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

Synergistic Effects of Pyrrosia lingua Caffeoylquinic Acid Compounds with Levofloxacin Against Uropathogenic Escherichia coli: Insights from Molecular Dynamics Simulations, Antibiofilm, and Antimicrobial Assessments

Urinary tract infections (UTIs), primarily caused by uropathogenic Escherichia coli (UPEC), have high morbidity and recurrence rates. Resistance to levofloxacin hydrochloride (LEV), a commonly used treatment for UTIs, is increasingly problematic, exacerbated by biofilm formation mediated by interactions between cyclic di-GMP (c-di-GMP or CDG) and YcgR. In this study, we identified three caffeoylquinic acid compounds from Pyrrosia lingua-chlorogenic acid (CGA), sibiricose A5 (Si-A5), and 3-O-caffeoylquinic acid methyl ester (CAM)-that target YcgR through molecular docking. Biological assays revealed that combining these compounds with levofloxacin hydrochloride significantly enhanced antibacterial activity against standard UPEC strains in a concentration-dependent manner and clinically isolated UPEC strains. Notably, chlorogenic acid and sibiricose A5, when used with levofloxacin hydrochloride, enhanced intracellular c-di-GMP levels and swimming motility, significantly reduced YcgR gene expression, and effectively inhibited biofilm formation of UPEC at multiple time points. Additionally, molecular dynamics simulations elucidated the strong binding of these compounds to YcgR, underscoring the critical roles of residues, such as Arg118 and Asp145. This research serves as a foundation for tackling antibiotic resistance and developing innovative therapeutics for UTIs.

Effects of Heat-Killed Probiotic Strains on Biofilm Formation, Transcription of Virulence-Associated Genes, and Prevention of UTIs in Mice

Urinary tract infections (UTIs) pose a substantial healthcare challenge, exacerbated by the biofilm-forming abilities and antibiotic resistance of uropathogens. This study investigated the inhibition of biofilm formation (anti-biofilm) and dispersion of pre-established biofilm properties of 18 heat-killed probiotics and their supernatants against four antibiotic-resistant uropathogens: UPEC, Klebsiella pneumoniae (KP), Methicillin-resistant Escherichia coli (MREC), and Methicillin-resistant Staphylococcus pseudintermedius (MRSP). Supernatants from 14 probiotic strains significantly (P < 0.001) inhibited UPEC biofilm formation, reducing it by 20-80%, and also showed promise in removing existing biofilms by 10-60% (P < 0.001). Eight strains significantly (P < 0.05 to < 0.001) inhibited MREC biofilm formation, with four strains achieving 50-80% dispersion. Seventeen strains of heat-killed probiotics directly inhibited UPEC biofilm formation by 10-60% (P < 0.05 to < 0.001), but were less effective against MREC and MRSP (10-50% reduction; P < 0.05 to < 0.001) and had limited impact on KP (10% reduction; P < 0.05 to < 0.001). Notably, heat-killed probiotic like LGA, LGC, LGD, TP-8, and TP-4 showed the most significant inhibitory and dispersion of biofilm activity. RT-qPCR analysis further revealed these inactivated probiotics downregulated genes associated with pili and biofilm formation (fimA, csgA) and upregulated genes linked to quorum sensing (luxS, qseBC, sdiA). Therefore, these findings suggest that paraprobiotic treatment could inhibit the formation of pili and biofilms and promote biofilm dispersion. In an animal model, mice given paraprobiotic formulations I (16 strains) and II (a specific mixture) for 2 weeks showed reduced urinary bacterial load (P < 0.05). Paraprobiotic I notably reduced morbidity from bacteriuria (> 105 CFU/ml) by 5 to 30% within the first 5 days post-infection compared to placebo. These findings highlight the potential of specific heat-killed probiotics in combating biofilms and preventing UTIs.

Mimicking Urinary Tract Infections Caused by Uropathogenic Escherichia coli Using a Human Three-Dimensional Tissue Engineering Model

Uropathogenic Escherichia coli are the main causal agent of urinary tract infections. These diseases can affect more than half of women during their lifetime. Moreover, recurrent urinary tract infections can affect up to 30% of patients, leading to higher social and economic costs for the community. No efficient treatment against the recurrent form of the disease has been discovered. Due to the low average rate of successful translation from 2D cell culture and in vivo animal models into clinical trials, new models that mimic pathologies, such as those produced by tissue engineering, are needed. A model of human-derived 3D bladder mucosa was produced by tissue engineering techniques using collagen gels and organ-specific primary human stromal and epithelial cell populations. This model was used to mimic the different steps of a urinary tract infection: adhesion, invasion, intracellular bacterial community and quiescent intracellular reservoir formation and, finally, bacteria resurgence after umbrella cell exfoliation through chitosan exposure to mimic the recurrent infection. The uropathogenic strain UTI-89-GFP was used as infectious bacteria and BL-21-GFP strain as a control. Our model is unique and is the first step toward mimicking the different phases of a UTI in a human context.

