research scrutiny and the potential for dysbiosis is a cause for concern. Optimal treatment of UTI relies upon the selection of an agent which displays appropriate pharmacokinetic-pharmacodynamic (PK-PD) properties that will deliver appropriately high concentrations in the urinary tract after oral administration. Alternatively, high local concentrations of antibiotic at the urothelial surface can be achieved by direct instillation into the urinary tract. For antibiotics with the appropriate physicochemical properties, this can be of critical importance in cases for which an intracellular urothelial bacterial reservoir is suspected. In this review, we summarise the underpinning biopharmaceutical barriers to effective treatment of UTI and provide an overview of the evidence for the deployment of the intravesical administration route for antibiotics.

Transvaginal ultrasonography for trigonitis diagnosis in women

OBJECTIVE

Chronic trigonitis (CT) is usually diagnosed through cystoscopy which is invasive and expensive. Thus, an accurate non-invasive diagnostic method is necessary. The objective of this study is to determine the efficacy of transvaginal bladder ultrasound (TBU) for CT diagnosis.

METHODS

Between 2012 and 2021, 114 women (17-76 years old) with recurrent urinary tract infection (RUTI) and history of antibiotic resistance were evaluated with TBU by a single ultrasonographer. As a control group, TBU was performed in 25 age-matched women with no previous history of UTI, urological or gynecological conditions. All patients with RUTI had undergone a cystoscopy with biopsy for diagnostic confirmation at the time of trigone cauterization.

RESULTS

Thickening of trigone mucosa (>3 mm) was detected in all patients with RUTI and represented the most relevant criteria for trigonitis diagnosis on TBU. Other TBU findings in CT are: irregular and interrupted mucosa lining (96.4%), free debris in the urine (85.9%), increased blood flow at doppler (81.5%), mucosa shedding and tissue flaps. Biopsy showed CT with erosive pattern (58%) or non-keratinizing metaplasia (42%). Diagnostic agreement index between TBU and cystoscopy was 100%. In the control group, normal trigone mucosa is ultrasonographically regular, continuous, with thickness ≤3 mm and there is no debris in the urine.

CONCLUSIONS

TBU proved to be an efficient, inexpensive and minimally invasive method to diagnose CT. To our knowledge, this is the first article that reports the use of transvaginal ultrasound as an alternative method for diagnosing trigonitis.

Microbiota Ecosystem in Recurrent Cystitis and the Immunological Microenvironment of Urothelium

Urinary tract infections (UTIs) represent one of the most frequent low genital tract diseases in the female population. When UTIs occur with a frequency of at least three times per year or two times in the last six month, we speak of recurrent UTI (rUTI) and up to 70% of women will have rUTI within 1 year. It was previously thought that antibiotic resistance was principally responsible for the recurrence of UTIs, but nowadays new diagnostic technologies have shown the role of microbiota in the pathophysiology of these diseases. Much research has been conducted on the role of gut microbiome in the development of rUTI, while little is known yet about vaginal and urinary microbiome and the possible immunological and microscopical mechanisms through which they trigger symptoms. New discoveries and clinical perspectives are arising, and they all agree that a personalized, multi-modal approach, treating vaginal and urinary dysbiosis, may reduce rUTIs more successfully.

Effects of aging on urinary tract epithelial homeostasis and immunity

A global increase in older individuals creates an increasing demand to understand numerous healthcare challenges related to aging. This population is subject to changes in tissue physiology and the immune response network. Older individuals are particularly susceptible to infectious diseases, with one of the most common being urinary tract infections (UTIs). Postmenopausal and older women have the highest risk of recurrent UTIs (rUTIs); however, why rUTIs become more frequent after menopause and during old age is incompletely understood. This increased susceptibility and severity among older individuals may involve functional changes to the immune system with age. Aging also has substantial effects on the epithelium and the immune system that led to impaired protection against pathogens, yet heightened and prolonged inflammation. How the immune system and its responses to infection changes within the bladder mucosa during aging has largely remained poorly understood. In this review, we highlight our understanding of bladder innate and adaptive immunity and the impact of aging and hormones and hormone therapy on bladder epithelial homeostasis and immunity. In particular, we elaborate on how the cellular and molecular immune landscape within the bladder can be altered during aging as aged mice develop bladder tertiary lymphoid tissues (bTLT), which are absent in young mice leading to profound age-associated change to the immune landscape in bladders that might drive the significant increase in UTI susceptibility. Knowledge of host factors that prevent or promote infection can lead to targeted treatment and prevention regimens. This review also identifies unique host factors to consider in the older, female host for improving rUTI treatment and prevention by dissecting the age-associated alteration of the bladder mucosal immune system.

