Host-pathogen interactions in urinary tract infection

Different factors control long-term versus short-term outcomes for bacterial colonisation of a urinary catheter

Urinary catheters are used extensively in hospitals and long-term care and they are highly prone to infection. Understanding the pathways by which bacteria colonise a urinary catheter could guide strategies to mitigate infection, but quantitative models for this colonisation process are lacking. Here we present a mathematical model for bacterial colonisation of a urinary catheter that integrates population dynamics and fluid dynamics. The model describes bacteria migrating up the outside surface of the catheter, spreading into the bladder and being swept through the catheter lumen. Computer simulations of the model reveal that clinical outcomes for long-term versus short-term catheterisation are controlled by different factors: the rate of urine production by the kidneys as opposed to urethral length, catheter surface properties and bacterial motility. Our work may help explain variable susceptibility to catheter-associated urinary tract infection (CAUTI) among individuals and the mixed success of antimicrobial surface coatings. Our model suggests that for long-term catheterised patients, increasing fluid intake or reducing residual urine volume in the bladder may help prevent infection, while antimicrobial surface coatings are predicted to be effective only for short-term catheterised patients. Therefore, different catheter management strategies could be rationally targeted to long-term vs short-term catheterised patients.

Characterization and therapeutic potential of phage vB_Eco_ZCEC08 against multidrug-resistant uropathogenic Escherichia coli

BACKGROUND

Urinary tract infections (UTIs) caused by antibiotic-resistant bacteria have become a significant public health concern. The increasing ineffectiveness of antibiotics has led to a renewed focus on investigating other strategies, such as bacteriophages, to target specific pathogenic bacteria and prevent future resistance.

RESULTS

This study reports the isolation and characterization of bacteriophage vB_Eco_ZCEC08 targeting uropathogenic Escherichia coli (UPEC). Phage vB_Eco_ZCEC08 is morphologically a non-contractile tailed phage that exhibits strong lytic activity against UPEC with a short latent period of less than 15 min and a lysis time of 20 min to produce a high burst of around 900 phage particles per host cell. vB_Eco_ZCEC08 phage activity demonstrated exceptional stability against temperature [-80-60 ̊C], pH [2-11], UV exposure and incubation in artificial human urine. The phage effectively reduced UPEC counts over a range of infection rates, with MOI 1 the most effective, and which resulted in the limited emergence of phage-insensitive bacteria. A whole-genome study of the 47.926 bp vB_Eco_ZCEC08 phage identified one tRNA gene and 84 predicted genes. Comparative genomics and phylogenetic analysis suggest that the vB_Eco_ZCEC08 phage belongs to the same genus as the Salmonella phage vB_SenS_ST1 but represents a new species. Phage vB_Eco_ZCEC08 showed minimal cytotoxicity against human urinary bladder cancer and skin fibroblast cell lines.

CONCLUSION

vB_Eco_ZCEC08 phage demonstrates strong selective lytic activity against UPEC in the absence of any lysogenic behavior. These properties coupled with inherent physiochemical stability and low cytotoxicity support the development of vB_Eco_ZCEC08 as an alternative treatment for multidrug-resistant UPEC.

Anti-inflammatory drugs as potential antimicrobial agents: a review

The association and causal role of infectious agents in chronic inflammatory diseases have major implications for public health, treatment, and prevention. Pharmacological treatment of combined infectious and inflammatory diseases requires the administration of multiple drugs, including antibiotics and anti-inflammatory drugs. However, this can cause adverse effects, and therefore, dual-action drugs need to be developed. Anti-inflammatory drugs that have already shown antimicrobial properties appear to be promising candidates. NSAIDs, namely aceclofenac, diclofenac, and ibuprofen, were tested in clinical trials with patients diagnosed with uncomplicated urinary tract infections (UTIs) and cellulitis. The administration of ibuprofen, a drug tested in the highest number of studies, resulted in symptom resolution in patients with UTIs. Additionally, ibuprofen caused a high survival rate in mice infected with Pseudomonas aeruginosa and demonstrated potent in vitro antibacterial effects against Bacillus cereus, Escherichia coli, and Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA) (MIC 0.625-2.5 mg/L). For most anti-inflammatory drugs, only data showing their in vitro and in vivo antimicrobial effects are available. Among these, auranofin caused a high survival rate in mice infected with Enterococcus faecium, S. aureus, and Clostridioides difficile. It also produced a strong in vitro growth-inhibitory effect against Streptococcus agalactiae, S. pneumoniae, S. aureus, S. epidermidis, Bacillus subtilis, C. difficile, E. faecalis, E. faecium, and Mycobacterium tuberculosis (MIC 0.0015-5 mg/L). Similarly, aspirin caused a high survival rate in M. tuberculosis-infected mice and strong to moderate in vitro activity against E. coli, B. cereus, P. aeruginosa, Enterobacter aerogenes, Klebsiella pneumoniae and Salmonella choleraesuis (MIC 1.2-5 mg/L). Moreover, topical application of celecoxib resulted in a high reduction in MRSA burden in mice. However, it only caused moderate in vitro effects against S. epidermidis, S. aureus and Bacillus subitilis (MIC 16-64 mg/L). These data suggest that certain non-steroidal anti-inflammatory drugs (NSAIDs) are promising drug candidates for the development of dual-action drugs for the potential treatment of combined infectious and inflammatory diseases such as tuberculosis, musculoskeletal infections and UTIs. Nevertheless, future clinical trials must be conducted to ascertain the antibacterial effect of these NSAIDs before their practical use.

Patient-reported therapeutic benefits of herbal medicinal products in the treatment of gynecological ailments

BACKGROUND

Gynecological ailments have a negative impact on quality of life and productivity. Standard treatment is associated with poor tolerability and other issues related to public health and environment. Herbal Medicinal Products (HMPs) are used traditionally for the treatment of menstrual and menopausal ailments as well as uncomplicated urinary tract infections (uUTIs) for centuries and constitute a suitable addition to current treatment options. HMPs are well tolerated, non-polluting and therapeutically efficacious as evidenced by various clinical studies. Aim of this study was to expand the evidence regarding therapeutic effectiveness of HMPs for the treatment of gynecological complaints by complementing knowledge from clinical studies with real-world evidence from patient-reported outcomes.

METHODS

A data set consisting of patient-reported outcomes regarding the treatment of gynecological ailments (n = 1658) with HMPs was taken from the pharmaco-epidemiological database PhytoVIS. After data preparation excluding all cases of herbal supplements, homeopathic preparations, or non-herbal medicinal products the remaining data (n = 1363) was grouped into the three indications menstrual complaints (n = 222), menopausal complaints (n = 301), and uUTIs (n = 840). We applied descriptive statistical methods (frequency and percentage) with regard to the variables "age", "treatment duration", "severity of symptoms", "therapeutic benefits", and "adverse drug reactions". Thereafter we evaluated the therapeutic benefit of HMPs as well as adverse events.

RESULTS

The majority of the patients (82.2%) in the sample assessed the overall therapeutic effect of HMPs for the treatment of gynecological complaints as beneficial and 90.8% of them perceived no or no significant adverse events. Treatment habits differed depending on the type of complaint. In this context the majority of women with menstrual or menopausal ailments preferred to treat for time period of 1 month or longer, while those affected by uUTIs reduced the application of HMPs to the length of their symptoms. Interestingly women with even strong symptoms relied on the therapeutic benefit of HMPs.

CONCLUSION

Real-world outcome data are an important supplement to clinical data. Our results reveal a favorable benefit-risk ratio of HMPs and help to implement them into novel therapeutic strategies to treat gynecological complaints.

Canine urothelial cell model to study intracellular bacterial community development by uropathogenic Escherichia coli

Urinary tract infections (UTIs) are among the most common bacterial infections of both dogs and humans, with most caused by uropathogenic Escherichia coli (UPEC). Recurrent UPEC infections are a major concern in the treatment and management of UTIs in both species. In humans, the ability of UPECs to form intracellular bacterial communities (IBCs) within urothelial cells has been implicated in recurrent UTIs. However, the role of IBCs has not been explored in the pathogenesis of canine recurrent UTIs. In this study, we identified IBCs in both urine and bladder tissue from dogs with UPEC associated UTIs. In addition, we showed that UPECs derived from canine UTIs form IBCs within primary canine urothelial cells. As in human UTIs, formation of IBCs by canine UPECs correlated with the presence of the fimH gene as those isolates lacking the fimH gene formed fewer IBCs in canine urothelial cells then those harboring the fimH gene. Additionally, UPEC strains from clinical cases classified as recurrent UTIs had higher rates of IBC formation than UPEC strains from non-recurrent UTIs. These IBCs were tolerant to treatment with enrofloxacin, cefpodoxime and doxycycline at 150, 50 and 50 μg/mL respectively, which are representative of the concentrations achieved in canine urine after standard dosing. This is consistent with the clinical perspective that current UTIs are a common condition of dogs and are difficult to manage through antimicrobial treatment. Additionally, the dog could prove to be a powerful model of IBC formation as they are natural models of UPEC-causing UTIs and have similar pathophysiology of IBC formation.