Advances in experimental bladder models: bridging the gap between in vitro and in vivo approaches for investigating urinary tract infections

Urinary tract infections (UTIs) pose a substantial burden on global healthcare systems. When unraveling the complex pathophysiology of UTIs, bladder models are used to understand complex and multifaceted interactions between different components within the system. This review aimed to bridge the gap between in vitro and in vivo experimental bladder models towards UTI research. We reviewed clinical, animal, and analytical studies and patents from 1959 to the end of 2023. Both in vivo and in vitro models offer unique benefits and drawbacks in understanding UTIs. In vitro models provide controlled environments for studying specific aspects of UTI biology and testing potential treatments, while in vivo models offer insights into how UTIs manifest and progress within living organisms. Thus, both types of models are leading to the development of more effective diagnostic tools and therapeutic interventions against UTIs. Moreover, advanced methodologies involving three-dimensional bladder organoids have also been used to study bladder biology, model bladder-related disorders, and explore new treatments for bladder cancers, UTIs, and urinary incontinence. Narrowing the distance between fundamental scientific research and practical medical applications, these pioneering models hold the key to unlocking new avenues for the development of personalized diagnostics, precision medicine, and ultimately, the alleviation of UTI-related morbidity worldwide.

Organoids and organ-on-chip technology for investigating host-microorganism interactions

Recent advances in organoid and organ-on-chip (OoC) technologies offer an unprecedented level of tissue mimicry. These models can recapitulate the diversity of cellular composition, 3D organization, and mechanical stimulation. These approaches are intensively used to understand complex diseases. This review focuses on the latest advances in this field to study host-microorganism interactions.

Current state and novel outlook on prevention and treatment of rising antibiotic resistance in urinary tract infections

Antibiotic-resistant bacteria are currently an important public health concern posing a serious threat due to their resistance to the current arsenal of antibiotics. Uropathogens Escherichia coli (UPEC), Proteus mirabilis, Klebsiella pneumoniae and Enterococcus faecalis, antibiotic-resistant gram-negative bacteria, cause serious cases of prolonged UTIs, increasing healthcare costs and potentially even leading to the death of an affected patient. This review discusses current knowledge about the increasing resistance to currently recommended antibiotics for UTI therapy, as well as novel therapeutic options. Traditional antibiotics are still a part of the therapy guidelines for UTIs, although they are often not effective and have serious side effects. Hence, novel drugs are being developed, such as combinations of β-lactam antibiotics with cephalosporins and carbapenems. Siderophoric cephalosporins, such as cefiderocol, have shown potential in the treatment of individuals with significant gram-negative bacterial infections, as well as aminoglycosides, fluoroquinolones and tetracyclines that are also undergoing clinical trials. The use of cranberry and probiotics is another potential curative and preventive method that has shown antimicrobial and anti-inflammatory effects. However, further studies are needed to assess the efficacy and safety of probiotics containing cranberry extract for UTI prevention and treatment. An emerging novel approach for UTI treatment is the use of immuno-prophylactic vaccines, as well as different nanotechnology solutions such as nanoparticles (NP). NP have the potential to be used as delivery systems for drugs to specific targets. Furthermore, nanotechnology could enable the development of nano antibiotics with improved features by the application of different NPs in their structure, such as gold and copper NPs. However, further high-quality research is required for the synthesis and testing of these novel molecules, such as safety evaluation and pharmacovigilance.

Plant phenolics inhibit focal adhesion kinase and suppress host cell invasion by uropathogenic Escherichia coli

Traditional folk treatments for the prevention and management of urinary tract infections (UTIs) and other infectious diseases often include plants and plant extracts that are rich in phenolic compounds. These have been ascribed a variety of activities, including inhibition of bacterial interactions with host cells. Here, we tested a panel of four well-studied phenolic compounds-caffeic acid phenethyl ester (CAPE), resveratrol, catechin, and epigallocatechin gallate-for the effects on host cell adherence and invasion by uropathogenic Escherichia coli (UPEC). These bacteria, which are the leading cause of UTIs, can bind and subsequently invade bladder epithelial cells via an actin-dependent process. Intracellular UPEC reservoirs within the bladder are often protected from antibiotics and host defenses and likely contribute to the development of chronic and recurrent infections. In cell culture-based assays, only resveratrol had a notable negative effect on UPEC adherence to bladder cells. However, both CAPE and resveratrol significantly inhibited UPEC entry into the host cells, coordinate with attenuated phosphorylation of the host actin regulator Focal Adhesion Kinase (FAK or PTK2) and marked increases in the numbers of focal adhesion structures. We further show that the intravesical delivery of resveratrol inhibits UPEC infiltration of the bladder mucosa in a murine UTI model and that resveratrol and CAPE can disrupt the ability of other invasive pathogens to enter host cells. Together, these results highlight the therapeutic potential of molecules like CAPE and resveratrol, which could be used to augment antibiotic treatments by restricting pathogen access to protective intracellular niches.IMPORTANCEUrinary tract infections (UTIs) are exceptionally common and increasingly difficult to treat due to the ongoing rise and spread of antibiotic-resistant pathogens. Furthermore, the primary cause of UTIs, uropathogenic Escherichia coli (UPEC), can avoid antibiotic exposure and many host defenses by invading the epithelial cells that line the bladder surface. Here, we identified two plant-derived phenolic compounds that disrupt activation of the host machinery needed for UPEC entry into bladder cells. One of these compounds, resveratrol, effectively inhibited UPEC invasion of the bladder mucosa in a mouse UTI model, and both phenolic compounds significantly reduced host cell entry by other invasive pathogens. These findings suggest that select phenolic compounds could be used to supplement existing antibacterial therapeutics by denying uropathogens shelter within host cells and tissues and help explain some of the benefits attributed to traditional plant-based medicines.