Recurrent urinary tract infection and estrogen shape the taxonomic ecology and function of the postmenopausal urogenital microbiome

Postmenopausal women are severely affected by recurrent urinary tract infection (rUTI). The urogenital microbiome is a key component of the urinary environment. However, changes in the urogenital microbiome underlying rUTI susceptibility are unknown. Here, we perform shotgun metagenomics and advanced culture on urine from a controlled cohort of postmenopausal women to identify urogenital microbiome compositional and function changes linked to rUTI susceptibility. We identify candidate taxonomic biomarkers of rUTI susceptibility in postmenopausal women and an enrichment of lactobacilli in postmenopausal women taking estrogen hormone therapy. We find robust correlations between Bifidobacterium and Lactobacillus and urinary estrogens in women without urinary tract infection (UTI) history. Functional analyses reveal distinct metabolic and antimicrobial resistance gene (ARG) signatures associated with rUTI. Importantly, we find that ARGs are enriched in the urogenital microbiomes of women with rUTI history independent of current UTI status. Our data suggest that rUTI and estrogen shape the urogenital microbiome in postmenopausal women.

Electro-fulguration for extensive inflammatory bladder lesions in post-menopausal women with antibiotic-recalcitrant recurrent urinary tract infections

INTRODUCTION AND HYPOTHESIS

To evaluate how women with uncomplicated antibiotic-recalcitrant recurrent urinary tract infections (RUTIs) and extensive inflammatory bladder lesions on office cystoscopy responded to electro-fulguration (EF) to eliminate these chronic bladder sites.

METHODS

After IRB approval, a retrospective study of non-neurogenic women with RUTIs, inflammatory lesions on cystoscopy, and who underwent EF was performed. Lesions were classified through a simplified staging system based on the extent of bladder wall involvement. Only those with extensive bladder wall involvement (stages 3 and 4) at the time of EF were analyzed in this report. Six months after EF, an office cystoscopy was performed, with endoscopic success defined as no lesions seen. The primary clinical outcome was number of symptomatic UTIs after EF, defined as cure (0/year), improvement (1-2/year), and failure (≥3/year).

RESULTS

From 2007 to 2019, a total of 57 women met the study criteria, 30 stage 3 and 27 stage 4. Nineteen (63%) were endoscopically successful in stage 3 and 11 (41%) in stage 4. Mean follow-up was 2.9 years (stage 3) and 3.1 years (stage 4). All had at least a 6-month UTI follow-up after the 6 months of office cystoscopy, with 15 patients cured, 37 improved, and 5 failed (all stage 4).

CONCLUSIONS

Although EF only resulted in 63% complete endoscopic resolution, the majority experienced a decrease in the frequency of UTIs, suggesting that EF can be durably effective even in women with very extensive cystitis lesions.

Complete Genome Sequences of Three Lactobacillus gasseri Urine Isolates Obtained from Postmenopausal Women

Lactobacillus gasseri frequently colonizes the lower urinary tract of healthy women. However, the role of L. gasseri in urinary tract health and the genes required for urinary tract colonization are poorly understood. Herein, we announce the complete genome sequences of three Lactobacillus gasseri isolates collected from the urine of postmenopausal women.

Application of metagenomic next-generation sequencing in the diagnosis and treatment of recurrent urinary tract infection in kidney transplant recipients

Background

Rapid and accurate pathogen diagnosis is an urgent unmet clinical need for recurrent urinary tract infection (RUTI) in kidney transplant recipients (KTRs). Metagenomic next-generation sequencing (mNGS) may offer another strategy for diagnosing uropathogens but remains to be studied.

