Inhibition of Cyclooxygenase-2 Prevents Chronic and Recurrent Cystitis

ILC2-derived CGRP triggers acute inflammation and nociceptive responses in bacterial cystitis

Calcitonin gene-related peptide (CGRP), a neuropeptide involved in nociceptor neuronal function, plays a critical role in mediating neuroinflammation and pain. In this study, we find that bladder group 2 innate lymphoid cells (ILC2s) function as primary producers of CGRP in the early phase of bacterial cystitis, contributing to increased inflammation, altered voiding behavior, and heightened pelvic allodynia. Furthermore, we demonstrate that interleukin (IL)-33, a cytokine secreted by urothelial cells, upregulates CGRP production by ILC2s in the bladder during uropathogenic Escherichia coli (UPEC) infection. Moreover, our research reveals that monocytes expressing high levels of receptor activity-modifying protein 1 (RAMP1), a CGRP receptor, mediate the pro-inflammatory effects of CGRP-producing ILC2s. In summary, our results underscore the significance of the immune cell-derived neuropeptides in the pathology of UPEC infection, suggesting a promising therapeutic approach targeting the IL-33-ILC2-CGRP axis for managing lower urinary tract symptoms in bacterial cystitis.

Beneficial Effects Induced by a Proprietary Blend of a New Bromelain-Based Polyenzymatic Complex Plus N-Acetylcysteine in Urinary Tract Infections: Results from In Vitro and Ex Vivo Studies

Background/Objectives: Urinary tract infections (UTIs) are infections that involve the urethra, bladder, and, in much more severe cases, even kidneys. These infections represent one of the most common diseases worldwide. Various pathogens are responsible for this condition, the most common being Escherichia coli (E. coli). Bromelain is a proteolytic complex obtained from the stem and stalk of Ananas comosus (L.) Merr. showing several beneficial activities. In addition to bromelain, N-acetylcysteine (NAC) has also been used. Methods: The purpose of this experiment was to evaluate the antibacterial, anti-motility, and anti-biofilm effects of a new polyenzymatic complex (DIF17BRO®) in combination with NAC (the Formulation) on various strains of E. coli isolated from patients with UTIs. Subsequently, the anti-inflammatory and antioxidant effects of the Formulation were studied in an ex vivo model of cystitis, using bladder samples from mice exposed to E. coli lipopolysaccharide (LPS). Results: Our results showed that the Formulation significantly affects the capability of bacteria to form biofilm and reduces the bacteria amount in the mature biofilm. Moreover, it combines the interesting properties of NAC and a polyenzyme plant complex based on bromelain in a right dose to affect the E. coli adhesion capability. Finally, the Formulation exhibited protective effects, as confirmed by the inhibitory activities on multiple inflammatory and oxidative stress-related pathways on bladder specimens exposed to LPS. Conclusions: This blend of active compounds could represent a promising and versatile approach to use to overcome the limitations associated with conventional therapies.

Fosaprepitant improves cyclophosphamide-induced bladder damage by alleviating inflammatory response in mice

Inhibition of inflammatory process is a key therapeutic target for the treatment of interstitial cystitis (IC). Recent reports indicate that neurokinin 1 receptor (NK1R) antagonists have beneficial roles in inflammatory-based diseases. Herein, we investigate the protective effects of fosaprepitant (FOS), a NK1R antagonist, in cyclophosphamide (CP)-induced cystitis. The cystitis model was established multiple CP (80 mg/kg; i.p.) injection one day apart, and mice were treated with FOS (20 and 60 mg/kg/day; i.p.) for seven consecutive days. Detrusor contractility, vesical vascular permeability, myeloperoxidase (MPO) activity and protein expression levels of the TLR4 pathway were evaluated in mice bladder. Carbachol and electric field stimulation-evoked contractions of detrusor strips were significantly increased in CP-treated mice, which was significantly attenuated by FOS (60 mg/kg/day) treatment (p<0.001, p<0.05). Notably, vesical vascular permeability was markedly impaired in CP-induced cystitis, that was restored by FOS (60 mg/kg/day) treatment (p<0.01). MPO activity was significantly increased in cystitis group whereas FOS (20 and 60 mg/kg/day) treatment remarkably suppressed MPO activity in bladder tissue (p<0.001). Although TLR4 expression increased with cystitis, MyD88 and p-NFκBSer536/total NFκB did not change, FOS (20 and 60 mg/kg/day) treatment caused a dramatic decrease in TLR4 expression (p<0.001), indicating the anti-inflammatory effect of FOS. In conclusion, FOS improved detrusor overactivity and inflammatory response by inhibiting MPO activity and TLR4 expression, resulting in functional and histological recovery in CP-induced cystitis.

Urinary tract infections: pathogenesis, host susceptibility and emerging therapeutics

Urinary tract infections (UTIs), which include any infection of the urethra, bladder or kidneys, account for an estimated 400 million infections and billions of dollars in health-care spending per year. The most common bacterium implicated in UTI is uropathogenic Escherichia coli, but diverse pathogens including Klebsiella, Enterococcus, Pseudomonas, Staphylococcus and even yeast such as Candida species can also cause UTIs. UTIs occur in both women and men and in both healthy and immunocompromised patients. However, certain patient factors predispose to disease: for example, female sex, history of prior UTI, or the presence of a urinary catheter or other urinary tract abnormality. The current clinical paradigm for the treatment of UTIs involves the use of antibiotics. Unfortunately, the efficacy of this approach is dwindling as the prevalence of antimicrobial resistance rises among UTI isolates, and the immense quantity of antibiotics prescribed annually for these infections contributes to the emergence of resistant pathogens. Therefore, there is an urgent need for new antibiotics and non-antibiotic treatment and prevention strategies. In this Review, we discuss how recent studies of bacterial pathogenesis, recurrence, persistence, host-pathogen interactions and host susceptibility factors have elucidated new and promising targets for the treatment and prevention of UTIs.

Current and emerging strategies to curb antibiotic-resistant urinary tract infections

Rising rates of antibiotic resistance in uropathogenic bacteria compromise patient outcomes and prolong hospital stays. Consequently, new strategies are needed to prevent and control the spread of antibiotic resistance in uropathogenic bacteria. Over the past two decades, sizeable clinical efforts and research advances have changed urinary tract infection (UTI) treatment and prevention strategies to conserve antibiotic use. The emergence of antimicrobial stewardship, policies from national societies, and the development of new antimicrobials have shaped modern UTI practices. Future UTI management practices could be driven by the evolution of antimicrobial stewardship, improved and readily available diagnostics, and an improved understanding of how the microbiome affects UTI. Forthcoming UTI treatment and prevention strategies could employ novel bactericidal compounds, combinations of new and classic antimicrobials that enhance bacterial killing, medications that prevent bacterial attachment to uroepithelial cells, repurposing drugs, and vaccines to curtail the rising rates of antibiotic resistance in uropathogenic bacteria and improve outcomes in people with UTI.

Mapping niche-specific two-component system requirements in uropathogenic Escherichia coli

Sensory systems allow pathogens to differentiate between different niches and respond to stimuli within them. A major mechanism through which bacteria sense and respond to stimuli in their surroundings is two-component systems (TCSs). TCSs allow for the detection of multiple stimuli to lead to a highly controlled and rapid change in gene expression. Here, we provide a comprehensive list of TCSs important for the pathogenesis of uropathogenic Escherichia coli (UPEC). UPEC accounts for >75% of urinary tract infections (UTIs) worldwide. UTIs are most prevalent among people assigned female at birth, with the vagina becoming colonized by UPEC in addition to the gut and the bladder. In the bladder, adherence to the urothelium triggers E. coli invasion of bladder cells and an intracellular pathogenic cascade. Intracellular E. coli are safely hidden from host neutrophils, competition from the microbiota, and antibiotics that kill extracellular E. coli. To survive in these intimately connected, yet physiologically diverse niches E. coli must rapidly coordinate metabolic and virulence systems in response to the distinct stimuli encountered in each environment. We hypothesized that specific TCSs allow UPEC to sense these diverse environments encountered during infection with built-in redundant safeguards. Here, we created a library of isogenic TCS deletion mutants that we leveraged to map distinct TCS contributions to infection. We identify-for the first time-a comprehensive panel of UPEC TCSs that are critical for infection of the genitourinary tract and report that the TCSs mediating colonization of the bladder, kidneys, or vagina are distinct.IMPORTANCEWhile two-component system (TCS) signaling has been investigated at depth in model strains of Escherichia coli, there have been no studies to elucidate-at a systems level-which TCSs are important during infection by pathogenic Escherichia coli. Here, we report the generation of a markerless TCS deletion library in a uropathogenic E. coli (UPEC) isolate that can be leveraged for dissecting the role of TCS signaling in different aspects of pathogenesis. We use this library to demonstrate, for the first time in UPEC, that niche-specific colonization is guided by distinct TCS groups.