Antimicrobial susceptibility patterns of urinary tract infections causing bacterial isolates and associated risk factors among HIV patients in Tigray, Northern Ethiopia

BACKGROUND

Urinary tract infections, a prevalent global infectious disease, are clinical issues not well studied in HIV-positive individuals. UTIs have become a global drug resistance issue, but the prevalence and antibiotic susceptibility patterns of UTI-causing bacteria among HIV patients in Tigray, Ethiopia, are poorly understood. This study aims to identify the prevalence of UTI-causing bacteria, their antibiotic susceptibility patterns, and associated risk factors in HIV patients attending ART clinics at Mekelle General Hospital and Ayder Comprehensive Specialized Hospital in Tigray, Northern Ethiopia.

METHOD

Clean-catch midstream urine samples (10-15 mL) were collected from HIV patients who are attending ART clinics at Mekelle General Hospital and Ayder Comprehensive Specialized Hospital. Samples were analyzed based on standard microbiological protocols using cysteine-lactose electrolyte deficient (CLED) agar. Pure colonies of bacterial isolates were obtained by sub-culturing into Mac-Conkey, Manitol Salt agar and blood agar plates. The bacterial isolates were then identified using macroscopic, microscopic, biochemical, and Gram staining methods. Gram-negative bacteria were identified using biochemical tests like triple sugar iron agar, Simon's citrate agar, lysine iron agar, urea, motility test, and indol test, whereas Gram-positive isolates were identified using catalase and coagulase tests. The Kirby-Bauer disk diffusion technique was used to analyze the antimicrobial susceptibility pattern of bacterial isolates. Data was analyzed using SPSS version 25.0.

RESULTS

Among the 224 patients, 28 (12.5%) of them had been infected by UTIs-causing bacteria. E. coli was the dominant bacterium (16 (57%)) followed by K. pneumoniae (4 (14%)), and S. aureus (3 (11%)). Of the total bacterial isolates, 22 (78.6%) of them developed multi-drug resistance. All Gram-positive (100%) and 75% of Gram-negative bacterial isolates were found to be resistant to two or more drugs. Patients with a history of UTIs, and with CD4 count < 200 cells/ mm3, were more likely to have significant bacteriuria. Compared to male patients, female patients were more affected by the UTIs-causing bacteria. More than 93% of the UTIs-causing bacterial isolates were susceptible to nitrofurantoin, ceftriaxone, ciprofloxacin, and gentamycin; whereas they are highly resistant to ampicillin (96%), cotrimoxazole (82%) and tetracycline (71%).

CONCLUSIONS

Most of the bacterial isolates were highly resistant to ampicillin, cotrimoxazole, and tetracycline. Female patients were more affected by the UTIs causing bacteria. The highest prevalence (12.5%) of UTIs in HIV patients needs special attention for better management and monitoring. Previous UTI history and immune suppression are predictors of UTIs, highlighting the need for intervention measures involving molecular studies to identify resistant bacteria genes and promote patient immune reconstitution.

TusDCB, a sulfur transferase complex involved in tRNA modification, contributes to UPEC pathogenicity

tRNA modifications play a crucial role in ensuring accurate codon recognition and optimizing translation levels. While the significance of these modifications in eukaryotic cells for maintaining cellular homeostasis and physiological functions is well-established, their physiological roles in bacterial cells, particularly in pathogenesis, remain relatively unexplored. The TusDCB protein complex, conserved in γ-proteobacteria like Escherichia coli, is involved in sulfur modification of specific tRNAs. This study focused on the role of TusDCB in the virulence of uropathogenic E. coli (UPEC), a bacterium causing urinary tract infections. The findings indicate that TusDCB is essential for optimal production of UPEC's virulence factors, including type 1 fimbriae and flagellum, impacting the bacterium's ability to aggregate in bladder epithelial cells. Deletion of tusDCB resulted in decreased virulence against urinary tract infection mice. Moreover, mutant TusDCB lacking sulfur transfer activity and tusE- and mnmA mutants revealed the indispensability of TusDCB's sulfur transfer activity for UPEC pathogenicity. The study extends its relevance to highly pathogenic, multidrug-resistant strains, where tusDCB deletion reduced virulence-associated bacterial aggregation. These insights not only deepen our understanding of the interplay between tRNA sulfur modification and bacterial pathogenesis but also highlight TusDCB as a potential therapeutic target against UPEC strains resistant to conventional antimicrobial agents.