Antibiotic Resistance of Urinary Tract Infection Recurrences in a Large Integrated US Healthcare System

BACKGROUND

Data on antibiotic resistance of uropathogens for urinary tract infection (UTI) recurrences are lacking.

METHODS

In a retrospective cohort of adults at Kaiser Permanente Southern California with culture-confirmed index uncomplicated UTI (uUTI) between January 2016 and December 2020, we examined the number and characteristics of subsequent culture-confirmed UTIs through 2021.

RESULTS

We identified 148 994 individuals with a culture-confirmed index uUTI (88% female, 44% Hispanic; mean age, 51 years [standard deviation, 19 years]), of whom 19% developed a subsequent culture-confirmed UTI after a median 300 days (interquartile range, 126-627 days). The proportion of UTI due to Escherichia coli was highest for index uUTI (79%) and decreased to 73% for sixth UTI (UTI 6) (P for trend < .001), while the proportion due to Klebsiella spp increased from index UTI (7%) to UTI 6 (11%) (P for trend < .001). Nonsusceptibility to ≥1 and ≥3 antibiotic classes was observed in 57% and 13% of index uUTIs, respectively, and was higher for subsequent UTIs (65% and 20%, respectively, for UTI 6). Most commonly observed antibiotic nonsusceptibility patterns included penicillins alone (12%), and penicillins and trimethoprim-sulfamethoxazole plus ≥1 additional antibiotic class (9%).

CONCLUSIONS

Antibiotic nonsusceptibility is common in UTIs and increases with subsequent UTIs. Continuous monitoring of UTI recurrences and susceptibility patterns is needed to guide treatment decisions.

Risk Factors for Recurrent Urinary Tract Infections Among Women in a Large Integrated Health Care Organization in the United States

BACKGROUND

Urinary tract infections (UTIs) occur commonly and often recur. However, recent data on the epidemiology of recurrent UTI (rUTI) are scarce.

METHODS

Between 1 January 2016 and 31 December 2020, index uncomplicated UTIs (uUTIs) from office, emergency department, hospital, and virtual care settings were identified from the electronic health records of women at Kaiser Permanente Southern California. We defined rUTI as ≥3 UTIs within 365 days or ≥2 UTIs within 180 days. We determined the proportion of women with cystitis index uUTI who had rUTI, and we examined factors associated with rUTIs using modified multivariable Poisson regression.

RESULTS

Among 374 171 women with cystitis index uUTI, 54 318 (14.5%) had rUTI. A higher proportion of women with rUTI vs those without rUTI were aged 18 to 27 or ≥78 years at index uUTI (19.7% vs 18.7% and 9.0% vs 6.0%, respectively), were immunocompromised, or had a positive urine culture result at index uUTI. In multivariable analyses, characteristics associated with rUTI included younger or older age (48-57 vs 18-27 years: adjusted risk ratio [aRR], 0.83 [95% CI, .80-.85]; ≥78 vs 18-27 years: aRR, 1.07 [95% CI, 1.03-1.11]), Charlson Comorbidity Index (≥3 vs 0: aRR, 1.12 [95% CI, 1.08-1.17]), and diabetes mellitus (aRR, 1.07 [95% CI, 1.04-1.10]). More frequent prior-year outpatient and emergency department encounters, oral antibiotic and oral contraceptive prescriptions, positive culture result at index uUTI, and antibiotic-resistant organisms were also associated with increased risk of rUTI.

CONCLUSIONS

The high risk of rUTI among women with cystitis is concerning, especially given previous reports of increasing UTI incidence. Current assessment of the epidemiology of rUTI may guide the development of preventive interventions against UTI.

Enzymes in Synergy: Bacteria Specific Molecular Probe for Locoregional Imaging of Urinary Tract Infection in vivo

Uropathogenic Escherichia coli (UPECs) is a leading cause for urinary tract infections (UTI), accounting for 70-90 % of community or hospital-acquired bacterial infections owing to high recurrence, imprecision in diagnosis and management, and increasing prevalence of antibiotic resistance. Current methods for clinical UPECs detection still rely on labor-intensive urine cultures that impede rapid and accurate diagnosis for timely UTI therapeutic management. Herein, we developed a first-in-class near-infrared (NIR) UPECs fluorescent probe (NO-AH) capable of specifically targeting UPECs through its collaborative response to bacterial enzymes, enabling locoregional imaging of UTIs both in vitro and in vivo. Our NO-AH probe incorporates a dual protease activatable moiety, which first reacts with OmpT, an endopeptidase abundantly present on the outer membrane of UPECs, releasing an intermediate amino acid residue conjugated with a NIR hemicyanine fluorophore. Such liberated fragment would be subsequently recognized by aminopeptidase (APN) within the periplasm of UPECs, activating localized fluorescence for precise imaging of UTIs in complex living environments. The peculiar specificity and selectivity of NO-AH, facilitated by the collaborative action of bacterial enzymes, features a timely and accurate identification of UPECs-infected UTIs, which could overcome misdiagnosis in conventional urine tests, thus opening new avenues towards reliable UTI diagnosis and personalized antimicrobial therapy management.

Draft genome of three uropathogenic Escherichia coli strains

Uropathogenic Escherichia coli (UPEC) remains the main etiological agent of urinary tract infections affecting females and males. The draft genome sequence of three strains of UPEC isolated from senior citizens and pregnant women in the state of Puebla, Mexico, is reported here.

An efficient ratiometric fluorescence and colorimetric dual-mode probe for convenient determination of nitrite in real samples and E. coli

Developing an effective and convenient nitrite detection method is indispensable in food safety, environmental monitoring, clinical diagnosis of diseases, and many other areas. Herein, a dicyanoisophorone derivative, TMN-NH2 with large Stokes shift and near-infrared (NIR) emission, was proposed as a ratiometric fluorescence and colorimetric dual-mode probe for the rapid determination of NO2- in acidic media, showing excellent selectivity and high sensitivity. The sensing mechanism is based on the diazotization of TMN-NH2 with NO2- and subsequent diazonium salt hydrolysis to form a hydroxyl-substituted product (TMN-OH). Under the optimized conditions of reaction and detection, a new quantitative analysis method based on TMN-NH2 was established for NO2- detection, exhibiting good linear relationships to NO2- in the range of 0.5 to 15 μM with practical detection limits of 26.6 nM and 17.6 nM for the colorimetric and fluorescent readout, respectively. The quantitative detection of NO2- in real samples demonstrated satisfactory recoveries and repeatability. Moreover, TMN-NH2 was successfully applied for monitoring NO2- in Escherichia coli by confocal fluorescence imaging.

Molecular Characterization of High and Low Virulent Escherichia coli Clinical Strains Isolated from Patients with Urinary Tract Infections with or without Bacteremia in Southern Taiwan

Objective

The most common extraintestinal pathogen and infection site is uropathogenic Escherichia coli (UPEC), which causes urinary tract infections (UTIs). UPEC is also a common pathogen in bloodstream infections; in severe cases, it can lead to death. Although host and bacterial virulence factors have been demonstrated to be associated with UTI pathogenesis, the role of the related contributing factors in UTI and urinary source bacteremia is not yet fully understood. This study aimed to compare and analyze the factors contributing to urinary bacteremia in patients with UTI.

Methods

A total of 171 E. coli strains collected from patients with UTI and urinary source bacteremia at Chiayi Christian Hospital were used. Phylogenetic groups and virulence factors were determined using PCR. Drug resistance patterns were determined using the disk diffusion assay.