Methods

Nineteen KTRs with RUTI were collected in this study. The uropathogens were detected and compared by mNGS and urine culture, respectively. Modifications of the anti-infection strategy were also assessed.

Results

Rich and diverse pathogens were revealed by mNGS. mNGS was significantly higher than culture in total positive rate (100.0% vs. 31.6%; p < 0.01) and in identification rates for bacteria (89.5% vs. 31.6%; p < 0.01), for viruses (57.9% vs. 0; p < 0.01), and for fungi (42.1% vs. 0; p < 0.01), respectively. mNGS identified a significantly higher proportion of mixed infections than culture (89.5% vs. 10.5%; p < 0.01). The anti-infection therapies were adjusted in two (33.3%) and 12 (76.9%) cases guided by culture and mNGS, respectively.

Conclusion

mNGS has more remarkable etiological diagnostic performance compared with urine culture for KTRs with RUTI to guide anti-infection strategies and, in turn, protect the graft.

Gut-bladder axis enters the stage: Implication for recurrent urinary tract infections

The gut microbiome is a critical modulator of systemic physiology, including infectious disease susceptibility. Although this niche is a reservoir for uropathogenic Escherichia coli, knowledge of its role in urinary tract infections (UTIs) is limited. We discuss two recent studies, Thänert et al. (2022) and Worby et al. (2022), that interrogate the roles of the gut-bladder axis in UTIs.

Gene Expression-Based Functional Differences between the Bladder Body and Trigonal Urothelium in Adolescent Female Patients with Micturition Dysfunction

The aim of this study is to determine the molecular differences between the urothelial transcriptomes of the bladder body and trigone. The transcriptomes of the bladder body and trigonal epithelia were analyzed by massive sequencing of total epithelial RNA. The profiles of urothelial and urinal microbiomes were assessed by amplicon sequencing of bacterial 16S rRNA genes in 17 adolescent females with pain and micturition dysfunction and control female subjects. The RNA sequencing identified 10,261 differentially expressed genes (DEGs) in the urothelia of the bladder body and trigone, with the top 1000 DEGs at these locations annotated to 36 and 77 of the Reactome-related pathways in the bladder body and trigone, respectively. These pathways represented 11 categories enriched in the bladder body urothelium, including extracellular matrix organization, the neuronal system, and 15 categories enriched in the trigonal epithelium, including RHO GTPase effectors, cornified envelope formation, and neutrophil degranulation. Five bacterial taxa in urine differed significantly in patients and healthy adolescent controls. The evaluation of their transcriptomes indicated that the bladder body and trigonal urothelia were functionally different tissues. The molecular differences between the body and trigonal urothelia responsible for clinical symptoms in adolescents with bladder pain syndrome/interstitial cystitis remain unclear.

Reduced urothelial expression of uroplakin-IIIa in cystitis areas in bladders of postmenopausal women with recurrent urinary tract infections: pilot study

PURPOSE

To study human bladder biopsies to investigate urothelial response to UTI, expression of uroplakin, and urothelial response after healing from cystoscopy with electrofulguration (CEF) treatment for antibiotic-recalcitrant RUTI.

METHODS

Following IRB approval, cold cup bladder biopsies from "no cystitis" and "cystitis" regions were obtained from women with antibiotic-recalcitrant rUTI undergoing CEF under anesthesia. "No cystitis" and "cystitis" biopsies from 14 patients (5 had prior CEF, 9 naïve) were analyzed by immunofluorescence (IF) confocal microscopy using antibodies against uroplakin-IIIa. For an additional 6 patients (2 prior CEF, 4 naïve), only "cystitis" area biopsies were taken and analyzed. Cytokeratin 5 (marker for squamous metaplasia) staining was performed on 14 patients.