Uropathogenic Escherichia coli infection: innate immune disorder, bladder damage, and Tailin Fang II

Background

Uropathogenic Escherichia coli (UPEC) activates innate immune response upon invading the urinary tract, whereas UPEC can also enter bladder epithelial cells (BECs) through interactions with fusiform vesicles on cell surfaces and subsequently escape from the vesicles into the cytoplasm to establish intracellular bacterial communities, finally evading the host immune system and leading to recurrent urinary tract infection (RUTI). Tailin Fang II (TLF-II) is a Chinese herbal formulation composed of botanicals that has been clinically proven to be effective in treating urinary tract infection (UTI). However, the underlying therapeutic mechanisms remain poorly understood.

Methods

Network pharmacology analysis of TLF-II was conducted. Female Balb/C mice were transurethrally inoculated with UPEC CFT073 strain to establish the UTI mouse model. Levofloxacin was used as a positive control. Mice were randomly divided into four groups: negative control, UTI, TLF-II, and levofloxacin. Histopathological changes in bladder tissues were assessed by evaluating the bladder organ index and performing hematoxylin-eosin staining. The bacterial load in the bladder tissue and urine sample of mice was quantified. Activation of the TLR4-NF-κB pathway was investigated through immunohistochemistry and western blotting. The urinary levels of interleukin (IL)-1β and IL-6 and urine leukocyte counts were monitored. We also determined the protein expressions of markers associated with fusiform vesicles, Rab27b and Galectin-3, and levels of the phosphate transporter protein SLC20A1. Subsequently, the co-localization of Rab27b and SLC20A1 with CFT073 was examined using confocal fluorescence microscopy.

Results

Data of network pharmacology analysis suggested that TLF-II could against UTI through multiple targets and pathways associated with innate immunity and inflammation. Additionally, TLF-II significantly attenuated UPEC-induced bladder injury and reduced the bladder bacterial load. Meanwhile, TLF-II inhibited the expression of TLR4 and NF-κB on BECs and decreased the urine levels of IL-1β and IL-6 and urine leukocyte counts. TLF-II reduced SLC20A1 and Galectin-3 expressions and increased Rab27b expression. The co-localization of SLC20A1 and Rab27b with CFT073 was significantly reduced in the TLF-II group.

Conclusion

Collectively, innate immunity and bacterial escape from fusiform vesicles play important roles in UPEC-induced bladder infections. Our findings suggest that TLF-II combats UPEC-induced bladder infections by effectively mitigating bladder inflammation and preventing bacterial escape from fusiform vesicles into the cytoplasm. The findings suggest that TLF-II is a promising option for treating UTI and reducing its recurrence.

Investigating inhibitors of 1-deoxy-d-xylulose 5-phosphate synthase in a mouse model of UTI

The rising rate of antimicrobial resistance continues to threaten global public health. Further hastening antimicrobial resistance is the lack of new antibiotics against new targets. The bacterial enzyme, 1-deoxy-d-xylulose 5-phosphate synthase (DXPS), is thought to play important roles in central metabolism, including processes required for pathogen adaptation to fluctuating host environments. Thus, impairing DXPS function represents a possible new antibacterial strategy. We previously investigated a DXPS-dependent metabolic adaptation as a potential target in uropathogenic Escherichia coli (UPEC) associated with urinary tract infection (UTI), using the DXPS-selective inhibitor butyl acetylphosphonate (BAP). However, investigations of DXPS inhibitors in vivo have not been conducted. The goal of the present study is to advance DXPS inhibitors as in vivo probes and assess the potential of inhibiting DXPS as a strategy to prevent UTI in vivo. We show that BAP was well-tolerated at high doses in mice and displayed a favorable pharmacokinetic profile for studies in a mouse model of UTI. Further, an alkyl acetylphosphonate prodrug (homopropargyl acetylphosphonate, pro-hpAP) was significantly more potent against UPEC in urine culture and exhibited good exposure in the urinary tract after systemic dosing. Prophylactic treatment with either BAP or pro-hpAP led to a partial protective effect against UTI, with the prodrug displaying improved efficacy compared to BAP. Overall, our results highlight the potential for DXPS inhibitors as in vivo probes and establish preliminary evidence that inhibiting DXPS impairs UPEC colonization in a mouse model of UTI.IMPORTANCENew antibiotics against new targets are needed to prevent an antimicrobial resistance crisis. Unfortunately, antibiotic discovery has slowed, and many newly FDA-approved antibiotics do not inhibit new targets. Alkyl acetylphosphonates (alkyl APs), which inhibit the enzyme 1-deoxy-d-xylulose 5-phosphate synthase (DXPS), represent a new possible class of compounds as there are no FDA-approved DXPS inhibitors. To our knowledge, this is the first study demonstrating the in vivo safety, pharmacokinetics, and efficacy of alkyl APs in a urinary tract infection mouse model.