Results

Previous studies have demonstrated that fimbriae and papGII may be associated with first-step infections and severe UTIs, respectively. As expected, highly virulent E. coli strains (belonging to the phylogenetic B2 and D groups) were dominant in the bacteremic UTI (90%) and UTI (86.27%) groups. However, our results showed that the UTI group had a significantly higher prevalence of sfa/focDE (belonging to the S and FIC fimbriae) than the bacteremic UTI group (29.4% vs 12.5%; p=0.008). In the bacteremic group, we found that sfa/focDE was only detected in highly virulent strains. The bacteremic UTI group had a significantly higher prevalence of papGII (belonging to P fimbriae) than the UTI group (55.8% vs 37.3%; p=0.026). In addition, the P fimbriae gene cluster, including papC, papEF, and papGII, was predominant in highly virulent strains. Notably, our results show that multidrug-resistant (MDR) strains were significantly less virulent than non MDR strains.

Conclusion

Taken together, our results provide insights into the contributing factors in patients with UTI and urinary bacteremia.

Competitive fitness of asymptomatic bacteriuria E. coli strain 83972 against uropathogens in human urine

Urinary tract infection (UTI) is one of the most common bacterial infections worldwide. The main causative agent of UTI is uropathogenic Escherichia coli (UPEC). There is an immediate need for novel prophylactic and treatment strategies against UTI because of the increasing incidence of antimicrobial resistance among uropathogens. ABU 83972, an asymptomatic bacteriuria-causing E. coli strain, prevents UTI by suppressing the colonization of UPEC. However, the nature of competition and growth repression of UPEC by ABU 83972 is unclear and is the subject of our investigation. Here, we characterized the growth kinetics of ABU 83972 and uropathogens in human urine and laboratory media. Next, we performed a series of competitive co-culture experiments where ABU 83972 and uropathogens were inoculated at a 1:1 ratio in human urine and in various media, and their relative abundance was determined. In human urine, ABU 83972 outcompeted UPEC and additional uropathogens, reaching up to 90% of the total population after 24 hours of incubation. In contrast, UPEC outcompeted ABU 83972 in LB and M9 minimal media and exhibited superior colonization than ABU 83972 in the mouse urinary bladder. Since engineered living materials (ELMs) can be used to retain an organism of interest in a particular location, we developed ABU 83972-containing ELMs that effectively outcompeted UPEC in human urine. In summary, our work establishes that ABU 83972 outcompetes UPEC in a milieu- and cell-density-dependent manner, highlighting the importance of the metabolites and nutrients found in the human urine as determinants of the competitive fitness of ABU 83972.

Polyvalent Bacterial Lysate with Potential Use to Treatment and Control of Recurrent Urinary Tract Infections

Overuse of antimicrobials has greatly contributed to the increase in the emergence of multidrug-resistant bacteria, a situation that hinders the control and treatment of infectious diseases. This is the case with urinary tract infections (UTIs), which represent a substantial percentage of worldwide public health problems, thus the need to look for alternatives for their control and treatment. Previous studies have shown the usefulness of autologous bacterial lysates as an alternative for the treatment and control of UTIs. However, a limitation is the high cost of producing individual immunogens. At the same time, an important aspect of vaccines is their immunogenic amplitude, which is the reason why they must be constituted of diverse antigenic components. In the case of UTIs, the etiology of the disease is associated with different bacteria, and even Escherichia coli, the main causal agent of the disease, is made up of several antigenic variants. In this work, we present results on the study of a bacterial lysate composed of 10 serotypes of Escherichia coli and by Klebsiella pneumoniae, Klebsiella aerogenes, Enterococcus faecalis, Proteus mirabilis, Citrobacter freundii, and Staphylococcus haemolyticus. The safety of the compound was tested on cells in culture and in an animal model, and its immunogenic capacity by analysing in vitro human and murine macrophages (cell line J774 A1). The results show that the polyvalent lysate did not cause damage to the cells in culture or alterations in the animal model used. The immunostimulatory activity assay showed that it activates the secretion of TNF-α and IL-6 in human macrophages and TNF-α in murine cells. The obtained results suggest that the polyvalent lysate evaluated can be an alternative for the treatment and control of chronic urinary tract infections, which will reduce the use of antimicrobials.

Multiple Infections, Nutrient Deficiencies, and Inflammation as Determinants of Anemia and Iron Status during Pregnancy: The MINDI Cohort

In pregnant women with multiple infections, nutrient deficiencies, and inflammation (MINDI), the study of anemia and iron status is limited. For this cross-sectional study (n = 213 Panamanian indigenous women), we investigated if hemoglobin, anemia (Hb < 110 g/L), ferritin, serum iron, serum transferrin receptor, and hepcidin were associated with (1) maternal nutritional status and supplementation practices, (2) biomarkers of inflammation, and (3) presence/absence of infections. Hierarchical generalized linear and logistic regression models and dominance analyses identified the relative importance of these predictors. Anemia (38%), which was likely underestimated due to low plasma volume (95%), was associated with lower ferritin, vitamin A, and weight-for-height, suggesting anemia of undernutrition. Inflammation was not associated with Hb or anemia; nevertheless, higher CRP was associated with increased odds of low serum iron and higher ferritin and hepcidin, indicating iron restriction due to inflammation. The length of iron supplementation did not enter models for anemia or iron indicators, but a multiple nutrient supplement was associated with higher ferritin and hepcidin. Moreover, iron supplementation was associated with higher odds of vaginal trichomoniasis but lower odds of caries and bacterial vaginosis. The complex pathogenesis of anemia and iron deficiency in MINDI settings may require other interventions beyond iron supplementation.

The Role of Metabolomics and Microbiology in Urinary Tract Infection

One of the common illnesses that affect women's physical and mental health is urinary tract infection (UTI). The disappointing results of empirical anti-infective treatment and the lengthy time required for urine bacterial culture are two issues. Antibiotic misuse is common, especially in females who experience recurrent UTI (rUTI). This leads to a higher prevalence of antibiotic resistance in the microorganisms that cause the infection. Antibiotic therapy will face major challenges in the future, prompting clinicians to update their practices. New testing techniques are making the potential association between the urogenital microbiota and UTIs increasingly apparent. Monitoring changes in female urinary tract (UT) microbiota, as well as metabolites, may be useful in exploring newer preventive treatments for UTIs. This review focuses on advances in urogenital microbiology and organismal metabolites relevant to the identification and handling of UTIs in an attempt to provide novel methods for the identification and management of infections of the UT. Particular attention is paid to the microbiota and metabolites in the patient's urine in relation to their role in supporting host health.

Copper affects virulence and diverse phenotypes of uropathogenic Proteus mirabilis

BACKGROUND

Copper plays a role in urinary tract infection (UTI) and urinary copper content is increased during Proteus mirabilis UTI. We therefore investigated the effect of copper on uropathogenic P. mirabilis and the underlying mechanisms, focusing on the virulence associated aspects.

METHODS

Mouse colonization, swarming/swimming assays, measurement of cell length, flagellin level and urease activity, adhesion/invasion assay, biofilm formation, killing by macrophages, oxidative stress susceptibility, OMPs analysis, determination of MICs and persister cell formation, RT-PCR and transcriptional reporter assay were performed.

RESULTS

We found that copper-supplemented mice were more resistant to be colonized in the urinary tract, together with decreased swarming/swimming, ureases activity, expression of type VI secretion system and adhesion/invasion to urothelial cells and increased killing by macrophages of P. mirabilis at a sublethal copper level. However, bacterial biofilm formation and resistance to oxidative stress were enhanced under the same copper level. Of note, the presence of copper led to increased ciprofloxacin MIC and more persister cell formation against ampicillin. In addition, the presence of copper altered the outer membrane protein profile and triggered expression of RcsB response regulator. For the first time, we unveiled the pleiotropic effects of copper on uropathogenic P. mirabilis, especially for induction of bacterial two-component signaling system regulating fitness and virulence.

CONCLUSION

The finding of copper-mediated virulence and fitness reinforced the importance of copper for prevention and therapeutic interventions against P. mirabilis infections. As such, this study could facilitate the copper-based strategies against UTI by P. mirabilis.

Pathogen non-planktonic phases within the urinary tract impact early infection and resistance evolution

Treatment of urinary tract infections and the prevention of their recurrence is a pressing global health problem. In a urinary infection, pathogenic bacteria not only reside in the bladder lumen but also attach to and invade the bladder tissue. Planktonic, attached, and intracellular bacteria face different selection pressures from physiological processes such as micturition, immune response, and antibiotic treatment. Here, we use a mathematical model of the initial phase of infection to unravel the effects of these different selective pressures on the ecological and evolutionary dynamics of urinary infections. We explicitly model planktonic bacteria in the bladder lumen, bacteria attached to the bladder wall, and bacteria that have invaded the epithelial cells of the bladder. We find that the presence of non-planktonic bacteria substantially increases the risk of infection establishment and affects evolutionary trajectories leading to resistance during antibiotic treatment. We also show that competitive inoculation with a fast-growing non-pathogenic strain can reduce the pathogen load and increase the efficacy of an antibiotic, but only if the antibiotic is used in moderation. Our study shows that including different compartments is essential to create more realistic models of urinary infections, which may help guide new treatment strategies.