RESULTS

In healthy tissue, uroplakin-IIIa staining was observed as a contiguous line on the luminal surface of umbrella cells. In "cystitis" areas for 19/20 patients, there was either no uroplakin-IIIa staining observed or spotty (+) staining. The "cystitis" regions of all patients had less intense uroplakin-IIIa staining compared to the matched "no cystitis" area in the same patient. In patients post-CEF but requiring repeat EF for persistent RUTI lesions, healed areas served as control and in 3 of 7 patients no uroplakin-IIIa staining was observed. Squamous metaplasia was observed in 10 patients.

CONCLUSION

In bladders of postmenopausal women with antibiotic-recalcitrant RUTI, areas with visible cystitis expressed less uroplakin-IIIa, supporting the model of urothelial exfoliation in response to UTI.

Cranberry Supplement, D-Mannose, and Other OTC Modalities for Prevention of Recurrent UTI in Women Post-Electrofulguration

Purpose

To assess patient reliance on various over-the-counter (OTC) modalities used for prevention of recurrent urinary tract infection (RUTI) after electrofulguration (EF).

Patients and Methods

Following IRB approval, qualifying women were offered a short survey over the phone by a medical researcher to collect information about their use of various OTC modalities for prophylaxis of RUTI. Data was compared between two cohorts, ≥70 years old and <70 years old, using chi-squared and Student’s t-tests.

Results

From a database of 324 patients, 163 accepted the interview. 17% (28/163) reported current use of cranberry supplements, 10% (16/163) D-mannose supplements, and 42% (69/163) another non-prescription modality for RUTI prophylaxis. The non-geriatric (<70 years old) cohort spent, on average, $80 less annually on cranberry/D-mannose supplements (P=0.043) than the geriatric cohort and were more likely to use non-prescription modalities for the prevention of UTI (52% vs 30%; P=0.0061). Individuals using D-mannose were also much more likely to purchase their product online compared to those using cranberry supplements (85% vs 56%). Across all modalities, the perceived benefit difference in reducing UTI/year ranged from a median of 0 for Pyridium® (phenazopyridine hydrochloride) to four for probiotics, with D-mannose and cranberry at two/year, and those increasing daily fluid consumption at 2.5 fewer UTI/year.

Conclusion

Continued use of non-prescription modalities for RUTI prophylaxis were common among women with an EF history, but varied based on age groups. Across both age cohorts, annual expenditure and perceived benefit also varied among different OTC prophylactic modalities. Awareness of type and method of OTC modality implementation by patients with RUTI is essential to aligning use with current field recommendations.

Multidrug-resistant Uro-associated Escherichia coli Populations and Recurrent Urinary Tract Infections in Patients Performing Clean Intermittent Self-catheterisation

Background

The AnTIC trial linked continuous low-dose antibiotic prophylaxis treatments to a lower incidence of symptomatic urinary tract infections (UTIs) among individuals performing clean intermittent self-catheterisation (CISC).

Objective

To explore potential mechanisms underlying the protective effects of low-dose antibiotic prophylaxis treatments, blood and urine samples and uro-associated Escherichia coli isolates from AnTIC participants were analysed.

Design, setting, and participants

Blood samples (n = 204) were analysed for TLR gene polymorphisms associated with UTI susceptibility and multiple urine samples (n = 558) were analysed for host urogenital responses. E.coli sequence data for 45 temporal isolates recovered from the urine samples of 16 trial participants in the prophylaxis (n = 9) and no-prophylaxis (n = 7) study arms, and characterised by multidrug resistance (MDR), were used to classify individual strains.

Outcome measurements and statistical analysis

TLR polymorphism data were analysed using Poisson regression. Concentrations of urine host defence markers were analysed using linear mixed-effects models, which accounted for repeated urine samples.

Results and limitations

Urine samples from CISC users, irrespective of antibiotic treatment regimens, were associated with robust urothelial innate responses. No links were identified between TLR genotype and CISC user susceptibility to recurrent UTIs. Microbiological study data were limited to the predominant MDR E. coli population; participants prescribed low-dose prophylactic antibiotics were predominantly colonised by a single uro-associated E. coli strain, while participants given acute antibiotic treatments were each colonised by more than one E. coli strain.