Analyzing the correlation between quinolone-resistant Escherichia coli resistance rates and climate factors: A comprehensive analysis across 31 Chinese provinces

BACKGROUND

The increasing problem of bacterial resistance, particularly with quinolone-resistant Escherichia coli (QnR eco) poses a serious global health issue.

METHODS

We collected data on QnR eco resistance rates and detection frequencies from 2014 to 2021 via the China Antimicrobial Resistance Surveillance System, complemented by meteorological and socioeconomic data from the China Statistical Yearbook and the China Meteorological Data Service Centre (CMDC). Comprehensive nonparametric testing and multivariate regression models were used in the analysis.

RESULT

Our analysis revealed significant regional differences in QnR eco resistance and detection rates across China. Along the Hu Huanyong Line, resistance rates varied markedly: 49.35 in the northwest, 54.40 on the line, and 52.30 in the southeast (P = 0.001). Detection rates also showed significant geographical variation, with notable differences between regions (P < 0.001). Climate types influenced these rates, with significant variability observed across different climates (P < 0.001). Our predictive model for resistance rates, integrating climate and healthcare factors, explained 64.1% of the variance (adjusted R-squared = 0.641). For detection rates, the model accounted for 19.2% of the variance, highlighting the impact of environmental and healthcare influences.

CONCLUSION

The study found higher resistance rates in warmer, monsoon climates and areas with more public health facilities, but lower rates in cooler, mountainous, or continental climates with more rainfall. This highlights the strong impact of climate on antibiotic resistance. Meanwhile, the predictive model effectively forecasts these resistance rates using China's diverse climate data. This is crucial for public health strategies and helps policymakers and healthcare practitioners tailor their approaches to antibiotic resistance based on local environmental conditions. These insights emphasize the importance of considering regional climates in managing antibiotic resistance.

Animal models of Klebsiella pneumoniae mucosal infections

Klebsiella pneumoniae is among the most relevant pathogens worldwide, causing high morbidity and mortality, which is worsened by the increasing rates of antibiotic resistance. It is a constituent of the host microbiota of different mucosa, that can invade and cause infections in many different sites. The development of new treatments and prophylaxis against this pathogen rely on animal models to identify potential targets and evaluate the efficacy and possible side effects of therapeutic agents or vaccines. However, the validity of data generated is highly dependable on choosing models that can adequately reproduce the hallmarks of human diseases. The present review summarizes the current knowledge on animal models used to investigate K. pneumoniae infections, with a focus on mucosal sites. The advantages and limitations of each model are discussed and compared; the applications, extrapolations to human subjects and future modifications that can improve the current techniques are also presented. While mice are the most widely used species in K. pneumoniae animal studies, they present limitations such as the natural resistance to the pathogen and difficulties in reproducing the main steps of human mucosal infections. Other models, such as Drosophila melanogaster (fruit fly), Caenorhabditis elegans, Galleria mellonella and Danio rerio (zebrafish), contribute to understanding specific aspects of the infection process, such as bacterial lethality and colonization and innate immune system response, however, they but do not present the immunological complexity of mammals. In conclusion, the choice of the animal model of K. pneumoniae infection will depend mainly on the questions being addressed by the study, while a better understanding of the interplay between bacterial virulence factors and animal host responses will provide a deeper comprehension of the disease process and aid in the development of effective preventive/therapeutic strategies.

Clinical Characteristics of Uncomplicated Acute Pyelonephritis Caused by Escherichia coli and Klebsiella pneumoniae

INTRODUCTION

This study compared the clinical characteristics and antimicrobial susceptibility of uncomplicated acute pyelonephritis (APN) caused by Escherichia coli and Klebsiella pneumoniae.

METHODS

We retrospectively reviewed the medical records of patients with uncomplicated APNs caused by E. coli and K. pneumoniae admitted to Keimyung University Dongsan Hospital between February 2014 and December 2021.