Oxybutynin ameliorates LPS-induced inflammatory response in human bladder epithelial cells

Urinary tract infection (UTI) mainly results from bacterial infections in the urinary tract and markedly impacts the normal lives of millions of patients worldwide. The infection and damage to urethral epithelial cells is the first and key step of UTI development and is a critical target for treating clinical UTI. Oxybutynin, an agent for treating urinary incontinence, is recently claimed with protective effects on bladder ultrastructure. Our study will assess the impact of Oxybutynin on inflammation in lipopolysaccharide (LPS)-stimulated bladder epithelial cells. Bladder epithelial T24 cells were treated with 1 μg/mL LPS with or without 10 and 20 μM Oxybutynin for 24 h. Increased levels of oxidative stress (OS) biomarkers, such as reactive oxygen species, 8-hydroxy-2'-deoxyguanosine, malondialdehyde, as well as upregulated inducible nitric oxide synthase and promoted release of nitric oxide, were observed in LPS-managed T24 cells, all of which were signally suppressed by Oxybutynin. Furthermore, severe inflammatory responses, including enhanced release of cytokines, upregulated matrix metallopeptidase-2 (MMP-2) and MMP-9, and raised monocyte chemoattractant protein-1 level, were found in LPS-challenged T24 cells, which were markedly reversed by Oxybutynin. Moreover, the activated toll-1ike receptor 4/nuclear factor-κB pathway observed in LPS-managed T24 cells was repressed by Oxybutynin. Collectively, Oxybutynin mitigated LPS-induced inflammatory response in human bladder epithelial cells.

Structure-activity relationship of drug conjugated polymeric materials against uropathogenic bacteria colonization under in vitro and in vivo settings

The human world has been plagued with different kinds of bacterial infections from time immemorial. The increased development of resistance towards commercial antibiotics has made these bacterial infections an even more critical challenge. Bacteria have modified their mode of interactions with different types of commercial drugs by bringing changes to the receptor proteins or by other resisting mechanisms like drug efflux. Various chemical approaches have been made to date to fight against these smart adapting species. Towards this, we hypothesize chemically modifying the commercial antibacterial drugs in order to deceive the bacteria and destroy the bacterial biomass. In this study, different molecular weight polyethyleneimines are taken and conjugated with some well-known commercial drugs like penicillin and chloramphenicol to explore their antibacterial properties against some of the laboratory and uro-pathogenic strains of Gram-positive and Gram-negative bacteria. A detailed structure-activity relationship of these polymeric prodrug-like materials has been evaluated to determine the optimum formulation. The standardized system not only shows significant ∼90% bacterial killing in liquid broth culture, but also demonstrates promising bacterial inhibition towards biofilm formation for the pathogenic strains on inanimate surfaces like urinary catheters and on an in vivo mouse skin abrasion model. The reported bioactive polymeric materials can be successfully used for widespread therapeutic applications with promising medical relevance.

Substances Secreted by Lactobacillus spp. from the Urinary Tract Microbiota Play a Protective Role against Proteus mirabilis Infections and Their Complications

Proteus mirabilis urinary tract infections can lead to serious complications such as development of urinary stones. Lactobacillus spp., belonging to the natural microbiota of the urinary tract, exhibit a number of antagonistic mechanisms against uropathogens, including the secretion of organic acids. In this study, we determined the anti-adhesion, anti-cytotoxicity and anti-crystallization properties of the substances secreted by Lactobacillus. For this purpose, membrane inserts with a pore diameter 0.4 μm were used, which prevent mixing of cultured cells, simultaneously enabling the diffusion of metabolic products. The intensity of crystallization was assessed by measuring the levels of Ca2+, Mg2+ and NH3 and by observing crystals using microscopic methods. The cytotoxicity of the HCV-29 cell line was determined using the LDH and MTT assays, and the impact of lactobacilli on P. mirabilis adhesion to the bladder epithelium was assessed by establishing CFU/mL after cell lysis. It was shown that in the presence of L. gasseri the adhesion of P. mirabilis and the cytotoxicity of the cells decreased. The degree of crystallization was also inhibited in all experimental models. Moreover, it was demonstrated that L. gasseri is characterized by the secretion of a high concentration of L-lactic acid. These results indicate that L-lactic acid secreted by L. gasseri has a significant impact on the crystallization process and pathogenicity of P. mirabilis.

Virulence-associated genes and antimicrobial resistance patterns in bacteria isolated from pregnant and nonpregnant women with urinary tract infections: the risk of neonatal sepsis

Uropathogenic Escherichia coli (UPEC) is classified as the major causative agent of urinary tract infections (UTIs). UPEC virulence and antibiotic resistance can lead to complications in pregnant women and (or) newborns. Therefore, the aim of this study was to determine the etiological agents of UTIs, as well as to identify genes related to virulence factors in bacteria isolated from pregnant and nonpregnant women. A total of 4506 urine samples were collected from pregnant and nonpregnant women. Urine cultures were performed, and PCR was used to identify phylogroups and virulence-related genes. Antibiotic resistance profiles were determined. The incidence of UTIs was 6.9% (pregnant women, n = 206 and nonpregnant women, n = 57), and UPEC belonging to phylogroup A was the most prevalent. The presence of genes related to capsular protection, adhesins, iron acquisition, and serum protection in UPEC was associated with not being pregnant, while the presence of genes related to adhesins was associated with pregnancy. Bacteria isolated from nonpregnant women were more resistant to antibiotics; 36.5% were multidrug resistant, and 34.9% were extensively drug resistant. Finally, UTIs were associated with neonatal sepsis risk, particularly in pregnant women who underwent cesarean section while having a UTI caused by E. coli. In conclusion, UPEC isolated from nonpregnant women carried more virulence factors than those isolated from pregnant women, and maternal UTIs were associated with neonatal sepsis risk.

Uropathogen and host responses in pyelonephritis

Urinary tract infections (UTIs) are among the most common bacterial infections seen in clinical practice. The ascent of UTI-causing pathogens to the kidneys results in pyelonephritis, which can trigger kidney injury, scarring and ultimately impair kidney function. Despite sizable efforts to understand how infections develop or are cleared in the bladder, our appreciation of the mechanisms by which infections develop, progress or are eradicated in the kidney is limited. The identification of virulence factors that are produced by uropathogenic Escherichia coli to promote pyelonephritis have begun to fill this knowledge gap, as have insights into the mechanisms by which kidney tubular epithelial cells oppose uropathogenic E. coli infection to prevent or eradicate UTIs. Emerging data also illustrate how specific cellular immune responses eradicate infection whereas other immune cell populations promote kidney injury. Insights into the mechanisms by which uropathogenic E. coli circumvent host immune defences or antibiotic therapy to cause pyelonephritis is paramount to the development of new prevention and treatment strategies to mitigate pyelonephritis and its associated complications.

Immune defenses in the urinary tract

Recent advances in preclinical modeling of urinary tract infections (UTIs) have enabled the identification of key facets of the host response that influence pathogen clearance and tissue damage. Here, we review new insights into the functions of neutrophils, macrophages, and antimicrobial peptides in innate control of uropathogens and in mammalian infection-related tissue injury and repair. We also discuss novel functions for renal epithelial cells in innate antimicrobial defense. In addition, epigenetic modifications during bacterial cystitis have been implicated in bladder remodeling, conveying susceptibility to recurrent UTI. In total, contemporary work in this arena has better defined host processes that shape UTI susceptibility and severity and might inform the development of novel preventive and therapeutic approaches for acute and recurrent UTI.