Conclusions

Antibiotic treatments did not impact urogenital responses to infection in CISC users. Host genetics in terms of TLR polymorphisms played no role in determining CISC user susceptibility to or protection from recurrent UTIs. Prophylactic antibiotic treatments associated with MDR E. coli were associated with colonisation by stable uro-associated E. coli genotypes.

Patient summary

Our findings show that the natural urogenital defences of clean intermittent self-catheterisation (CISC) users were not impacted by antibiotic treatments. For some CISC users, prophylaxis with low-dose antibiotics selected for a stable, predominantly, Esherichia coli rich uromicrobiota.

Efficacy of antimicrobial intravesical treatment for uncomplicated recurrent urinary tract infections: a systematic review

INTRODUCTION AND HYPOTHESIS

Intravesical antimicrobials (IVA) provide a localized modality of treatment for recurrent urinary tract infections (rUTIs). Owing to the sporadic use of these treatments, we conducted a systematic review on the efficacy of IVA in the management of uncomplicated rUTIs.

METHODS

A systematic review was conducted for all English language articles from inception to April 2021 utilizing the Cochrane and Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards with the following databases: PubMed, OVID Embase, Biomed Central, and Scopus. References were cross-examined for further articles. Risk of bias was assessed in the articles included using the Cochrane and Joanna Briggs Institute tools.

RESULTS

The initial search resulting in 476 titles led to 15 full-text articles. Of the 13 in the final review (2 RCTs), 3 used gentamicin and 10 used hyaluronic acid IVA. These included 764 participants, mostly women, with a mean age range of 27-80 (median: 53.1). There was a reduction in UTI frequency in 12 out of 13 studies, with 10 studies showing a statistically significant decrease. Dosages of 80 mg of gentamicin per instillation and both 40 mg and 800 mg of hyaluronic acid per instillation were found to be effective in reducing the frequency of UTIs in most studies. Eleven participants reported gentamicin-resistant infections after IVA treatment. Despite high levels of bias in selected categories, the 13 studies were designated to be of high quality for inclusion.

CONCLUSIONS

The IVAs gentamicin and hyaluronic acid with chondroitin sulphate demonstrated efficacy in the management of uncomplicated rUTIs, mostly in women.

THE MOST COMMON UROLOGICAL CONDITIONS IN POSTMENOPAUSAL WOMEN

OBJECTIVE

The aim: To analyze the available literature on the most common daily urological problems in menopausal women and to evaluate the use of hormone replacement therapy for troublesome urological symptoms.

PATIENTS AND METHODS

Materials and methods: Analysis of publications from PubMed databases on the most common disorders during menopause was performed and the most common urog¬ynaecological problems in postmenopausal women were selected according to literature data. Different available methods of treatment of these disorders were compared. Conclusions: During menopause, women struggle with many unpleasant symptoms from the genitourinary system. For most women, this is a very embarrassing topic and, although bothersome, underestimated. The urinary tract infections, urinary incontinence or kidney stones can lead to serious complications, if left untreated. We should strive to make women more aware of possible methods of prevention and treatment of the menopausal symptoms in the context of urological disorders.

Bladder Exposure to Gardnerella Activates Host Pathways Necessary for Escherichia coli Recurrent UTI