The Critical Role of Intracellular Bacterial Communities in Uncomplicated Recurrent Urinary Cystitis: A Comprehensive Review of Detection Methods and Diagnostic Potential

Urinary tract infections (UTIs) are among the most common bacterial infections worldwide and are particularly prevalent in women. Recurrent UTIs significantly diminish quality of life due to their symptoms and frequent relapses. Patients often experience immediate relapse following slightly strenuous activities or intense psychological stress. In this review, we explore why infections persist despite the advent of various treatments and suggest strategies to manage recurrent cystitis by targeting the mechanisms of adhesion and infection. Vitamin D levels and the expression of neutrophil gelatinase-associated lipocalin are linked to the recurrence of UTIs. During a UTI, bacteria employ adhesins to invade the urinary tract, adhere to urothelial cells, and then penetrate these cells, where they rapidly multiply to establish intracellular bacterial communities. Bacteria can also form quiescent intracellular reservoirs that escape immune responses and antibiotic treatments, leading to recurrence under certain conditions. The surface proteins of bacteria and D-mannose are crucial in the adhesion of bacteria to the urothelium. Understanding these processes provides valuable insights into potential therapeutic approaches that focus on preventing bacterial attachment and cluster formation. By disrupting the ability of bacteria to adhere to and form clusters on cells, we can better manage recurrent UTIs and improve patient outcomes.

Secretory leukocyte protease inhibitor protects against severe urinary tract infection in mice

Millions suffer from urinary tract infections (UTIs) worldwide every year with women accounting for the majority of cases. Uropathogenic Escherichia coli (UPEC) causes most of these primary infections and leads to 25% becoming recurrent or chronic. To repel invading pathogens, the urinary tract mounts a vigorous innate immune response that includes the secretion of antimicrobial peptides (AMPs), rapid recruitment of phagocytes, and exfoliation of superficial umbrella cells. Here, we investigate secretory leukocyte protease inhibitor (SLPI), an AMP with antiprotease, antimicrobial, and immunomodulatory functions, known to play protective roles at other mucosal sites, but not well characterized in UTIs. Using a preclinical model of UPEC-caused UTI, we show that urine SLPI increases in infected mice and that SLPI is localized to bladder epithelial cells. UPEC-infected SLPI-deficient (Slpi-/-) mice suffer from higher urine bacterial burdens, prolonged bladder inflammation, and elevated urine neutrophil elastase (NE) levels compared to wild-type (Slpi+/+) controls. Combined with bulk bladder RNA sequencing, our data indicate that Slpi-/- mice have a dysregulated immune and tissue repair response following UTI. We also measure SLPI in urine samples from a small group of female subjects 18-49 years old and find that SLPI tends to be higher in the presence of a uropathogen, except in patients with a history of recent or recurrent UTI, suggesting a dysregulation of SLPI expression in these women. Taken together, our findings show SLPI promotes clearance of UPEC in mice and provides preliminary evidence that SLPI is likewise regulated in response to uropathogen exposure in women.IMPORTANCEAnnually, millions of people suffer from urinary tract infections (UTIs) and more than $3 billion are spent on work absences and treatment of these patients. While the early response to UTI is known to be important in combating urinary pathogens, knowledge of host factors that help curb infection is still limited. Here, we use a preclinical model of UTI to study secretory leukocyte protease inhibitor (SLPI), an antimicrobial protein, to determine how it protects the bladder against infection. We find that SLPI is increased during UTI, accelerates the clearance of bacteriuria, and upregulates genes and pathways needed to fight an infection while preventing prolonged bladder inflammation. In a small clinical study, we show SLPI is readily detectable in human urine and is associated with the presence of a uropathogen in patients without a previous history of UTI, suggesting SLPI may play an important role in protecting from bacterial cystitis.

Tamm-Horsfall protein augments neutrophil NETosis during urinary tract infection

Urinary neutrophils are a hallmark of urinary tract infection (UTI), yet the mechanisms governing their activation, function, and efficacy in controlling infection remain incompletely understood. Tamm-Horsfall glycoprotein (THP), the most abundant protein in urine, uses terminal sialic acids to bind an inhibitory receptor and dampen neutrophil inflammatory responses. We hypothesized that neutrophil modulation is an integral part of THP-mediated host protection. In a UTI model, THP-deficient mice showed elevated urinary tract bacterial burdens, increased neutrophil recruitment, and more severe tissue histopathological changes compared to WT mice. Furthermore, THP-deficient mice displayed impaired urinary NETosis during UTI. To investigate the impact of THP on NETosis, we coupled in vitro fluorescence-based NET assays, proteomic analyses, and standard and imaging flow cytometry with peripheral human neutrophils. We found that THP increases proteins involved in respiratory chain, neutrophil granules, and chromatin remodeling pathways, enhances NETosis in an ROS-dependent manner, and drives NET-associated morphologic features including nuclear decondensation. These effects were observed only in the presence of a NETosis stimulus and could not be solely replicated with equivalent levels of sialic acid alone. We conclude that THP is a critical regulator of NETosis in the urinary tract, playing a key role in host defense against UTI.

Exosomes derived from bladder epithelial cells infected with uropathogenic Escherichia coli increase the severity of urinary tract infections (UTIs) by impairing macrophage function

Uropathogenic Escherichia coli (UPEC) is the primary causative agent of urinary tract infections (UTIs) in humans. Moreover, as one of the most common bacterial pathogens, UPEC imposes a substantial burden on healthcare systems worldwide. Epithelial cells and macrophages are two major components of the innate immune system, which play critical roles in defending the bladder against UPEC invasion. Yet, the routes of communication between these cells during UTI pathogenesis are still not fully understood. In the present study, we investigated the role of membrane-bound nanovesicles (exosomes) in the communication between bladder epithelial cells and macrophages during UPEC infection, using an array of techniques such as flow cytometry, miRNA profiling, RNA sequencing, and western blotting. Moreover, our in vitro findings were validated in a mouse model of UPEC-induced cystitis. We found that UPEC infection induced the bladder epithelial MB49 cell line to secrete large numbers of exosomes (MB49-U-Exo), which were efficiently absorbed by macrophages both in vivo and in vitro. Assimilation of MB49-U-Exo induced macrophages to produce proinflammatory cytokines, including tumor necrosis factor (TNF)α. Exposure of macrophages to MB49-U-Exo reduced their phagocytic activity (by downregulating the expression of phagocytosis-related genes) and increased their rate of apoptosis. Mechanistically, we showed that MB49-U-Exo were enriched in miR-18a-5p, which induced TNFα expression in macrophages by targeting PTEN and activating the MAPK/JNK signaling pathway. Moreover, administration of the exosome secretion inhibitor GW4869 or a TNFα-neutralizing antibody alleviated UPEC-mediated tissue damage in mice with UPEC-induced cystitis by reducing the bacterial burden of the bladder and dampening the associated inflammatory response. Collectively, these findings suggest that MB49-U-Exo regulate macrophage function in a way that exacerbates UPEC-mediated tissue impairment. Thus, targeting exosomal -release or TNFα signaling during UPEC infection may represent promising non-antibiotic strategies for treating UTIs.

Cranberry, but not D-mannose and ibuprofen, prevents against uropathogenic Escherichia coli-induced cell damage and cell death in MDCK cells

Introduction

The main function of the urinary tract is to form an impermeable barrier against urinary solutes and bacteria. However, this barrier can be compromised by urinary tract infections, most commonly caused by uropathogenic Escherichia coli (UPEC). This can result in damage to the epithelial barrier, leading to decreased epithelial thickness, loss of tight junctions, loss of epithelial integrity, and apoptosis. Due to the rise in antimicrobial resistance, there is worldwide interest in exploring non-antibiotic agents as alternative therapy.