RESULTS

We enrolled 497 patients (372 with E. coli infection, 125 with K. pneumoniae infection). Male, healthcare-associated infection, solid tumors, liver cirrhosis, chronic renal disease, solid organ transplantation, and antibiotic usage within the last 3 months were more strongly associated with K. pneumoniae uncomplicated APNs than with E. coli. Bacteremia and fever occurred more frequently in E. coli uncomplicated APNs. Antimicrobial resistance rates to piperacillin/tazobactam and carbapenem were higher in K. pneumoniae. Antimicrobial resistance rates to aztreonam and ciprofloxacin were lower in K. pneumoniae. Thirty-day mortality was more observed in K. pneumoniae group in univariate analysis, but this difference was not observed after adjustment. Male sex, ultimately fatal disease in McCabe, and prior antibiotic use within 3 months were more associated with K. pneumoniae.

CONCLUSIONS

Male, underlying diseases, and prior antibiotic use was more associated with K. pneumoniae. Further study will be needed that microbiome of each situation and the related with the distribution of the strains.

Minimum Information for Conducting and Reporting In Vitro Intracellular Infection Assays

Bacterial pathogens are constantly evolving to outsmart the host immune system and antibiotics developed to eradicate them. One key strategy involves the ability of bacteria to survive and replicate within host cells, thereby causing intracellular infections. To address this unmet clinical need, researchers are adopting new approaches, such as the development of novel molecules that can penetrate host cells, thus exerting their antimicrobial activity intracellularly, or repurposing existing antibiotics using nanocarriers (i.e., nanoantibiotics) for site-specific delivery. However, inconsistency in information reported across published studies makes it challenging for scientific comparison and judgment of experiments for future direction by researchers. Together with the lack of reproducibility of experiments, these inconsistencies limit the translation of experimental results beyond pre-clinical evaluation. Minimum information guidelines have been instrumental in addressing such challenges in other fields of biomedical research. Guidelines and recommendations provided herein have been designed for researchers as essential parameters to be disclosed when publishing their methodology and results, divided into four main categories: (i) experimental design, (ii) establishing an in vitro model, (iii) assessment of efficacy of novel therapeutics, and (iv) statistical assessment. These guidelines have been designed with the intention to improve the reproducibility and rigor of future studies while enabling quantitative comparisons of published studies, ultimately facilitating translation of emerging antimicrobial technologies into clinically viable therapies that safely and effectively treat intracellular infections.

Novel Antimicrobial Approaches to Combat Bacterial Biofilms Associated with Urinary Tract Infections

Urinary tract infections (UTIs) are prevalent bacterial infections in both community and healthcare settings. They account for approximately 40% of all bacterial infections and require around 15% of all antibiotic prescriptions. Although antibiotics have traditionally been used to treat UTIs for several decades, the significant increase in antibiotic resistance in recent years has made many previously effective treatments ineffective. Biofilm on medical equipment in healthcare settings creates a reservoir of pathogens that can easily be transmitted to patients. Urinary catheter infections are frequently observed in hospitals and are caused by microbes that form a biofilm after a catheter is inserted into the bladder. Managing infections caused by biofilms is challenging due to the emergence of antibiotic resistance. Biofilms enable pathogens to evade the host's innate immune defences, resulting in long-term persistence. The incidence of sepsis caused by UTIs that have spread to the bloodstream is increasing, and drug-resistant infections may be even more prevalent. While the availability of upcoming tests to identify the bacterial cause of infection and its resistance spectrum is critical, it alone will not solve the problem; innovative treatment approaches are also needed. This review analyses the main characteristics of biofilm formation and drug resistance in recurrent uropathogen-induced UTIs. The importance of innovative and alternative therapies for combatting biofilm-caused UTI is emphasised.

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.

Pre-operative factors associated with the development of distal ureteral stump syndrome after upper pole heminephrectomy

INTRODUCTION

For children with duplex systems and severe hydroureteronephrosis of the upper pole, heminephrectomy is one of many suitable treatments, particularly if there is no associated lower pole reflux. Distal ureteral stump syndrome (DSS) is a very difficult complication and manifests as stump empyema, urinary tract infection and/or vulvar discharge and can occur months to years later in 10-20 percent of patients. Secondary distal ureterectomy is an extremely difficult surgery due to inflammation and adhesions. To avoid DSS, distal ureterectomy at the time of heminephrectomy can be performed concurrently but carries a risk of lower pole ureter devascularization and injury. Current literature on DSS has shown associations with subtotal ureterectomy or long ureteral stumps. We hypothesized that there may be preoperative variables prior to heminephrectomy that are associated with the development of DSS.

OBJECTIVE

Identify pre-operative risk factors for the development of DSS in pediatric patients who underwent upper pole heminephrectomy for duplex kidneys.

STUDY METHODS

Retrospective analysis of pediatric patients who underwent upper pole heminephrectomy at single, academic institution from 1999 to 2021. Pre-operative patient age, gender, history, imaging, and lab results were extracted from patient charts to assess for factors that may predict the development of DSS. Patient groups with and without DSS were compared using Fischer's Exact Test.