Recurrent urinary tract infections (rUTI) are a costly clinical problem affecting millions of women worldwide each year. The majority of rUTI cases are caused by uropathogenic Escherichia coli (UPEC). Data from humans and mouse models indicate that some instances of rUTI are caused by UPEC emerging from latent reservoirs in the bladder. Women with vaginal dysbiosis, typically characterized by high levels of Gardnerella and other anaerobes, are at increased risk of UTI. Multiple studies have detected Gardnerella in urine collected by transurethral catheterization (to limit vaginal contamination), suggesting that some women experience routine urinary tract exposures. We recently reported that inoculation of Gardnerella into the bladder triggers rUTI from UPEC bladder reservoirs in a mouse model. Here we performed whole bladder RNA-seq to identify host pathways involved in Gardnerella-induced rUTI. We identified a variety host pathways differentially expressed in whole bladders following Gardnerella exposure, such as pathways involved in inflammation/immunity and epithelial turnover. At the gene level, we identified upregulation of Immediate Early (IE) genes, which are induced in various cell types shortly following stimuli like infection and inflammation. One such upregulated IE gene was the orphan nuclear receptor Nur77 (aka Nr4a1). Pilot experiments in Nur77-/- mice suggest that Nur77 is necessary for Gardnerella exposure to trigger rUTI from UPEC reservoirs. These findings demonstrate that bladder gene expression can be impacted by short-lived exposures to urogenital bacteria and warrant future examination of responses in distinct cell types, such as with single cell transcriptomic technologies. The biological validation studies in Nur77-/- mice lay the groundwork for future studies investigating Nur77 and the Immediate Early response in rUTI.

Uropathogenic Escherichia coli Shows Antibiotic Tolerance and Growth Heterogeneity in an In Vitro Model of Intracellular Infection

Uropathogenic Escherichia coli (UPEC), the major causative agent of urinary tract infections, can invade different types of host cells. To compare the pharmacodynamic properties of antibiotics against intra- and extracellular UPEC, an in vitro model of intracellular infection was established in J774 mouse macrophages infected by the UPEC strain CFT073. We tested antibiotics commonly prescribed against urinary tract infections (gentamicin, ampicillin, nitrofurantoin, trimethoprim, sulfamethoxazole, and ciprofloxacin) and the investigational fluoroquinolone finafloxacin. The metabolic activity of individual bacteria was assessed by expressing the fluorescent reporter protein TIMERbac within CFT073. Concentration-response experiments revealed that all tested antibiotics were much less effective against intracellular bacteria than extracellular ones. Most antibiotics, except fluoroquinolones, were unable to reach a bactericidal effect intracellularly at clinically achievable concentrations. Ciprofloxacin and finafloxacin killed 99.9% of extracellular bacteria at concentrations around the MIC, while for intracellular bacteria, concentrations more than 100× over the MIC were required to achieve a bactericidal effect. Time-kill curves showed that finafloxacin was more rapidly bactericidal in acidic medium than at neutral pH, while the reverse observation was made for ciprofloxacin. Intracellularly, kill curves showed biphasic kinetics for both fluoroquinolones, suggesting the presence of drug-tolerant subpopulations. Flow cytometry analysis of TIMERbac fluorescence revealed a marked heterogeneity in intracellular growth of individual bacteria, suggesting that the presence of subpopulations reaching a state of metabolic dormancy was the main reason for increased antibiotic tolerance of intracellular UPEC.

The microbiome and host mucosal interactions in urinary tract diseases

The urinary tract consists of the bladder, ureters, and kidneys, and is an essential organ system for filtration and excretion of waste products and maintaining systemic homeostasis. In this capacity, the urinary tract is impacted by its interactions with other mucosal sites, including the genitourinary and gastrointestinal systems. Each of these sites harbors diverse ecosystems of microbes termed the microbiota, that regulates complex interactions with the local and systemic immune system. It remains unclear whether changes in the microbiota and associated metabolites may be a consequence or a driver of urinary tract diseases. Here, we review the current literature, investigating the impact of the microbiota on the urinary tract in homeostasis and disease including urinary stones, acute kidney injury, chronic kidney disease, and urinary tract infection. We propose new avenues for exploration of the urinary microbiome using emerging technology and discuss the potential of microbiome-based medicine for urinary tract conditions.

Recurrent Urinary Tract Infection: A Mystery in Search of Better Model Systems

Urinary tract infections (UTIs) are among the most common infectious diseases worldwide but are significantly understudied. Uropathogenic E. coli (UPEC) accounts for a significant proportion of UTI, but a large number of other species can infect the urinary tract, each of which will have unique host-pathogen interactions with the bladder environment. Given the substantial economic burden of UTI and its increasing antibiotic resistance, there is an urgent need to better understand UTI pathophysiology - especially its tendency to relapse and recur. Most models developed to date use murine infection; few human-relevant models exist. Of these, the majority of in vitro UTI models have utilized cells in static culture, but UTI needs to be studied in the context of the unique aspects of the bladder's biophysical environment (e.g., tissue architecture, urine, fluid flow, and stretch). In this review, we summarize the complexities of recurrent UTI, critically assess current infection models and discuss potential improvements. More advanced human cell-based in vitro models have the potential to enable a better understanding of the etiology of UTI disease and to provide a complementary platform alongside animals for drug screening and the search for better treatments.