Methods

Using the Madin-Darby canine kidney (MDCK) cell line, a widely accepted epithelial cell model for the urinary tract, and the UPEC strain UTI89, this paper aimed to investigate the impact of UPEC on cell integrity, permeability, and barrier functions, and determine whether cranberry, D-mannose and ibuprofen could counteract the effects induced by UPEC. Furthermore, the study examined the protective potential of these agents against UPEC-induced increase in reactive oxygen species (ROS) production and programmed death-ligand 1 (PD-L1) expression.

Results

The results demonstrated that UTI89 caused a marked reduction in cell viability and monolayer integrity. Cranberry (3 mg/mL) was protective against these changes. In addition, cranberry exhibited protective effects against UPEC-induced damage to cell barrier integrity, escalation of oxidative stress, and UPEC/TNFα-triggered PD-L1 expression. However, no effect was observed for D-mannose and ibuprofen in alleviating UPEC-induced cell damage and changes in ROS and PD-L1 levels.

Conclusion

Overall, cranberry, but not D-mannose or ibuprofen, has a protective influence against UPEC associated damage in urinary epithelial cells.

Human Ribonuclease 6 Has a Protective Role during Experimental Urinary Tract Infection

Mounting evidence suggests that antimicrobial peptides and proteins (AMPs) belonging to the RNase A superfamily have a critical role in defending the bladder and kidney from bacterial infection. RNase 6 has been identified as a potent, leukocyte-derived AMP, but its impact on urinary tract infection (UTI) in vivo has not been demonstrated. To test the functional role of human RNase 6, we generated RNASE6 transgenic mice and studied their susceptibility to experimental UTI. In addition, we generated bone marrow-derived macrophages to study the impact of RNase 6 on antimicrobial activity within a cellular context. When subjected to experimental UTI, RNASE6 transgenic mice developed reduced uropathogenic Escherichia coli (UPEC) burden, mucosal injury, and inflammation compared to non-transgenic controls. Monocytes and macrophages were the predominant cellular sources of RNase 6 during UTI, and RNASE6 transgenic macrophages were more proficient at intracellular UPEC killing than non-transgenic controls. Altogether, our findings indicate a protective role for human RNase 6 during experimental UTI.

Secretory Leukocyte Protease Inhibitor Protects Against Severe Urinary Tract Infection in Mice

Millions suffer from urinary tract infections (UTIs) worldwide every year with women accounting for the majority of cases. Uropathogenic Escherichia coli (UPEC) causes most of these primary infections and leads to 25% becoming recurrent or chronic. To repel invading pathogens, the urinary tract mounts a vigorous innate immune response that includes the secretion of antimicrobial peptides (AMPs), rapid recruitment of phagocytes and exfoliation of superficial umbrella cells. Here, we investigate secretory leukocyte protease inhibitor (SLPI), an AMP with antiprotease, antimicrobial and immunomodulatory functions, known to play protective roles at other mucosal sites, but not well characterized in UTIs. Using a mouse model of UPEC-caused UTI, we show that urine SLPI increases in infected mice and that SLPI is localized to bladder epithelial cells. UPEC infected SLPI-deficient (Slpi-/-) mice suffer from higher urine bacterial burdens, prolonged bladder inflammation, and elevated urine neutrophil elastase (NE) levels compared to wild-type (Slpi+/+) controls. Combined with bulk bladder RNA sequencing, our data indicate that Slpi-/- mice have a dysregulated immune and tissue repair response following UTI. We also measure SLPI in urine samples from a small group of female subjects 18-49 years old and find that SLPI tends to be higher in the presence of a uropathogen, except in patients with history of recent or recurrent UTI (rUTI), suggesting a dysregulation of SLPI expression in these women. Taken together, our findings show SLPI protects against acute UTI in mice and provides preliminary evidence that SLPI is likewise regulated in response to uropathogen exposure in women.

Celecoxib-Loaded Cubosomal Nanoparticles as a Therapeutic Approach for Staphylococcus aureus In Vivo Infection

There is a great need for novel approaches to treating bacterial infections, due to the vast dissemination of resistance among pathogenic bacteria. Staphylococcus aureus are ubiquitous Gram-positive pathogenic bacteria and are rapidly acquiring antibiotic resistance. Here, celecoxib was encapsulated into cubosomal nanoparticles, and the particle morphology, size distribution, zeta potential, entrapment efficiency, and celecoxib release were evaluated in vitro. Also, a systemic infection model in mice elucidated the in vivo antibacterial action of the celecoxib cubosomes. Cubosomes are a nanotechnology-based delivery system which can adhere to the external peptidoglycan layers of Gram-positive bacteria and penetrate them. The size distribution investigation revealed that the prepared celecoxib-loaded cubosomes had a mean particle size of 128.15 ± 3.04 nm with a low polydispersity index of 0.235 ± 0.023. The zeta potential measurement showed that the prepared cubosomes had a negative surface charge of -17.50 ± 0.45, indicating a highly stable nanodispersion formation with little susceptibility to particle aggregation. The cubosomal dispersion exhibited an entrapment efficiency of 88.57 ± 2.36%. The transmission electron micrograph for the prepared celecoxib-loaded cubosomes showed a narrow size distribution for the cubosomal nanoparticles, which had a spherical shape and were non-aggregated. The tested cubosomes diminished the inflammation in the treated mice's liver and spleen tissues, as revealed by hematoxylin and eosin stain and Masson's trichrome stain. The immunostained tissues with nuclear factor kappa B and caspase-3 monoclonal antibodies revealed a marked decrease in these markers in the celecoxib-treated group, as it resulted in negative or weak immunostaining in liver and spleen that ranged from 4.54% to 17.43%. This indicates their inhibitory effect on the inflammatory pathway and apoptosis, respectively. Furthermore, they reduced the bacterial burden in the studied tissues. This is alongside a decrease in the inflammatory markers (interleukin-1 beta, interleukin-6, cyclooxygenase-2, and tumor necrosis factor-alpha) determined by ELISA and qRT-PCR. The IL-1β levels were 16.66 ± 0.5 pg/mg and 17 ± 0.9 pg/mg in liver and spleen, respectively. Also, IL-6 levels were 85 ± 3.2 pg/mg and 84 ± 2.4 pg/mg in liver and spleen, respectively. In conclusion, the current study introduced cubosomes as an approach for the formulation of celecoxib to enhance its in vivo antibacterial action by improving its oral bioavailability.

Phytotherapy (BNO 1045) of Acute Lower Uncomplicated Urinary Tract Infection in Women Normalizes Local Host Responses

INTRODUCTION

Acute lower uncomplicated urinary tract infection (uUTI) affects a large proportion of women. Increased antimicrobial resistance has created an urgent need for novel therapeutics and the phytotherapeutic drug BNO 1045 (Canephron® N) has previously been shown to be noninferior to standard antimicrobial stewardship. This sub-analysis from a randomized, double-blind, controlled phase III noninferiority clinical trial using BNO 1045 versus fosfomycin to treat uUTI aimed to determine how urine cytokine levels are altered by the two different treatments.

METHODS

Urine samples from a predefined subset of women diagnosed with uUTI (18-70 years) and treated with BNO 1045 (n = 58) or fosfomycin (n = 69) were analyzed for urine levels of IL-6 and IL-8, using analyte-to-creatinine ratios.

RESULTS

BNO 1045 treatment showed similar effects to fosfomycin treatment in reducing both urine IL-6 and IL-8 levels. Mean IL-6 and IL-8 levels were markedly reduced in all patients regardless of treatment. BNO 1045 treatment decreased urine IL-8 significantly (p = 0.0142) and showed a trend toward reduction of urine IL-6 (p = 0.0551). Fosfomycin treatment reduced both IL-6 and IL-8 levels significantly (p = 0.0038, <0.0001 respectively).

CONCLUSION

BNO 1045 is, in addition to reducing symptoms, comparable to fosfomycin treatment in reducing the local inflammatory response associated with uUTI.