CpxA/R-Controlled Nitroreductase Expression as Target for Combinatorial Therapy against Uropathogens by Promoting Reactive Oxygen Species Generation

The antibiotic resistances emerged in uropathogens lead to accumulative treatment failure and recurrent episodes of urinary tract infection (UTI), necessitating more innovative therapeutics to curb UTI before systematic infection. In the current study, the combination of amikacin and nitrofurantoin is found to synergistically eradicate Gram-negative uropathogens in vitro and in vivo. The mechanistic analysis demonstrates that the amikacin, as an aminoglycoside, induced bacterial envelope stress by introducing mistranslated proteins, thereby constitutively activating the cpxA/R two-component system (Cpx signaling). The activation of Cpx signaling stimulates the expression of bacterial major nitroreductases (nfsA/nfsB) through soxS/marA regulons. As a result, the CpxA/R-dependent nitroreductases overexpression generates considerable quantity of lethal reactive intermediates via nitroreduction and promotes the prodrug activation of nitrofurantoin. As such, these actions together disrupt the bacterial cellular redox balance with excessively-produced reactive oxygen species (ROS) as "Domino effect", accelerating the clearance of uropathogens. Although aminoglycosides are used as proof-of-principle to elucidate the mechanism, the synergy between nitrofurantoin is generally applicable to other Cpx stimuli. To summarize, this study highlights the potential of aminoglycoside-nitrofurantoin combination to replenish the arsenal against recurrent Gram-negative uropathogens and shed light on the Cpx signaling-controlled nitroreductase as a potential target to manipulate the antibiotic susceptibility.

Urinary Tract Infections Caused by Uropathogenic Escherichia coli: Mechanisms of Infection and Treatment Options

Urinary tract infections (UTIs) are common bacterial infections that represent a severe public health problem. They are often caused by Escherichia coli (E. coli), Klebsiella pneumoniae (K. pneumonia), Proteus mirabilis (P. mirabilis), Enterococcus faecalis (E. faecalis), and Staphylococcus saprophyticus (S. saprophyticus). Among these, uropathogenic E. coli (UPEC) are the most common causative agent in both uncomplicated and complicated UTIs. The adaptive evolution of UPEC has been observed in several ways, including changes in colonization, attachment, invasion, and intracellular replication to invade the urothelium and survive intracellularly. While antibiotic therapy has historically been very successful in controlling UTIs, high recurrence rates and increasing antimicrobial resistance among uropathogens threaten to greatly reduce the efficacy of these treatments. Furthermore, the gradual global emergence of multidrug-resistant UPEC has highlighted the need to further explore its pathogenesis and seek alternative therapeutic and preventative strategies. Therefore, a thorough understanding of the clinical status and pathogenesis of UTIs and the advantages and disadvantages of antibiotics as a conventional treatment option could spark a surge in the search for alternative treatment options, especially vaccines and medicinal plants. Such options targeting multiple pathogenic mechanisms of UPEC are expected to be a focus of UTI management in the future to help combat antibiotic resistance.

Sequencing and Characterization of M. morganii Strain UM869: A Comprehensive Comparative Genomic Analysis of Virulence, Antibiotic Resistance, and Functional Pathways

Morganella morganii is a Gram-negative opportunistic Enterobacteriaceae pathogen inherently resistant to colistin. This species causes various clinical and community-acquired infections. This study investigated the virulence factors, resistance mechanisms, functional pathways, and comparative genomic analysis of M. morganii strain UM869 with 79 publicly available genomes. The multidrug resistance strain UM869 harbored 65 genes associated with 30 virulence factors, including efflux pump, hemolysin, urease, adherence, toxin, and endotoxin. Additionally, this strain contained 11 genes related to target alteration, antibiotic inactivation, and efflux resistance mechanisms. Further, the comparative genomic study revealed a high genetic relatedness (98.37%) among the genomes, possibly due to the dissemination of genes between adjoining countries. The core proteome of 79 genomes contains the 2692 core, including 2447 single-copy orthologues. Among them, six were associated with resistance to major antibiotic classes manifested through antibiotic target alteration (PBP3, gyrB) and antibiotic efflux (kpnH, rsmA, qacG; rsmA; CRP). Similarly, 47 core orthologues were annotated to 27 virulence factors. Moreover, mostly core orthologues were mapped to transporters (n = 576), two-component systems (n = 148), transcription factors (n = 117), ribosomes (n = 114), and quorum sensing (n = 77). The presence of diversity in serotypes (type 2, 3, 6, 8, and 11) and variation in gene content adds to the pathogenicity, making them more difficult to treat. This study highlights the genetic similarity among the genomes of M. morganii and their restricted emergence, mostly in Asian countries, in addition to their growing pathogenicity and resistance. However, steps must be taken to undertake large-scale molecular surveillance and to direct suitable therapeutic interventions.

Synthetic and natural antimicrobials as a control against food borne pathogens: A review

Food borne pathogens are one of the most common yet concerning cause of illnesses around the globe. These microbes invade the body via food items, through numerous mediums of contamination and it is impossible to completely eradicate these organisms from food. Extensive research has been made regarding their treatment. Unfortunately, the only available treatment currently is by antibiotics. Recent exponential increase in antibiotic resistance and the side effect of synthetic compounds have established a need for alternate therapies that could be utilized either on their own or along with antibiotics to provide protection against food-borne diseases. The aim of this review is to provide information regarding some common food borne diseases, their current and possible natural treatment. It will include details regarding some common foodborne pathogens, the disease they cause, prevalence, manifestations and treatment of the respective disease. Some natural modes of potential treatment will be summarized, which including phytochemicals, derived from plants either as crude extracts or as purified form and Bacteriocins as microbial based treatment, obtained from various types of bacteria. The paper will describe their mechanism of action, classification, susceptible organisms, some antimicrobial compounds and producing organisms, application in food systems and as potential treatment. Along with that, synthetic treatment i.e., antibiotics will be discussed including the first-line treatment of some common food borne infections, prevalence and mechanism of resistance against antibiotics in the pathogens.

An immunoresponsive three-dimensional urine-tolerant human urothelial model to study urinary tract infection

Introduction

Murine models of urinary tract infection (UTI) have improved our understanding of host-pathogen interactions. However, given differences between rodent and human bladders which may modulate host and bacterial response, including certain biomarkers, urothelial thickness and the concentration of urine, the development of new human-based models is important to complement mouse studies and to provide a more complete picture of UTI in patients.

Methods

We originally developed a human urothelial three-dimensional (3D) model which was urine tolerant and demonstrated several urothelial biomarkers, but it only achieved human thickness in heterogenous, multi-layered zones and did not demonstrate the comprehensive differentiation status needed to achieve barrier function. We optimised this model by altering a variety of conditions and validated it with microscopy, flow cytometry, transepithelial electrical resistance and FITC-dextran permeability assays to confirm tissue architecture, barrier integrity and response to bacterial infection.

Results

We achieved an improved 3D urine-tolerant human urothelial model (3D-UHU), which after 18-20 days of growth, stratified uniformly to 7-8 layers comprised of the three expected, distinct human cell types. The apical surface differentiated into large, CD227+ umbrella-like cells expressing uroplakin-1A, II, III, and cytokeratin 20, all of which are important terminal differentiation markers, and a glycosaminoglycan layer. Below this layer, several layers of intermediate cells were present, with a single underlying layer of CD271+ basal cells. The apical surface also expressed E-cadherin, ZO-1, claudin-1 and -3, and the model possessed good barrier function. Infection with both Gram-negative and Gram-positive bacterial classes elicited elevated levels of pro-inflammatory cytokines and chemokines characteristic of urinary tract infection in humans and caused a decrease in barrier function.

Discussion

Taken together, 3D-UHU holds promise for studying host-pathogen interactions and host urothelial immune response.

Vesicoureteral Reflux and Innate Immune System: Physiology, Physiopathology, and Clinical Aspects

Vesicoureteral reflux represents one of the most concerning topics in pediatric nephrology due to its frequency, clinical expression with the potential to evolve into chronic kidney disease, and last but not least, its socio-economic implications. The presence of vesicoureteral reflux, the occurrence of urinary tract infections, and the development of reflux nephropathy, hypertension, chronic kidney disease, and finally, end-stage renal disease represent a progressive spectrum of a single physiopathological condition. For the proper management of these patients with the best clinical outcomes, and in an attempt to prevent the spread of uropathogens' resistance to antibacterial therapy, we must better understand the physiopathology of urinary tract infections in patients with vesicoureteral reflux, and at the same time, we should acknowledge the implication and response of the innate immune system in this progressive pathological condition. The present paper focuses on theoretical aspects regarding the physiopathology of vesicoureteral reflux and the interconditionality between urinary tract infections and the innate immune system. In addition, we detailed aspects regarding cytokines, interleukins, antimicrobial peptides, and proteins involved in the innate immune response as well as their implications in the physiopathology of reflux nephropathy. New directions of study should focus on using these innate immune system effectors as diagnostic and therapeutic tools in renal pathology.