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.

Induction of bacterial cystitis in female rabbits by uropathogenic Escherichia coli and the differences between the bladder dome and trigone

This study is designed to evaluate the histological effects of uropathogenic Escherichia coli (UPEC) infection in the urinary bladder of female rabbits and compare the differences between the dome and trigone. Bacterial cystitis was induced in 13 female rabbits by transurethral inoculation of UPEC into the urinary bladder. Eight animals served as controls. Urine samples were collected by catheterization and cultured for bacterial growth after 12 and 24 hours then every 48 hours. Infection was defined as ≥(1X10⁵) colony-forming unit/ml of UPEC in the first two urine samples. Bladder dome and trigonal specimens were examined by light and scanning electron microscopy eight days after infection. There was a sustained increase in bacterial count, with urethral bleeding and rabbit weakness suggesting bladder colonization in the 10/13 study group (77%). Infection was not demonstrated in two animals and was spontaneously cleared in the third after 48 hours. No control animals developed an infection. In infected rabbits (n = 10), the dome showed inflammatory changes including the epithelial loss or thinning, inflammatory cell infiltration, and congested blood vessels compared to controls. The trigone showed a more pronounced inflammatory response than the dome. The presence of urinary bacterial growth, infection manifestations, and inflammatory changes that were more severe in the trigone than in the dome indicate successful bacterial inoculation and induction of cystitis. This animal model can be used for clinical trials on female cystitis. Our histological findings support a possible role of trigone in the pathogenesis of urinary tract infection.

Interstitial cystitis/bladder pain syndrome and recurrent urinary tract infection and the potential role of the urinary microbiome

Interstitial cystitis/bladder pain syndrome and recurrent urinary tract infections carry significant burden for those affected. As women enter the menopause, other factors may influence how these conditions manifest. The urinary microbiome has shown that the urine contains extensive numbers of bacteria. There is some evidence to suggest that it is altered depending on the menopausal state of the individual. It is possible that this alteration may go on to influence how the disease course of interstitial cystitis/bladder pain syndrome and recurrent urinary tract infections runs in the post-menopausal group. The review will explore these two conditions and the potential role of the urinary microbiome.

Urinary prostaglandin E2 as a biomarker for recurrent UTI in postmenopausal women

This work uses controlled human cohorts to investigate urinary prostaglandin E2, the product of cyclooxygenase-2, as both a diagnostic and prognostic biomarker of recurrent UTI postmenopausal women.

Urinary tract infection (UTI) is one of the most common adult bacterial infections and exhibits high recurrence rates, especially in postmenopausal women. Studies in mouse models suggest that cyclooxygenase-2 (COX-2)–mediated inflammation sensitizes the bladder to recurrent UTI (rUTI). However, COX-2–mediated inflammation has not been robustly studied in human rUTI. We used human cohorts to assess urothelial COX-2 production and evaluate its product, PGE₂, as a biomarker for rUTI in postmenopausal women. We found that the percentage of COX-2–positive cells was elevated in inflamed versus uninflamed bladder regions. We analyzed the performance of urinary PGE₂ as a biomarker for rUTI in a controlled cohort of 92 postmenopausal women and PGE₂ consistently outperformed all other tested clinical variables as a predictor of rUTI status. Furthermore, time-to-relapse analysis indicated that the risk of rUTI relapse was 3.6 times higher in women with above median urinary PGE₂ levels than with below median levels. Taken together, these data suggest that urinary PGE₂ may be a clinically useful diagnostic and prognostic biomarker for rUTI in postmenopausal women.