Targeting the PRC2-dependent epigenetic program alleviates urinary tract infections

Urinary tract infection (UTI) is a pervasive health problem worldwide. Patients with a history of UTIs suffer increased risk of recurrent infections, a major risk of antibiotic resistance. Here, we show that bladder infections induce expression of Ezh2 in bladder urothelial cells. Ezh2 is the methyltransferase of polycomb repressor complex 2 (PRC2)-a potent epigenetic regulator. Urothelium-specific inactivation of PRC2 results in reduced urine bacterial burden, muted inflammatory response, and decreased activity of the NF-κB signaling pathway. PRC2 inactivation also facilitates proper regeneration after urothelial damage from UTIs, by attenuating basal cell hyperplasia and increasing urothelial differentiation. In addition, treatment with Ezh2-specific small-molecule inhibitors improves outcomes of the chronic and severe bladder infections in mice. These findings collectively suggest that the PRC2-dependent epigenetic reprograming controls the amplitude of inflammation and severity of UTIs and that Ezh2 inhibitors may be a viable non-antibiotic strategy to manage chronic and severe UTIs.

Mapping Niche-specific Two-Component System Requirements in Uropathogenic Escherichia coli

Sensory systems allow pathogens to differentiate between different niches and respond to stimuli within them. A major mechanism through which bacteria sense and respond to stimuli in their surroundings is two-component systems (TCSs). TCSs allow for the detection of multiple stimuli to lead to a highly controlled and rapid change in gene expression. Here, we provide a comprehensive list of TCSs important for the pathogenesis of uropathogenic Escherichia coli (UPEC). UPEC accounts for >75% of urinary tract infections (UTIs) worldwide. UTIs are most prevalent among people assigned female at birth, with the vagina becoming colonized by UPEC in addition to the gut and the bladder. In the bladder, adherence to the urothelium triggers E. coli invasion of bladder cells and an intracellular pathogenic cascade. Intracellular E. coli are safely hidden from host neutrophils, competition from the microbiota, and antibiotics that kill extracellular E. coli. To survive in these intimately connected, yet physiologically diverse niches E. coli must rapidly coordinate metabolic and virulence systems in response to the distinct stimuli encountered in each environment. We hypothesized that specific TCSs allow UPEC to sense these diverse environments encountered during infection with built-in redundant safeguards. Here, we created a library of isogenic TCS deletion mutants that we leveraged to map distinct TCS contributions to infection. We identify - for the first time - a comprehensive panel of UPEC TCSs that are critical for infection of the genitourinary tract and report that the TCSs mediating colonization of the bladder, kidneys, or vagina are distinct.

Uropathogenic Escherichia coli infection-induced epithelial trained immunity impacts urinary tract disease outcome

Previous urinary tract infections (UTIs) can predispose one to future infections; however, the underlying mechanisms affecting recurrence are poorly understood. We previously found that UTIs in mice cause differential bladder epithelial (urothelial) remodelling, depending on disease outcome, that impacts susceptibility to recurrent UTI. Here we compared urothelial stem cell (USC) lines isolated from mice with a history of either resolved or chronic uropathogenic Escherichia coli (UPEC) infection, elucidating evidence of molecular imprinting that involved epigenetic changes, including differences in chromatin accessibility, DNA methylation and histone modification. Epigenetic marks in USCs from chronically infected mice enhanced caspase-1-mediated cell death upon UPEC infection, promoting bacterial clearance. Increased Ptgs2os2 expression also occurred, potentially contributing to sustained cyclooxygenase-2 expression, bladder inflammation and mucosal wounding-responses associated with severe recurrent cystitis. Thus, UPEC infection acts as an epi-mutagen reprogramming the urothelial epigenome, leading to urothelial-intrinsic remodelling and training of the innate response to subsequent infection.

The clinical implications of bacterial pathogenesis and mucosal immunity in chronic urinary tract infection

Urinary tract infections (UTIs) exert a significant health and economic cost globally. Approximately one in four people with a previous history of UTI continue to develop recurrent or chronic infections. Research on UTI has primarily concentrated on pathogen behavior, with the focus gradually shifting to encompass the host immune response. However, these are centered on mouse models of Escherichia coli infection, which may not fully recapitulate the infective etiology and immune responses seen in humans. The emerging field of the urobiome also inadvertently confounds the discrimination of true UTI-causing pathogens from commensals. This review aims to present a novel perspective on chronic UTI by linking microbiology with immunology, which is commonly divergent in this field of research. It also describes the challenges in understanding chronic UTI pathogenesis and the human bladder immune response, largely conjectured from murine studies. Lastly, it outlines the shortcomings of current diagnostic methods in identifying individuals with chronic UTI and consequently treating them, potentially aggravating their disease due to mismanagement of prior episodes. This discourse highlights the need to consider these knowledge gaps and encourages more relevant studies of UTIs in humans.

The immune responses to different Uropathogens call individual interventions for bladder infection

Urinary tract infection (UTI) caused by uropathogens is the most common infectious disease and significantly affects all aspects of the quality of life of the patients. However, uropathogens are increasingly becoming antibiotic-resistant, which threatens the only effective treatment option available-antibiotic, resulting in higher medical costs, prolonged hospital stays, and increased mortality. Currently, people are turning their attention to the immune responses, hoping to find effective immunotherapeutic interventions which can be alternatives to the overuse of antibiotic drugs. Bladder infections are caused by the main nine uropathogens and the bladder executes different immune responses depending on the type of uropathogens. It is essential to understand the immune responses to diverse uropathogens in bladder infection for guiding the design and development of immunotherapeutic interventions. This review firstly sorts out and comparatively analyzes the immune responses to the main nine uropathogens in bladder infection, and summarizes their similarities and differences. Based on these immune responses, we innovatively propose that different microbial bladder infections should adopt corresponding immunomodulatory interventions, and the same immunomodulatory intervention can also be applied to diverse microbial infections if they share the same effective therapeutic targets.

Urinary Tract Infection in Overactive Bladder: An Update on Pathophysiological Mechanisms

Overactive bladder (OAB) is a clinical syndrome defined by urinary urgency, increased daytime urinary frequency and/or nocturia, with or without urinary incontinence, that affects approximately 11% of the western population. OAB is accepted as an idiopathic disorder, and is charactersied clinically in the absence of other organic diseases, including urinary tract infection. Despite this, a growing body of research provides evidence that a significant proportion of OAB patients have active bladder infection. This review discusses the key findings of recent laboratory and clinical studies, providing insight into the relationship between urinary tract infection, bladder inflammation, and the pathophysiology of OAB. We summarise an array of clinical studies that find OAB patients are significantly more likely than control patients to have pathogenic bacteria in their urine and increased bladder inflammation. This review reveals the complex nature of OAB, and highlights key laboratory studies that have begun to unravel how urinary tract infection and bladder inflammation can induce urinary urgency and urinary frequency. The evidence presented in this review supports the concept that urinary tract infection may be an underappreciated contributor to the pathophysiology of some OAB patients.

A Systematic Review of the (Un)known Host Immune Response Biomarkers for Predicting Recurrence of Urinary Tract Infection

Recurrent urinary tract infections (rUTI) represent a major healthcare and economic burden along with a significant impact on patient’s morbidity and quality of life, even in the absence of well-known risk factors, such as vesicoureteral reflux. Despite numerous attempts to find a suitable therapeutic option, there is no clear benefit of any currently available intervention for prevention of UTI recurrence and its long-term consequences such as hypertension, renal scarring and/or insufficiency. The common treatment practice in many centers around the globe involves the use of continuous low-dose antibiotic prophylaxis, irrespective of various studies indicating increased microbial resistance against the prophylactic drug, leading to prolonged duration and escalating the cost of UTI treatment. Moreover, the rapid appearance of multi-drug resistant uropathogens is threatening to transform UTI to untreatable disease, while impaired host-microbiota homeostasis induced by a long-term use of antibiotics predisposes patients for various autoimmune and infectious diseases. New biomarkers of the increased risk of UTI recurrence could therefore assist in avoiding such outcomes by revealing more specific patient population which could benefit from additional interventions. In this light, the recent findings suggesting a crucial role of urothelial innate immunity mechanisms in protection of urinary tract from invading uropathogens might offer new diagnostic, prognostic and even therapeutic opportunities. Uroepithelial cells detect uropathogens via pattern recognition receptors, resulting in activation of intracellular signaling cascade and transcription factors, which ultimately leads to an increased production and secretion of chemokines, cytokines and antimicrobial peptides into the urinary stream. Emerging evidence suggest that the disturbance of a single component of the urinary tract innate immunity system might increase susceptibility for rUTI. The aim of the current review is to update clinicians and researchers on potential biomarkers of host immune response alterations predisposing for rUTI and propose those well worth exploring further. For this purpose, over a hundred original papers were identified through an extensive PubMed and Scopus databases search. This comprehensive review might enrich the current clinical practice and fill the unmet clinical needs, but also encourage the development of therapeutic agents that would facilitate urinary bacterial clearance by enhancing the host immune response.