RESULTS

Five (14%) of 36 patients developed DSS and required secondary distal ureterectomy at a median time of 22 months (IQR 6-27) after heminephrectomy. The presence of ureteral debris (80% of DSS) on preoperative ultrasound (p < 0.001), reflux into the upper pole (p = 0.005), and mucus discharge (100% of DSS) (p < 0.001) prior to surgery were found to be significantly associated with those who developed DSS, compared to those who did not. These three pre-operative factors had high specificity (97-100%) and negative predictive value (94-97%).

DISCUSSION

Substantial experience has shown that less than 20% of patients benefit from distal ureterectomy during upper heminephrectomy. Whether using an open or laparoscopic approach, selection of at-risk patients should lower operative time and avoid injury and devascularization of the lower pole ureter for most patients.

CONCLUSION

The presence or absence of ureteral debris, mucus discharge and/or upper pole reflux prior to heminephrectomy may be useful guides in selecting which patients would benefit from concurrent distal ureterectomy and conversely which patients may safely avoid the additional dissection.

Plant Phenolics Inhibit Focal Adhesion Kinase and Suppress Host Cell Invasion by Uropathogenic Escherichia coli

Traditional folk treatments for the prevention and management of urinary tract infections (UTIs) and other infectious diseases often include plants and plant extracts that are rich in phenolic and polyphenolic compounds. These have been ascribed a variety of activities, including inhibition of bacterial interactions with host cells. Here we tested a panel of four well-studied phenolic compounds - caffeic acid phenethyl ester (CAPE), resveratrol, catechin, and epigallocatechin gallate - for effects on host cell adherence and invasion by uropathogenic Escherichia coli (UPEC). These bacteria, which are the leading cause of UTIs, can bind and subsequently invade bladder epithelial cells via an actin-dependent process. Intracellular UPEC reservoirs within the bladder are often protected from antibiotics and host defenses, and likely contribute to the development of chronic and recurrent infections. Using cell culture-based assays, we found that only resveratrol had a notable negative effect on UPEC adherence to bladder cells. However, both CAPE and resveratrol significantly inhibited UPEC entry into the host cells, coordinate with attenuated phosphorylation of the host actin regulator Focal Adhesion Kinase (FAK, or PTK2) and marked increases in the numbers of focal adhesion structures. We further show that the intravesical delivery of resveratrol inhibits UPEC infiltration of the bladder mucosa in a murine UTI model, and that resveratrol and CAPE can disrupt the ability of other invasive pathogens to enter host cells. Together, these results highlight the therapeutic potential of molecules like CAPE and resveratrol, which could be used to augment antibiotic treatments by restricting pathogen access to protective intracellular niches.

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

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

Are Escherichia coli causing recurrent cystitis just ordinary Uropathogenic E. coli (UPEC) strains?

Specific determinants associated with Uropathogenic Escherichia coli (UPEC) causing recurrent cystitis are still poorly characterized. The aims of this study were (i) to describe genomic and phenotypic traits associated with recurrence using a large collection of recurrent and paired sporadic UPEC isolates, and (ii) to explore within-host genomic adaptation associated with recurrence using series of 2 to 5 sequential UPEC isolates. Whole genome comparative analyses between 24 recurrent cystitis isolates (RCIs) and 24 phylogenetically paired sporadic cystitis isolates (SCIs) suggested a lower prevalence of putative mobile genetic elements (MGE) in RCIs, such as plasmids and prophages. The intra-patient evolution of the 24 RCI series over time was characterized by SNP occurrence in genes involved in metabolism or membrane transport, and by plasmid loss in 5 out of the 24 RCI series. Genomic evolution occurred early in the course of recurrence, suggesting rapid adaptation to strong selection pressure in the urinary tract. However, RCIs did not exhibit specific virulence factor determinants and could not be distinguished from SCIs by their fitness, biofilm formation, or ability to invade HTB-9 bladder epithelial cells. Taken together, these results suggest a rapid but not convergent adaptation of RCIs that involves both strain- and host-specific characteristics.

Preclinical Evaluation of Nitroxide-Functionalised Ciprofloxacin as a Novel Antibiofilm Drug Hybrid for Urinary Tract Infections