Development and radiosterilization of new hydrazono-quinoline hybrids as DNA gyrase and topoisomerase IV inhibitors: Antimicrobial and hemolytic activities against uropathogenic isolates with molecular docking study

This study aimed to synthesize new potent quinoline derivatives based on hydrazone moieties and evaluate their antimicrobial activity. The newly synthesized hydrazono-quinoline derivatives 2, 5a, 9, and 10b showed the highest antimicrobial activity with MIC values ≤1.0 μg/ml against bacteria and ≤8.0 μg/ml against the fungi. Further, these derivatives exhibited bactericidal and fungicidal effects with MBC/MIC and MFC/MIC ratio ≤4. Surprisingly, the most active compounds displayed good inhibition to biofilm formation with MBEC values ranging between (40.0 ± 10.0 - 230.0 ± 31.0) and (67.0 ± 24.0 - 347.0 ± 15.0) μg/ml against Staphylococcus aureus and Pseudomonas aeruginosa, respectively. The hemolytic assays confirmed that the hydrazono-quinoline derivatives are non-toxic with low % lysis values ranging from 4.62% to 14.4% at a 1.0 mg/ml concentration. Besides, compound 5a exhibited the lowest hemolytic activity value of ~4.62%. Furthermore, the study suggests that the hydrazono-quinoline analogs exert their antibacterial activity as dual inhibitors for DNA gyrase and DNA topoisomerase IV enzymes with IC₅₀ values ranging between (4.56 ± 0.3 - 21.67 ± 0.45) and (6.77 ± 0.4 - 20.41 ± 0.32) μM, respectively. Additionally, the recent work advocated that compound 5a showed the reference SAL at the ɣ-radiation dose of 10.0 kGy in the sterilization process without affecting its chemical structure. Finally, the in silico drug-likeness, toxicity properties, and molecular docking simulation were performed. Besides, the result exhibited good oral-bioavailability, lower toxicity prediction, and lower binding energy with good binding mode rather than the positive control.

In Vivo Role of Two-Component Regulatory Systems in Models of Urinary Tract Infections

Two-component signaling systems (TCSs) are finely regulated mechanisms by which bacteria adapt to environmental conditions by modifying the expression of target genes. In bacterial pathogenesis, TCSs play important roles in modulating adhesion to mucosal surfaces, resistance to antibiotics, and metabolic adaptation. In the context of urinary tract infections (UTI), one of the most common types infections causing significant health problems worldwide, uropathogens use TCSs for adaptation, survival, and establishment of pathogenicity. For example, uropathogens can exploit TCSs to survive inside bladder epithelial cells, sense osmolar variations in urine, promote their ascension along the urinary tract or even produce lytic enzymes resulting in exfoliation of the urothelium. Despite the usefulness of studying the function of TCSs in in vitro experimental models, it is of primary necessity to study bacterial gene regulation also in the context of host niches, each displaying its own biological, chemical, and physical features. In light of this, the aim of this review is to provide a concise description of several bacterial TCSs, whose activity has been described in mouse models of UTI.

Neutrophil extracellular traps in urinary tract infection

Background

Urinary tract infections (UTI) are common types of bacterial infection in children. UTI treatment is aimed to prevent complications including hypertension, proteinuria, and progression to chronic kidney disease. Activated neutrophils release chromatin-based structures associated with antimicrobial proteins called neutrophil extracellular traps (NETs). We aimed to describe the role of NET-associated markers in children with UTI as well as the role of NETs formation in a mouse model of UTI.

Materials and methods

Markers of NETs including extracellular DNA (ecDNA), myeloperoxidase (MPO) and cathelicidin were analyzed in children with febrile UTI caused by E. coli (n = 98, aged 0.3-1.3 years) and in healthy controls (n = 50, 0.5-5.2 years). Moreover, an acute experimental model of UTI was performed on PAD4 knock-out mice with diminished NETs formation (n = 18), and on wild-type mice (n = 15).

Results

Children with UTI had significantly higher urinary NETs markers including total ecDNA, nuclear DNA and mitochondrial DNA, altogether with MPO and cathelicidin. The concentrations of MPO and cathelicidin positively correlated with ecDNA (r = 0.53, p ≤ 0.001; r = 0.56, p ≤ 0.001, respectively) and the number of leukocytes in the urine (r = 0.29, p ≤ 0.05; r = 0.27, p ≤ 0.05, respectively). Moreover, urinary MPO was positively associated with cathelicidin (r = 0.61, p ≤ 0.001). In the experimental model, bacterial load in the bladder (20-fold) and kidneys (300-fold) was significantly higher in PAD4 knock-out mice than in wild-type mice.

Conclusion

Higher urinary NETs makers-ecDNA, MPO and cathelicidin and their correlation with leukocyturia in children with UTI confirmed our hypothesis about the association between NETs and UTI in children. Higher bacterial load in mice with diminished NETs formation suggests that NETs are not only a simple consequence of UTI, but might play a direct role in the prevention of pyelonephritis and other UTI complications.

Gut-derived low-grade endotoxaemia, atherothrombosis and cardiovascular disease

Systemic inflammation has been suggested to have a pivotal role in atherothrombosis, but the factors that trigger systemic inflammation have not been fully elucidated. Lipopolysaccharide (LPS) is a component of the membrane of Gram-negative bacteria present in the gut that can translocate into the systemic circulation, causing non-septic, low-grade endotoxaemia. Gut dysbiosis is a major determinant of low-grade endotoxaemia via dysfunction of the intestinal barrier scaffold, which is a prerequisite for LPS translocation into the systemic circulation. Experimental studies have demonstrated that LPS is present in atherosclerotic arteries but not in normal arteries. In atherosclerotic plaques, LPS promotes a pro-inflammatory status that can lead to plaque instability and thrombus formation. Low-grade endotoxaemia affects several cell types, including leukocytes, platelets and endothelial cells, leading to inflammation and clot formation. Low-grade endotoxaemia has been described in patients at risk of or with overt cardiovascular disease, in whom low-grade endotoxaemia was associated with atherosclerotic burden and its clinical sequelae. In this Review, we describe the mechanisms favouring the development of low-grade endotoxaemia, focusing on gut dysbiosis and changes in gut permeability; the plausible biological mechanisms linking low-grade endotoxaemia and atherothrombosis; the clinical studies suggesting that low-grade endotoxaemia is a risk factor for cardiovascular events; and the potential therapeutic tools to improve gut permeability and eventually eliminate low-grade endotoxaemia.

Staphylococcus aureus ST1 promotes persistent urinary tract infection by highly expressing the urease

Staphylococcus aureus (SA) is a relatively uncommon cause of urinary tract infections (UTIs) in the general population. Although rare, S. aureus-induced UTIs are prone to potentially life-threatening invasive infections such as bacteremia. To investigate the molecular epidemiology, phenotypic characteristics, and pathophysiology of S. aureus-induced UTIs, we analyzed non-repetitive 4,405 S. aureus isolates collected from various clinical sources from 2008 to 2020 from a general hospital in Shanghai, China. Among these, 193 isolates (4.38%) were cultivated from the midstream urine specimens. Epidemiological analysis showed UTI-derived ST1 (UTI-ST1) and UTI-ST5 are the primary sequence types of UTI-SA. Furthermore, we randomly selected 10 isolates from each of the UTI-ST1, non-UTI-ST1 (nUTI-ST1), and UTI-ST5 groups to characterize their in vitro and in vivo phenotypes. The in vitro phenotypic assays revealed that UTI-ST1 exhibits an obvious decline in hemolysis of human red blood cells and increased biofilm and adhesion in the urea-supplemented medium, compared to the medium without urea, while UTI-ST5 and nUTI-ST1 did not show significant differences between the biofilm-forming and adhesion abilities. In addition, the UTI-ST1 displayed intense urease activities by highly expressing urease genes, indicating the potential role of urease in UTI-ST1 survival and persistence. Furthermore, in vitro virulence assays using the UTI-ST1 ureC mutant showed no significant difference in the hemolytic and biofilm-forming phenotypes in the presence or absence of urea in the tryptic soy broth (TSB) medium. The in vivo UTI model also showed that the CFU of the UTI-ST1 ureC mutant rapidly reduced during UTI pathogenesis 72 h post-infection, while UTI-ST1 and UTI-ST5 persisted in the urine of the infected mice. Furthermore, the phenotypes and the urease expression of UTI-ST1 were found to be potentially regulated by the Agr system with the change in environmental pH. In summary, our results provide important insights into the role of urease in S. aureus-induced UTI pathogenesis in promoting bacterial persistence in the nutrient-limiting urinary microenvironment.