Experimental in vivo model to evaluate the impact of Cernitin™ on pain response on induced chronic bladder inflammation

OBJECTIVE

Inflammation of the urinary bladder may cause burdensome pain also called bladder pain syndrome (BPS). A limitation in understanding BPS pathophysiology is the lack of appropriate preclinical model. Previously published clinical and preclinical studies revealed positive impact of Cernitin™ on pain relief in chronic prostatitis. The objective of this study was to evaluate the effects of Cernitin™ on induced inflammation of the urinary bladder in rats. We also sought to identify biomarkers which might play a role in the management of BPS.

MATERIALS AND METHODS

Cystitis was induced by injection of cyclophosphamide (CYP) in female rats. Thereafter, animals were randomly divided into four treatment groups and two control groups. Evaluation of pain scores was assessed by von Frey assay. Expression of pain- and pro-inflammatory biomarkers was determined by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry.

RESULTS

Treatments with Cernitin™ displayed significant anti-nociceptive effects on CYP-induced visceral pain (p < .01). In contrast, vehicle-treated animals showed high pain score even at the lowest force. Furthermore, results of ELISA showed that Cernitin™-treated animals had significantly reduced levels of COX-2 (T60, p < .01; GBX, p < .05) in bladder tissue homogenate. Immunohistochemical (IHC) staining of bladder tissues showed that Cernitin™-treated animals exhibited less CD45-positive cells, while massive CD45-positive cells infiltration was detected in vehicle-treated animals. IHC also revealed lower SP and PGD2 expression levels in Cernitin™-treated tissues.

CONCLUSIONS

Cernitin™ components reduced pain score and inflammatory marker COX-2. Our findings suggest a potential therapeutic role for Cernitin™ in the management of BPS.

Immunomodulation therapy offers new molecular strategies to treat UTI

Innovative solutions are needed for the treatment of bacterial infections, and a range of antibacterial molecules have been explored as alternatives to antibiotics. A different approach is to investigate the immune system of the host for new ways of making the antibacterial defence more efficient. However, the immune system has a dual role as protector and cause of disease: in addition to being protective, increasing evidence shows that innate immune responses can become excessive and cause acute symptoms and tissue pathology during infection. This role of innate immunity in disease suggests that the immune system should be targeted therapeutically, to inhibit over-reactivity. The ultimate goal is to develop therapies that selectively attenuate destructive immune response cascades, while augmenting the protective antimicrobial defence but such treatment options have remained underexplored, owing to the molecular proximity of the protective and destructive effects of the immune response. The concept of innate immunomodulation therapy has been developed successfully in urinary tract infections, based on detailed studies of innate immune activation and disease pathogenesis. Effective, disease-specific, immunomodulatory strategies have been developed by targeting specific immune response regulators including key transcription factors. In acute pyelonephritis, targeting interferon regulatory factor 7 using small interfering RNA or treatment with antimicrobial peptide cathelicidin was protective and, in acute cystitis, targeting overactive effector molecules such as IL-1β, MMP7, COX2, cAMP and the pain-sensing receptor NK1R has been successful in vivo. Furthermore, other UTI treatment strategies, such as inhibiting bacterial adhesion and vaccination, have also shown promise.

Hyperactivation of innate immunity is a disease determinant in urinary tract infections (UTIs). Modulation of innate immunity has promise as a therapy for UTIs. In this Review, the authors discuss potential mechanisms and immunomodulatory therapeutic strategies in UTIs.

Excessive innate immune responses to infection cause symptoms and pathology in acute pyelonephritis and acute cystitis.

Innate immunomodulation therapy is, therefore, a realistic option for treating these conditions.

Targeting excessive innate immune responses at the level of transcription has been successful in animal models.

Innate immunomodulation therapy reduces excessive inflammation and tissue pathology and accelerates bacterial clearance from infected kidneys and bladders in mice.

Innate immunomodulation therapy also accelerates the clearance of antibiotic-resistant bacterial strains.

Label-Free, Novel Electrofluidic Capacitor Biosensor for Prostaglandin E2 Detection toward Early and Rapid Urinary Tract Infection Diagnosis

Urine Prostaglandin E2 (PGE2) has been identified as an attractive diagnostic and prognostic biomarker for urinary tract infection (UTI). This work demonstrates the use of PGE2 as a biomarker for rapid and label-free testing for UTI. In this work, we have developed a novel electrofluidic capacitor-based biosensor that can used for home-based UTI management with high accuracy in less than 5 min for small volume urine samples (<60 μL). The PGE2 biosensor works on the principle of affinity capture using highly specific monoclonal PGE2 antibody and relies on non-faradaic electrical impedance spectroscopy (EIS) and Mott-Schottky (MS) for quantifying subtle variations in PGE2 levels expressed in human urine (pH 5-8). Dynamic light scattering experiments were performed to characterize surface charge properties and the impact of bulk interferents on the interfacial modulation of electrical properties due to binding and urine pH variations. Binding chemistry between the key elements of the immunosensor stack was validated using attenuated total reflectance-Fourier transform infrared spectroscopy and surface plasmon resonance studies. Linear calibration dose responses were obtained for PGE2 for both EIS and MS. The sensor reliably distinguished between UTI negative and UTI positive cases for both artificial (pH 5-8) and pooled human urine samples. The sensor was not found to cross-react with Prostaglandin D2, a structurally similar interferent, and other abundant urine interferents (urea and creatinine). Human subject studies confirmed the validity of the sensor for robust and accurate UTI diagnosis. This work can be extended to achieve easy, reliable, and rapid home-based UTI management, which can consequently help physicians with timely and appropriate administration of therapy to improve patient outcomes and treatment success.

Label Free, Lateral Flow Prostaglandin E2 Electrochemical Immunosensor for Urinary Tract Infection Diagnosis

A label-free, rapid, and easy-to-use lateral flow electrochemical biosensor was developed for urinary tract infection (UTI) diagnosis in resource challenged areas. The sensor operates in non-faradaic mode and utilizes Electrochemical Impedance Spectroscopy for quantification of Prostaglandin E2, a diagnostic and prognostic urinary biomarker for UTI and recurrent UTI. To achieve high sensitivity in low microliter volumes of neat, unprocessed urine, nanoconfinement of assay biomolecules was achieved by developing a three-electrode planar gold microelectrode system on top of a lateral flow nanoporous membrane. The sensor is capable of giving readouts within 5 min and has a wide dynamic range of 100–4000 pg/mL for urinary PGE2. The sensor is capable of discriminating between low and high levels of PGE2 and hence is capable of threshold classification of urine samples as UTI positive and UTI negative. The sensor through its immunological response (directly related to host immune response) is superior to the commercially available point-of-care UTI dipsticks which are qualitative, have poor specificity for UTI, and have high false-positive rates. The developed sensor shows promise for rapid, easy and cost-effective UTI diagnosis for both clinical and home-based settings. More accurate point-of-care UTI diagnosis will improve patient outcomes and allow for timely and appropriate prescription of antibiotics which can subsequently increase treatment success rates and reduce costs.