Complete Genome Sequences of Three Uropathogenic Klebsiella quasipneumoniae Strains Isolated from Postmenopausal Women with Recurrent Urinary Tract Infection

Recurrent urinary tract infection (rUTI) poses a major health issue, especially among postmenopausal women. We report complete genome sequences of three Klebsiella quasipneumoniae strains isolated from the urine of postmenopausal women with rUTI. K. quasipneumoniae is a recently identified Klebsiella species with clinical and virulence characteristics distinct from K. pneumoniae.

Recurrent urinary tract infection (rUTI) poses a major health issue, especially among postmenopausal women. We report complete genome sequences of three Klebsiella quasipneumoniae strains isolated from the urine of postmenopausal women with rUTI. K. quasipneumoniae is a recently identified Klebsiella species with clinical and virulence characteristics distinct from those of K. pneumoniae.

Ciprofloxacin Pharmacokinetics/Pharmacodynamics against Susceptible and Low-Level Resistant Escherichia coli Isolates in an Experimental Ascending Urinary Tract Infection Model in Mice

The mouse ascending urinary tract infection model was used to study the pharmacokinetic/pharmacodynamic (PKPD) relationships of the effect of ciprofloxacin in subcutaneous treatment for 3 days with varying doses and dosing intervals against a susceptible Escherichia coli strain (MIC, 0.032 mg/liter). Further, a humanized dose of ciprofloxacin was administered for 3 days against three E. coli strains with low-level resistance, i.e., MICs of 0.06, 0.25, and 1 mg/liter, respectively. Against the susceptible isolate, ciprofloxacin was highly effective in clearing the urine with daily doses from 10 mg/kg, but the dosing regimen had to be divided into at least two doses for optimal effect. Ciprofloxacin could not clear the urine or kidneys for the low-level-resistant strains. PKPD correlations with all strains combined showed that for the AUC₂₄/MIC there was a slightly higher correlation with effect in urine and kidneys (R ², 0.71 and 0.69, respectively) than the %T_>MIC (R ², 0.41 and 0.61, respectively). Equal correlations for the two PKPD indices were found for reduction of colony counts (CFU) in the bladder tissue, but not even the highest dose of 28 mg/kg × 6 could clear the bladder tissue. In conclusion, ciprofloxacin is highly effective in clearing the urine and kidney tissue for fully susceptible E. coli, while even low-level resistance in E. coli obscures this effect. While the effect of ciprofloxacin is mostly AUC/MIC driven against E. coli infection in the urinary tract, the effect in urine depends on the presence of ciprofloxacin in the urine during most of a 24-h period.

Safety and immunogenicity of an adjuvanted Escherichia coli adhesin vaccine in healthy women with and without histories of recurrent urinary tract infections: results from a first-in-human phase 1 study

Antibiotic resistance among gram-negative bacteria continues to rise globally at an alarming rate. New vaccines that prevent bacterial infections and reduce antibiotic use could provide a potential solution to these problems. This study focused on development of an investigational vaccine to prevent recurrent urinary traction infections (UTI) caused by gram-negative bacteria that use type 1 pili to adhere to, invade, and colonize human bladders. The vaccine antigen is FimH, an adhesin protein on the tip of type 1 pili with a lectin binding domain that enables attachment to glycoproteins on mammalian bladders. This was a phase 1, open-label, dose escalation study evaluating the vaccine in 67 healthy women with and without histories of recurrent UTI. The objectives of the study were to evaluate the safety, tolerability, and immunogenicity of different dosages of the antigen and adjuvant of the vaccine. All dosages were well-tolerated and a low incidence of systemic reactions occurred. No serious adverse events related to the vaccine were reported. The vaccine induced both binding and functional antibodies. The women with histories of recurrent UTI demonstrated greater than 150-fold increases in antibodies against the N-terminal region of FimH. Based on the results of this phase 1 study, this vaccine is proceeding to a double-blind, randomized, placebo-controlled phase 2 study. If this vaccine is successful in future studies, it could potentially prevent millions of recurrent UTI globally and reduce the development of antibiotic resistance.