Polysaccharides from Vaccaria segetalis seeds reduce urinary tract infections by inhibiting the adhesion and invasion abilities of uropathogenic Escherichia coli

The seeds of Vaccaria segetalis (Neck.) are from a traditional medicinal plant Garcke, also called Wang-Bu-Liu-Xing in China. According to the Chinese Pharmacopoeia, the seeds of V. segetalis can be used for treating urinary system diseases. This study was designed to investigate the underlying mechanism of VSP (polysaccharides from Vaccaria segetalis) against urinary tract infections caused by uropathogenic Escherichia coli (UPEC). Here, both in vitro and in vivo infection models were established with the UPEC strain CFT073. Bacterial adhesion and invasion into bladder epithelial cells were analyzed. We found that VSP reduced the adhesion of UPEC to the host by inhibiting the expression of bacterial hair follicle adhesion genes. VSP also reduced the invasion of UPEC by regulating the uroplakins and Toll-like receptors of host epithelial cells. In addition, the swarming motility and flagella-mediated motility genes flhC, flhD and Flic of UPEC were diminished after VSP intervention. Taken together, our findings reveal a possible mechanism by which VSP interferes with the adhesion and invasion of UPEC.

Antimicrobial Resistance and Virulence Factors of Proteus mirabilis Isolated from Dog with Chronic Otitis Externa

Otitis externa is among the most prevalent diseases in dogs. If the underlying cause is not addressed, bacterial reinfection becomes frequent, necessitating antibiotic administration for an extended period of time. Prolonged treatment promotes the emergence of antibiotic-resistant bacteria and increases the risk of their transmission from animals to humans. This study aimed to analyze the antibiotic resistance pattern of the emerging pathogen Proteus mirabilis to identify bacterial virulence and antibiotic selection. Samples were collected from randomly encountered dogs with chronic otitis externa. Thirty-two strains of P. mirabilis were isolated and identified, using MALDI-TOF. The Kirby-Bauer disk diffusion method was used to assess the antibiotic susceptibility of P. mirabilis to 11 antibiotics. The isolates (n = 32) were most resistant to cefazolin (75%), trimethoprim–sulfamethoxazole (72%), chloramphenicol (72%), amoxicillin–clavulanate (63%), ampicillin (59%), cefepime (56%), ciprofloxacin (53%), aztreonam (50%), ceftazidime avibactam (50%), gentamicin (22%), and amikacin (16%). Moreover, 75% of isolates were found to be multidrug-resistant bacteria. P. mirabilis was found to have a high resistance-pattern ratio. Although the exact cause is unknown, continuous antibiotic use is thought to be a major factor. We concluded that antibiotic use must be prudent and selective to prevent antibiotic resistance.

The Prevalence of Multidrug-Resistant Escherichia coli Producing ESBL among Male and Female Patients with Urinary Tract Infections in Riyadh Region, Saudi Arabia

The Escherichia coli that produces extended-spectrum lactamases (ESBL-E. coli) can develop resistance to many antibiotics. The control of ESBL-E. coli disorders is challenging due to their restricted therapeutic approaches, so this study aims to determine the prevalence and pattern of the antibiotic resistance of ESBL-E. coli among male and female patients with urinary tract infections in Riyadh, Saudi Arabia. During the period of 2019 to 2020 at King Fahd Medical City, Riyadh, 2250 urine samples from patients with urinary tract infections (UTIs) were collected, and microbial species were cultured and identified using standard biochemical techniques. A double-disc synergy test was used to identify ESBL-producing strains of E. coli, and an in vitro method and the clinical laboratory standard institute (CLSI) criteria were employed to determine the resistance of these strains to antimicrobial drugs. ESBL-E. coli was detected in 510 (33.49%) of the 1523 E. coli isolates, 67.27% of which were recovered from women and 33.7% of which were recovered from men. A total of 284 (55.69%) ESBL-E. coli isolates were found in patients under 50 years of age, and 226 (44.31%) were found in patients over 50 years of age. Nearly all the isolates of ESBL-E. coli were resistant to cephalosporins (ceftriaxone, cefotaxime, cefepime, cefuroxime, and cephalothin) and penicillin (ampicillin), whereas the majority of the isolates were sensitive to several carbapenems (imipenem, meropenem, and ertapenem), aminoglycosides (amikacin), and nitrofurantoins. The development of antibiotic resistance by ESBL-E. coli, the most frequent pathogen linked to urinary tract infections, plays a crucial role in determining which antibiotic therapy is appropriate.

An Iterative Approach Guides Discovery of the FabI Inhibitor Fabimycin, a Late-Stage Antibiotic Candidate with In Vivo Efficacy against Drug-Resistant Gram-Negative Infections

Genomic studies and experiments with permeability-deficient strains have revealed a variety of biological targets that can be engaged to kill Gram-negative bacteria. However, the formidable outer membrane and promiscuous efflux pumps of these pathogens prevent many candidate antibiotics from reaching these targets. One such promising target is the enzyme FabI, which catalyzes the rate-determining step in bacterial fatty acid biosynthesis. Notably, FabI inhibitors have advanced to clinical trials for Staphylococcus aureus infections but not for infections caused by Gram-negative bacteria. Here, we synthesize a suite of FabI inhibitors whose structures fit permeation rules for Gram-negative bacteria and leverage activity against a challenging panel of Gram-negative clinical isolates as a filter for advancement. The compound to emerge, called fabimycin, has impressive activity against >200 clinical isolates of Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii, and does not kill commensal bacteria. X-ray structures of fabimycin in complex with FabI provide molecular insights into the inhibition. Fabimycin demonstrates activity in multiple mouse models of infection caused by Gram-negative bacteria, including a challenging urinary tract infection model. Fabimycin has translational promise, and its discovery provides additional evidence that antibiotics can be systematically modified to accumulate in Gram-negative bacteria and kill these problematic pathogens.

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.

The role of urease in the acid stress response and fimbriae expression in Klebsiella pneumoniae CG43

BACKGROUND/PURPOSE

Two urease operons were identified in Klebsiella pneumoniae CG43, ure-1 and ure-2. This study investigates whether a differential regulation of the expression of ure-1 and ure-2 exists and how urease activity influences the acid stress response and expression of type 1 and type 3 fimbriae.

METHODS

The ureA1 and ureA2 gene specific deletion mutants were constructed. Promoter activity was assessed using a LacZ reporter system. The sensitivity to acid stress was determined by assessing the survival after pH 2.5 treatment. The influence on type 1 and type 3 fimbriae expression was assessed using western blotting and mannose-sensitive yeast agglutination and biofilm formation assay, respectively.

RESULTS

Bacterial growth analysis in mM9-U or modified Stuart broth revealed that ure-1 was the principal urease system, and ure-2 had a negative effect on ure-1 activity. Deletion of the fur or nac gene had no apparent effect on the activity of P_ure1, P_ure2-1, and P_ure2-2. The P_ure2-2 activity was enhanced by deletion of the hns gene. ureA1 deletion increased acid stress sensitivity, whereas the deleting effect of ureA2 was notable without hns. Deletion of ureA1 or ureA2 significantly induced the expression of type 1 fimbriae but decreased MrkA production and biofilm formation.

CONCLUSION

ure-1 is the primary expression system in K. pneumoniae CG43, while ure-2 is active in the absence of hns. Impairment of urease activity increases the sensitivity to acid stress, and the accumulation of urea induces the expression of type 1 fimbriae but represses type 3 fimbriae expression.

Dendrobium officinale polysaccharides attenuate uropathogenic Escherichia coli (UPEC)-induced pyroptosis in macrophage cells

Urinary tract infections (UTI) are recognized as one of the most common infectious diseases worldwide, and uropathogenic Escherichia coli (UPEC) is the main causative agent of UTI. Dendrobium officinale polysaccharides (DOPs), the main effective ingredient in Dendrobium officinale, have been reported to possess an anti-inflammatory role. Whether DOPs can attenuate the inflammatory injury (pyroptosis) induced by UPEC remains unknown. The present study aimed to assess the protective effect and potential mechanism of DOPs in UPEC-induced pyroptosis. Cell viability of THP-1 differentiated macrophage cells with DOPs was determined using MTT assay. Pyroptosis by UPEC in macrophage cells with or not DOPs pre-treatment was evaluated with flow cytometry analysis, lactate dehydrogenase (LDH) assay, and proinflammatory cytokines secretion. Expression level of key proteins in the NLRP3/Caspase-1/GSDMD pyroptotic pathway was analyzed with western blot. Furthermore the effect of DOPs on ROS activation was investigated. Results indicated that DOPs attenuated UPEC-induced cell damage in macrophage cells, inhibited the activation of NLRP3 mediated inflammasome, subsequently decreased induction and activation of caspase-1/GSDMD, and reduced the secretion of pro-inflammatory cytokine (IL-1β et al.). Moreover, pretreatment with DOPs significantly reduces ROS production, an important/putative pyroptosis stimulus signal. These results suggested that DOPs successfully mitigate UPEC-promoted pyroptosis in macrophage cells. The protective effects of DOPs are associated with the inhibition of the NLRP3/Caspase-1/GSDMD pathway and ROS signal activation.