Metabolic acidosis exacerbates pyelonephritis in mice prone to vesicoureteral reflux

Acute pyelonephritis is a common, serious bacterial infection in children. The prevalence of acute pyelonephritis is due at least in part to vesicoureteral reflux (VUR). Although an association between abnormalities in electrolyte and acid–base balance and pyelonephritis is common in young children, the impact of metabolic acidosis (MA) on progression of acute pyelonephritis is not fully understood. In this study, the effect of MA on pyelonephritis was studied in C3H mouse strains prone to VUR. MA induced by ammonium chloride supplementation in food specifically impaired clearance of urinary tract infection with uropathogenic Escherichia. coli (UPEC‐UTI) in innate immune competent C3H strains (HeOuJ, HeN), whereas kidney UPEC burden in Tlr‐4‐deficient HeJ mice was unaffected. Antibody‐mediated depletion of myeloid cells (monocytes, neutrophil) markedly increased UPEC burden in the bladder and kidney confirming the pivotal role of neutrophils and tissue‐resident macrophages in clearance of UPEC‐UTI. MA concurrent with UPEC‐UTI markedly increased expression of cytokine (TNFα, IL‐1β, IL‐6) and chemokine (CXCL 1, 2, and 5) mRNA in isolated kidney CD cells and kidney neutrophil infiltrates were increased four‐ to fivefold compared to normal, UPEC‐infected mice. Thus, MA intensified pyelonephritis and increased the risk of kidney injury by impairing clearance of UPEC‐UTI and potentiating renal inflammation characterized by an elevated kidney neutrophil infiltrate.

Infección de vías urinarias no complicada en mujeres

La infección de vías urinarias (IVU) es una patología común, que afecta a gran parte de la población y que generalmente se resuelve con manejo antibiótico. Se compone de una amplia variedad de entidades clínicas que pueden variar desde una cistitis no complicada hasta un shock séptico de origen urinario. Los patógenos etiológicos de la IVU no complicada están ampliamente establecidos y se han mantenido de forma consistente a lo largo del tiempo, siendo la Escherichia coli el microorganismo más predominante. En la actualidad, la resistencia bacteriana a los antibióticos es de gran preocupación y por esa razón, se busca optimizar la terapia antimicrobiana con el fin de disminuir la estancia hospitalaria, la severidad clínica de la infección y los costos a los sistemas de salud. La presente revisión, tiene como objetivo servir como guía para la correcta definición, clasificación, diagnóstico, tratamiento y prevención de la IVU no complicada.

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.

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.

Urinary cytokines in women with refractory detrusor overactivity: A longitudinal study of rotating antibiotic versus placebo treatment

Over 50% of women with detrusor overactivity (DO), who do not respond to therapy have been shown to have bacteriuria, which may stimulate the release of inflammatory cytokines than can enhance nerve signalling, leading to symptoms of urgency. This study made use of a consecutive series of urine samples collected from women with refractory DO, who participated in a clinical trial of rotating antibiotic therapy. The aim was to determine the effect of bacteriuria and antibiotic treatment on the levels of urinary cytokines, and to correlate the cytokine concentration with patient outcome measures relating to urgency or urge incontinence. The urinary cytokines chosen were IL-1α, IL-1 receptor antagonist, IL-4, IL-6, IL-8, IL-10, CXCL10 (IP-10), MCP-1 and TNF-α. The presence of bacteriuria stimulated a significant increase in the concentrations of IL-1α (P 0.0216), IL-1 receptor antagonist (P 0.0264), IL-6 (P 0.0003), IL-8 (P 0.0043) and CXCL-10 (P 0.009). Antibiotic treatment significantly attenuated the release of IL-1α (P 0.005), IL-6 (P 0.0027), IL-8 (P 0.0001), IL-10 (P 0.049), and CXCL-10 (P 0.042), i.e. the response to the presence of bacteria was less in the antibiotic treated patients. Across the 26 weeks of the trial, antibiotic treatment reduced the concentration of five of the nine cytokines measured (IL-1α, IL-6, IL-8, IL-10 and CXCL-10); this did not reach significance at every time point. In antibiotic treated patients, the urinary concentration of CXCL-10 correlated positively with four of the six measures of urgency. This study has shown that cytokines associated with activation of the innate immune system (e.g. cytokines chemotactic for or activators of macrophages and neutrophils) are reduced by antibiotic therapy in women with refractory DO. Antibiotic therapy is also associated with symptom improvement in these women, therefore the inflammatory response may have a role in the aetiology of refractory DO.

Adaptation of Arginine Synthesis among Uropathogenic Branches of the Escherichia coli Phylogeny Reveals Adjustment to the Urinary Tract Habitat

Uropathogenic Escherichia coli (UPEC) is the most common cause of human urinary tract infection (UTI). Population bottlenecks during early stages of UTI make high-throughput screens impractical for understanding clinically important later stages of UTI, such as persistence and recurrence. As UPEC is hypothesized to be adapted to these later pathogenic stages, we previously identified 29 genes evolving under positive selection in UPEC. Here, we found that 8 of these genes, including argI (which is involved in arginine biosynthesis), are important for persistence in a mouse model of UTI. Deletion of argI and other arginine synthesis genes resulted in (i) arginine auxotrophy and (ii) defects in persistent UTI. Replacement of a B2 clade argI with a non-B2 clade argI complemented arginine auxotrophy, but the resulting strain remained attenuated in its ability to cause persistent bacteriuria. Thus, argI may have a second function during UTI that is not related to simple arginine synthesis. This study demonstrates how variation in metabolic genes can impact virulence and provides insight into the mechanisms and evolution of bacterial virulence.

Urinary tract infections (UTIs) are predominantly caused by uropathogenic Escherichia coli (UPEC). UPEC pathogenesis requires passage through a severe population bottleneck involving intracellular bacterial communities (IBCs) that are clonal expansions of a single invading UPEC bacterium in a urothelial superficial facet cell. IBCs occur only during acute pathogenesis. The bacteria in IBCs form the founder population that develops into persistent extracellular infections. Only a small fraction of UPEC organisms proceed through the IBC cycle, regardless of the inoculum size. This dramatic reduction in population size precludes the utility of genomic mutagenesis technologies for identifying genes important for persistence. To circumvent this bottleneck, we previously identified 29 positively selected genes (PSGs) within UPEC and hypothesized that they contribute to virulence. Here, we show that 8 of these 29 PSGs are required for fitness during persistent bacteriuria. Conversely, 7/8 of these PSG mutants showed essentially no phenotype in acute UTI. Deletion of the PSG argI leads to arginine auxotrophy. Relative to the other arg genes, argI in the B2 clade (which comprises most UPEC strains) of E. coli has diverged from argI in other E. coli clades. Replacement of argI in a UPEC strain with a non-UPEC argI allele complemented the arginine auxotrophy but not the persistent bacteriuria defect, showing that the UPEC argI allele contributes to persistent infection. These results highlight the complex roles of metabolic pathways during infection and demonstrate that evolutionary approaches can identify infection-specific gene functions downstream of population bottlenecks, shedding light on virulence and the genetic evolution of pathogenesis.

Depletion of multidrug-resistant uropathogenic Escherichia coli BC1 by ebselen and silver ion

Ebselen, an organo‐selenium compound with well‐characterized toxicology and pharmacology, recently exhibited potent antibacterial activity against glutathione (GSH)‐negative bacteria by disrupting redox homeostasis. In this paper, we show that ebselen and silver ion in combination exert strong bactericidal activity against multidrug‐resistant (MDR) uropathogenic Escherichia coli (UPEC) BC1, a model MDR GSH‐positive bacterium. The mechanisms were found to involve consumption of total intracellular GSH and inhibition of thioredoxin reductase activity, which was highly related to reactive oxygen species up‐regulation. Furthermore, the therapeutic efficacy of ebselen and silver ion against UPEC‐induced cystitis was assessed in a mouse model. Treatment with ebselen and silver ion significantly reduced bacterial loads, down‐regulated the expression levels of tumour necrosis factor‐α (TNF‐α) and interferon‐γ (IFN‐γ) on‐site and decreased white/red blood cell counts in mild cystitis model mice, which demonstrated the anti‐inflammatory property of these agents. In addition, ebselen and silver ion also exhibited significantly high protective ability (100%) against acute cystitis infections. These results together may lay the foundation for further analysis and development of ebselen and silver ion as antibacterial agents for treatment of MDR UPEC infections.

Restriction of chronic Escherichia coli urinary tract infection depends upon T cell-derived interleukin-17, a deficiency of which predisposes to flagella-driven bacterial persistence

Urinary tract infections (UTI) frequently progress to chronicity in infected individuals but the mechanisms of pathogenesis underlying chronic UTI are not well understood. We examined the role of interleukin (IL)-17A in UTI because this cytokine promotes innate defense against uropathogenic Escherichia coli (UPEC). Analysis of UPEC persistence and pyelonephritis in mice deficient in IL-17A revealed that UPEC CFT073 caused infection at a rate higher than the multidrug resistant strain EC958. Il17a^-/- mice exhibited pyelonephritis with kidney bacterial burdens higher than those of wild-type (WT) mice. Synthesis of IL-17A in the bladder reflected a combination of γδ-T and T_H 17 cell responses. Analysis of circulating inflammatory mediators at 24h postinoculation identified predictors of progression to chronicity, including IL-6 and monocyte chemoattractant protein-1 (MCP-1). Histological analysis identified infiltrating populations of neutrophils, NK cells, and γδ T cells in the bladder, whereas neutrophils predominated in the kidney. Analysis of the contribution of flagella to chronicity using hyper-flagellated and fliC-deficient UPEC in WT and Il17a^-/- mice revealed that, in a host that is deficient for the production of IL-17A, flagella contribute to bacterial persistence. These findings show a role for IL-17A in defense against chronic UTI and a contribution of flagella to the pathogenesis of infection.

The immune response to infection in the bladder

The bladder is continuously protected by passive defences such as a mucus layer, antimicrobial peptides and secretory immunoglobulins; however, these defences are occasionally overcome by invading bacteria that can induce a strong host inflammatory response in the bladder. The urothelium and resident immune cells produce additional defence molecules, cytokines and chemokines, which recruit inflammatory cells to the infected tissue. Resident and recruited immune cells act together to eradicate bacteria from the bladder and to develop lasting immune memory against infection. However, urinary tract infection (UTI) is commonly recurrent, suggesting that the induction of a memory response in the bladder is inadequate to prevent reinfection. Additionally, infection seems to induce long-lasting changes in the urothelium, which can render the tissue more susceptible to future infection. The innate immune response is well-studied in the field of UTI, but considerably less is known about how adaptive immunity develops and how repair mechanisms restore bladder homeostasis following infection. Furthermore, data demonstrate that sex-based differences in immunity affect resolution and infection can lead to tissue remodelling in the bladder following resolution of UTI. To combat the rise in antimicrobial resistance, innovative therapeutic approaches to bladder infection are currently in development. Improving our understanding of how the bladder responds to infection will support the development of improved treatments for UTI, particularly for those at risk of recurrent infection.

Alternative Therapeutic Options to Antibiotics for the Treatment of Urinary Tract Infections

Urinary tract infections (UTIs) mainly caused by Uropathogenic Escherichia coli (UPEC), are common bacterial infections. Many individuals suffer from chronically recurring UTIs, sometimes requiring long-term prophylactic antibiotic regimens. The global emergence of multi-drug resistant uropathogens in the last decade underlines the need for alternative non-antibiotic therapeutic and preventative strategies against UTIs. The research on non-antibiotic therapeutic options in UTIs has focused on the following phases of the pathogenesis: colonization, adherence of pathogens to uroepithelial cell receptors and invasion. In this review, we discuss vaccines, small compounds, nutraceuticals, immunomodulating agents, probiotics and bacteriophages, highlighting the challenges each of these approaches face. Most of these treatments show interesting but only preliminary results. Lactobacillus-containing products and cranberry products in conjunction with propolis have shown the most robust results to date and appear to be the most promising new alternative to currently used antibiotics. Larger efficacy clinical trials as well as studies on the interplay between non-antibiotic therapies, uropathogens and the host immune system are warranted.

Innate immunity and urinary tract infection

Urinary tract infections are a severe public health problem. The emergence and spread of antimicrobial resistance among uropathogens threaten to further compromise the quality of life and health of people who develop acute and recurrent upper and lower urinary tract infections. The host defense mechanisms that prevent invasive bacterial infection are not entirely delineated. However, recent evidence suggests that versatile innate immune defenses play a key role in shielding the urinary tract from invading uropathogens. Over the last decade, considerable advances have been made in defining the innate mechanisms that maintain immune homeostasis in the kidney and urinary tract. When these innate defenses are compromised or dysregulated, pathogen susceptibility increases. The objective of this review is to provide an overview of how basic science discoveries are elucidating essential innate host defenses in the kidney and urinary tract. In doing so, we highlight how these findings may ultimately translate into the clinic as new biomarkers or therapies for urinary tract infection.

Host Cathelicidin Exacerbates Group B Streptococcus Urinary Tract Infection

Group B Streptococcus (GBS) causes frequent urinary tract infection (UTI) in susceptible populations, including individuals with type 2 diabetes and pregnant women; however, specific host factors responsible for increased GBS susceptibility in these populations are not well characterized. Here, we investigate cathelicidin, a cationic antimicrobial peptide, known to be critical for defense during UTI with uropathogenic Escherichia coli (UPEC). We observed a loss of antimicrobial activity of human and mouse cathelicidins against GBS and UPEC in synthetic urine and no evidence for increased cathelicidin resistance in GBS urinary isolates. Furthermore, we found that GBS degrades cathelicidin in a protease-dependent manner. Surprisingly, in a UTI model, cathelicidin-deficient (Camp-/-) mice showed decreased GBS burdens and mast cell recruitment in the bladder compared to levels in wild-type (WT) mice. Pharmacologic inhibition of mast cells reduced GBS burdens and histamine release in WT but not Camp-/- mice. Streptozotocin-induced diabetic mice had increased bladder cathelicidin production and mast cell recruitment at 24 h postinfection with GBS compared to levels in nondiabetic controls. We propose that cathelicidin is an important immune regulator but ineffective antimicrobial peptide against GBS in urine. Combined, our findings may in part explain the increased frequency of GBS UTI in diabetic and pregnant individuals.IMPORTANCE Certain populations such as diabetic individuals are at increased risk for developing urinary tract infections (UTI), although the underlying reasons for this susceptibility are not fully known. Additionally, diabetics are more likely to become infected with certain types of bacteria, such as group B Streptococcus (GBS). In this study, we find that an antimicrobial peptide called cathelicidin, which is thought to protect the bladder from infection, is ineffective in controlling GBS and alters the type of immune cells that migrate to the bladder during infection. Using a mouse model of diabetes, we observe that diabetic mice are more susceptible to GBS infection even though they also have more infiltrating immune cells and increased production of cathelicidin. Taken together, our findings identify this antimicrobial peptide as a potential contributor to increased susceptibility of diabetic individuals to GBS UTI.

Cyclooxygenase-2 Inhibition Reduces Autophagy of Macrophages Enhancing Extraintestinal Pathogenic Escherichia coli Infection

Extraintestinal pathogenic Escherichia coli (ExPEC) is one of the top pathogens responsible for bloodstream infection and severe, often fatal, sepsis. Although the virulence factors and host immune responses to ExPEC infection have been investigated, the responses to a particular ExPEC strain could be very different. In this study, we investigated the mechanisms of Cyclooxygenase-2 (COX-2) up-regulation in influencing the host defenses against infection of ExPEC XM O2:K1:H7. Our results demonstrated that ExPEC XM O2:K1:H7 infection in mouse and RAW264.7 macrophages leads to COX-2 up-regulation, and COX-2 inhibition significantly enhances ExPEC infection. The up-regulation of COX-2 in macrophages was mediated by Toll-like receptor 4 (TLR4) through the activation of p38 and extracellular signal-regulated kinase/Mitogen-activated protein kinase (ERK/MAPK) pathways. Further studies showed that COX-2 inhibition significantly decreased autophagy in macrophages during ExPEC XM O2:K1:H7 infection. Autophagy inhibition significantly enhanced, while induction reduced ExPEC XM O2:K1:H7 survival in macrophages. In addition, COX-2 inhibition significantly increased macrophage cell death during ExPEC XM O2:K1:H7 infection and increased the expression of anti-inflammatory cytokine interleukin-10 (IL-10). Our results indicate that COX-2 up-regulation benefits host defense against ExPEC XM O2:K1:H7 infection by increasing autophagy in macrophages and by reducing IL-10 expression and macrophage cell death during ExPEC infection.