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.

Phytochemicals and Nano-Phytopharmaceuticals Use in Skin, Urogenital and Locomotor Disorders: Are We There?

Nanomedicines emerged from nanotechnology and have been introduced to bring advancements in treating multiple diseases. Nano-phytomedicines are synthesized from active phytoconstituents or plant extracts. Advancements in nanotechnology also help in the diagnosis, monitoring, control, and prevention of various diseases. The field of nanomedicine and the improvements of nanoparticles has been of keen interest in multiple industries, including pharmaceutics, diagnostics, electronics, communications, and cosmetics. In herbal medicines, these nanoparticles have several attractive properties that have brought them to the forefront in searching for novel drug delivery systems by enhancing efficacy, bioavailability, and target specificity. The current review investigated various therapeutic applications of different nano-phytopharmaceuticals in locomotor, dermal, reproductive, and urinary tract disorders to enhance bioavailability and efficacy of phytochemicals and herbal extracts in preclinical and in vitro studies. There is a lack of clinical and extensive preclinical studies. The research in this field is expanding but strong evidence on the efficacy of these nano-phytopharmaceuticals for human use is still limited. The long-term efficacy and safety of nano-phytopharmaceuticals must be ensured with priority before these materials emerge as common human therapeutics. Overall, this review provides up-to-date information on related contemporary research on nano-phytopharmaceuticals and nano-extracts in the fields of dermatological, urogenital, and locomotor disorders.

Tissue Immunity in the Bladder

The bladder is a major component of the urinary tract, an organ system that expels metabolic waste and excess water, which necessitates proximity to the external environment and its pathogens. It also houses a commensal microbiome. Therefore, its tissue immunity must resist pathogen invasion while maintaining tolerance to commensals. Bacterial infection of the bladder is common, with half of women globally experiencing one or more episodes of cystitis in their lifetime. Despite this, our knowledge of bladder immunity, particularly in humans, is incomplete. Here we consider the current view of tissue immunity in the bladder, with a focus on defense against infection. The urothelium has robust immune functionality, and its defensive capabilities are supported by resident immune cells, including macrophages, dendritic cells, natural killer cells, and γδ T cells. We discuss each in turn and consider why adaptive immune responses are often ineffective in preventing recurrent infection, as well as areas of priority for future research.

Bladder epithelial cell phosphate transporter inhibition protects mice against uropathogenic Escherichia coli infection

Urinary tract infections are predominantly caused by uropathogenic Escherichia coli (UPEC). UPEC infects bladder epithelial cells (BECs) via fusiform vesicles, escapes into the cytosol to evade exocytosis, and establishes intracellular bacterial communities (IBCs) for the next round of infection. The UPEC vesicle escape mechanism remains unclear. Here we show that UPEC senses host immune responses and initiates escape by upregulating a key phospholipase. The UPEC phospholipase PldA disrupts the vesicle membrane, and pldA expression is activated by phosphate reduction in vesicles. The host phosphate transporter PIT1 is located on the fusiform vesicle membrane, transporting phosphate into the cytosol. UPEC infection upregulates PIT1 via nuclear factor κB (NF-κB), resulting in phosphate reduction. Silencing PIT1 blocks UPEC vesicle escape in BECs, inhibits IBC formation in mouse bladders, and protects mice from UPEC infection. Our results shed light on pathogenic bacteria responding to intracellular phosphate shortage and tackling host defense and provide insights for development of new therapeutic agents to treat UPEC infection.

One-step surface modification strategy with composition-tunable microgels: From bactericidal surface to cell-friendly surface

As modifiers for biomaterial surfaces, soft colloidal particles not only have good film-forming properties, but can also contribute to the function of the biomaterial via their chemical and biological properties. This general approach has proven effective for surface modification, but little is known about methods to control the properties of the colloidal particles to regulate film formation and biological function. In this work, we prepared poly (N-isopropylacrylamide) microgels (ZQP) containing both a zwitterionic component (Z) to provide anti-fouling functionality, and a quaternary ammonium salt (Q) to give bactericidal functionality. Fine-tuning of the Z and Q contents allowed the preparation of microgels over a range of particle size, size distribution, charge, and film-forming capability. The films showed anti-adhesion and contact-killing properties versus Escherichia coli (E. Coli), depending on the chemical composition. They also showed excellent cytocompatibility relative to L929 cells. A variety of microgel-coated substrates (silicon wafer, PDMS, PU, PVC) showed long-term anti-bacterial activity and resistance to chemical and mechanical treatments. It is concluded that this approach allows the preparation of effective bactericidal, cytocompatible surfaces. The properties can be fine-tuned by regulation of the microgel composition, and the method is applicable universally, i.e., independent of substrate.

The C5a/C5aR1 Axis Contributes to the Pathogenesis of Acute Cystitis Through Enhancement of Adhesion and Colonization of Uropathogenic E. coli

Our previous work using a murine model of pyelonephritis demonstrated that the C5a/C5aR1 axis plays a pathogenic role in acute kidney infection. In this study, we report that the C5a/C5aR1 axis also plays a pathogenic role in acute bladder infection. C5aR1-deficient mice had reduced bladder bacterial load and attenuated bladder tissue injury, which is associated with reduced expression of terminal α-mannosyl residues (Man) (a potential ligand for type 1 fimbriae of E. coli) at the luminal surface of the bladder epithelium and reduced early bacterial colonization of the bladder. In vitro, C5a stimulation enhanced mannose expression in and facilitated bacterial adhesion/colonization to human bladder epithelial cells. C5a stimulation also upregulated the activation of ERK1/2 and NF-κB signaling and gene expression of proinflammatory cytokines (i.e., Il6, Il1b, Cxcl1, Ccl2) in the epithelial cells, which could drive pro-inflammatory responses leading to tissue injury. Administration of the C5aR1 antagonist effectively reduced bladder bacterial load and tissue injury. Thus, our findings demonstrate a previously unknown pathogenic role for the C5a/C5aR1 axis in bladder infection and suggest that the C5a/C5aR1 axis-mediated upregulation of Man expression, enhancement of bacterial adhesion/colonization, and excessive inflammatory responses contribute to acute bladder infection. These findings improve our understanding of the pathogenesis of bladder infection with therapeutic implications for UTI.

Characterization of Uropathogenic Escherichia coli Reveals Hybrid Isolates of Uropathogenic and Diarrheagenic (UPEC/DEC) E. coli

(1) Background: Pathogenic Escherichia coli are divided into two groups: diarrheagenic (DEC) and extraintestinal pathogenic (ExPEC) E. coli. ExPEC causing urinary tract infections (UTIs) are termed uropathogenic E. coli (UPEC) and are the most common cause of UTIs worldwide. (2) Methods: Here, we characterized 112 UPEC in terms of phylogroup, serotype, the presence of virulence factor-encoding genes, and antimicrobial resistance. (3) Results: The majority of the isolates were assigned into the phylogroup B2 (41.07%), and the serogroups O6 (12.5%) and O25 (8.9%) were the most frequent. Five hybrid UPEC (4.5%), with markers from two DEC pathotypes, i.e., atypical enteropathogenic (aEPEC) and enteroaggregative (EAEC) E. coli, were identified, and designated UPEC/aEPEC (one isolate) and UPEC/EAEC (four isolates), respectively. Three UPEC/EAEC harbored genes from the pap operon, and the UPEC/aEPEC carried ibeA. The highest resistance rates were observed for ampicillin (46.4%) and trimethoprim/sulfamethoxazole (34.8%), while 99.1% of the isolates were susceptible to nitrofurantoin and/or fosfomycin. Moreover, 9.8% of the isolates were identified as Extended Spectrum β-Lactamase producers, including one hybrid UPEC/EAEC. (4) Conclusion: Our data reinforce that hybrid UPEC/DEC are circulating in the city of Botucatu, Brazil, as uropathogens. However, how and whether these combinations of genes influence their pathogenicity is a question that remains to be elucidated.