Urinary tract infections: microbial pathogenesis, host-pathogen interactions and new treatment strategies

Urinary tract infections (UTIs) are common, recurrent infections that can be mild to life-threatening. The continued emergence of antibiotic resistance, together with our increasing understanding of the detrimental effects conferred by broad-spectrum antibiotic use on the health of the beneficial microbiota of the host, has underscored the weaknesses in our current treatment paradigm for UTIs. In this Review, we discuss how recent microbiological, structural, genetic and immunological studies have expanded our understanding of host-pathogen interactions during UTI pathogenesis. These basic scientific findings have the potential to shift the strategy for UTI treatment away from broad-spectrum antibiotics targeting conserved aspects of bacterial replication towards pathogen-specific antibiotic-sparing therapeutics that target core determinants of bacterial virulence at the host-pathogen interface.

Spatial proteomics revealed a CX3CL1-dependent crosstalk between the urothelium and relocated macrophages through IL-6 during an acute bacterial infection in the urinary bladder

The urothelium of the urinary bladder represents the first line of defense. However, uropathogenic E. coli (UPEC) damage the urothelium and cause acute bacterial infection. Here, we demonstrate the crosstalk between macrophages and the urothelium stimulating macrophage migration into the urothelium. Using spatial proteomics by MALDI-MSI and LC-MS/MS, a novel algorithm revealed the spatial activation and migration of macrophages. Analysis of the spatial proteome unravelled the coexpression of Myo9b and F4/80 in the infected urothelium, indicating that macrophages have entered the urothelium upon infection. Immunofluorescence microscopy additionally indicated that intraurothelial macrophages phagocytosed UPEC and eliminated neutrophils. Further analysis of the spatial proteome by MALDI-MSI showed strong expression of IL-6 in the urothelium and local inhibition of this molecule reduced macrophage migration into the urothelium and aggravated the infection. After IL-6 inhibition, the expression of matrix metalloproteinases and chemokines, such as CX₃CL1 was reduced in the urothelium. Accordingly, macrophage migration into the urothelium was diminished in the absence of CX₃CL1 signaling in Cx₃cr1^gfp/gfp mice. Conclusively, this study describes the crosstalk between the infected urothelium and macrophages through IL-6-induced CX₃CL1 expression. Such crosstalk facilitates the relocation of macrophages into the urothelium and reduces bacterial burden in the urinary bladder.

The effect of Seidlitzia rosmarinus (eshnan) on the prevention of recurrent cystitis in women of reproductive age: A randomized, controlled, clinical trial

The World Health Organization has recommended herbal medicine for treatment and control of recurrent cystitis. This study was conducted to determine effect of eshnan on the prevention of recurrent cystitis. The present triple-blind clinical trial was conducted on 126 women (63 women per group) with recurrent cystitis. The participants were assigned to the intervention and control groups. Three 500-mg eshnan or placebo tablets were taken orally with a glass full of water by the participants half an hour after each meal for 2 months. The study subjects were clinically and paraclinically evaluated by the end of the second, fourth, and sixth months after the intervention and every time they showed clinical symptoms of cystitis. The present findings showed that the incidence rate of cystitis and symptoms of cystitis was significantly lower in the eshnan group compared with the placebo group 2, 4, and 6 months after the intervention (p < .05). The incidence of recurrent was also significantly lower in the intervention group compared with the control group (p < .001). No side effects were observed in the intervention and control groups. The consumption of eshnan can improve the symptoms of cystitis and prevent the incidence of recurrent cystitis in women of reproductive age.

Nonantibiotic prevention and management of recurrent urinary tract infection

Urinary tract infections (UTIs) are highly prevalent, lead to considerable patient morbidity, incur large financial costs to health-care systems and are one of the most common reasons for antibiotic use worldwide. The growing problem of antimicrobial resistance means that the search for nonantibiotic alternatives for the treatment and prevention of UTI is of critical importance. Potential nonantibiotic measures and treatments for UTIs include behavioural changes, dietary supplementation (such as Chinese herbal medicines and cranberry products), NSAIDs, probiotics, D-mannose, methenamine hippurate, estrogens, intravesical glycosaminoglycans, immunostimulants, vaccines and inoculation with less-pathogenic bacteria. Some of the results of trials of these approaches are promising; however, high-level evidence is required before firm recommendations for their use can be made. A combination of these agents might provide the optimal treatment to reduce recurrent UTI, and trials in specific population groups are required.

Mucosal infection rewires TNFɑ signaling dynamics to skew susceptibility to recurrence

A mucosal infectious disease episode can render the host either more or less susceptible to recurrent infection, but the specific mechanisms that tip the balance remain unclear. We investigated this question in a mouse model of recurrent urinary tract infection and found that a prior bladder infection resulted in an earlier onset of tumor necrosis factor-alpha (TNFɑ)-mediated bladder inflammation upon subsequent bacterial challenge, relative to age-matched naive mice. However, the duration of TNFɑ signaling activation differed according to whether the first infection was chronic (Sensitized) or self-limiting (Resolved). TNFɑ depletion studies revealed that transient early-phase TNFɑ signaling in Resolved mice promoted clearance of bladder-colonizing bacteria via rapid recruitment of neutrophils and subsequent exfoliation of infected bladder cells. In contrast, sustained TNFɑ signaling in Sensitized mice prolonged damaging inflammation, worsening infection. This work reveals how TNFɑ signaling dynamics can be rewired by a prior infection to shape diverse susceptibilities to future mucosal infections.

Ibuprofen lacks direct antimicrobial properties for the treatment of urinary tract infection isolates

The high incidence of urinary tract infection (UTI) among women and children, in combination with a lack of antibiotic efficacy with regard to pathogen eradication and recurrence prevention, as well as the negative side effects associated with antibiotics, has led researchers to explore the role of non-steroidal anti-inflammatory drugs as a primary management strategy. The aim of this study was to determine whether ibuprofen (IBU) or one of its major metabolites, 2-carboxyibuprofen (CIBU), could affect the growth and adhesion of the two most common uropathogens, Escherichia coli and Enterococcus faecalis. The bacterial growth and adhesion to the urothelial cells of E. coli UTI89 and E. faecalis 1131 in the presence of physiologically relevant concentrations of IBU and CIBU were assessed. The effect of IBU on bacterial adhesion to urothelial cells was also assessed following exposure to trimethoprim/sulfamethoxazole (TMP/SMX) and nitrofurantoin. Bacterial growth was not affected by IBU. Further, only at high levels of IBU not regularly found in the bladder was there a significant increase in E. faecalis 1131 attachment at growth inhibitory concentrations of TMP/SMX. There was no effect on the attachment of E. faecalis or E. coli to urothelial cells in the presence of nitrofurantoin. These studies indicate that the beneficial effects of IBU for UTI management are likely mediated through its anti-inflammatory properties rather than direct interactions with uropathogens in the bladder.

Host and Bacterial Markers that Differ in Children with Cystitis and Pyelonephritis

OBJECTIVE

To determine whether treatment for urinary tract infections in children could be individualized using biomarkers for acute pyelonephritis.

STUDY DESIGN

We enrolled 61 children with febrile urinary tract infections, collected blood and urine samples, and performed a renal scan within 2 weeks of diagnosis to identify those with pyelonephritis. Renal scans were interpreted centrally by 2 experts. We measured inflammatory proteins in blood and urine using LUMINEX or an enzyme-linked immunosorbent assay. We evaluated serum RNA expression using RNA sequencing in a subset of children. Finally, for children with Escherichia coli isolated from urine cultures, we performed a polymerase chain reaction for 4 previously identified virulence genes.

RESULTS

Urinary markers that best differentiated pyelonephritis from cystitis included chemokine (C-X-C motif) ligand (CXCL)1, CXCL9, CXCL12, C-C motif chemokine ligand 2, INF γ, and IL-15. Serum procalcitonin was the best serum marker for pyelonephritis. Genes in the interferon-γ pathway were upregulated in serum of children with pyelonephritis. The presence of E coli virulence genes did not correlate with pyelonephritis.

CONCLUSIONS

Immune response to pyelonephritis and cystitis differs quantitatively and qualitatively; this may be useful in differentiating these 2 conditions.