Urinary tract infections (UTIs) are the second most common bacterial infection with high recurrence rates and can involve biofilm formation on patient catheters. Biofilms are inherently tolerant to antimicrobials, making them difficult to eradicate. Many antibiofilm agents alone do not have bactericidal activity; therefore, linking them to antibiotics is a promising antibiofilm strategy. However, many of these hybrid agents have not been tested in relevant preclinical settings, limiting their potential for clinical translation. Here, we evaluate a ciprofloxacin di-nitroxide hybrid (CDN11), previously reported to have antibiofilm activity against uropathogenic Escherichia coli (UPEC) strain UTI89 in vitro, as a potential UTI therapeutic using multiple preclinical models that reflect various aspects of UTI pathogenesis. We report improved in vitro activity over the parent drug ciprofloxacin against mature UTI89 biofilms formed inside polyethylene catheters. In bladder cell monolayers infected with UTI89, treatment with CDN11 afforded significant reduction in bacterial titers, including intracellular UPEC. Infected mouse bladders containing biofilm-like intracellular reservoirs of UPEC UTI89 showed decreased bacterial loads after ex vivo bladder treatment with CDN11. Activity for CDN11 was reported across different models of UTI, showcasing nitroxide-antibiotic hybridization as a promising antibiofilm approach. The pipeline we described here could be readily used in testing other new therapeutic compounds, fast-tracking the development of novel antibiofilm therapeutics.

Contribution of Antibiotic Susceptibility Testing and CH Typing Compared to Next-Generation Sequencing for the Diagnosis of Recurrent Urinary Tract Infections Due to Genetically Identical Escherichia coli Isolates: a Prospective Cohort Study of Cystitis in Women

Recurrent cystitis is a common disease in women, mainly due to uropathogenic Escherichia coli (UPEC). For decades, typing methods now considered obsolete suggested that relapse by the same clone is dominant over reinfection, most UPEC strains being otherwise fully susceptible to antibiotics. We aimed to update these data. Thanks to a prospective study over 17 months, we recruited 323 women with cystitis. Of these, 251 of them had sporadic infection and 72 had recurrence, with 2 to 9 episodes per patient for a total of 131 UPEC isolates and 145 UPEC pairs at patient level. Phylogroups B2 (52.4%) and D (14.1%) were overall dominant, as expected due to their particular urovirulence. CH typing identified 119 distinct profiles with no CH type particularly associated with recurrence. Relapse was attested by CH typing for only 30.6% (22 out of 72), with very diverse situations ranging from all episodes due to the same clone to alternating reinfections and relapses. Next-generation sequencing confirmed the clonality for all but two of the 145 UPEC pairs. Antibiotic resistance was common for recurrent cystitis isolates (only 25 [17.2%] out of 145 UPEC pairs were fully susceptible), allowing us to predict UPEC clonality. Indeed, antibiotic susceptibility profile matched CH typing for 104 (71.7%) pairs. Finally, we demonstrated a large genetic diversity among UPEC isolates responsible for cystitis in women, even in cases of recurrence for which reinfection appeared dominant over relapse. Recurrent cystitis appears to be a heterogeneous disease requiring tailored treatment and prevention. IMPORTANCE More than half of women will experience cystitis during their lifetime. Among these women, 25% will experience a second episode within the following 6 months. It is epidemiologically important to discriminate relapses from reinfections. Relapse identification relies on long and laborious methods and might influence treatment. Therefore, the designation of time- and cost-effective strategies for this goal is of particular interest. Our work suggests using CH typing and antibiotic susceptibility profiles to type Escherichia coli, the main uropathogen.

Emerging evidence-based innovative approaches to control catheter-associated urinary tract infection: a review

Healthcare settings have dramatically advanced the latest medical devices, such as urinary catheters (UC) for infection, prevention, and control (IPC). The continuous or intermittent flow of a warm and conducive (urine) medium in the medical device, the urinary catheter, promotes the formation of biofilms and encrustations, thereby leading to the incidence of CAUTI. Additionally, the absence of an innate immune host response in and around the lumen of the catheter reduces microbial phagocytosis and drug action. Hence, the review comprehensively overviews the challenges posed by CAUTI and associated risks in patients' morbidity and mortality. Also, detailed, up-to-date information on the various strategies that blended/tailored the surface properties of UC to have anti-fouling, biocidal, and anti-adhesive properties to provide an outlook on how they can be better managed with futuristic solutions.

Using evolutionary principles to make clinical decisions: a case series of urinary tract infections

The principles of evolutionary medicine have significant potential to be useful in a wide variety of clinical situations. Despite this, few demonstrations of clinical applications exist. To address this paucity, a case series applying evolutionary medicine principles to urinary tract infections, a common medical condition is presented. This series demonstrates how applying evolutionary medicine principles can be used to augment clinical decision-making.

Recent Advances in Pharmaceutical Approaches of Antimicrobial Agents for Selective Delivery in Various Administration Routes

Globally, the increase of pathogenic bacteria with antibiotic-resistant characteristics has become a critical challenge in medical treatment. The misuse of conventional antibiotics to treat an infectious disease often results in increased resistance and a scarcity of effective antimicrobials to be used in the future against the organisms. Here, we discuss the rise of antimicrobial resistance (AMR) and the need to combat it through the discovery of new synthetic or naturally occurring antibacterial compounds, as well as insights into the application of various drug delivery approaches delivered via various routes compared to conventional delivery systems. AMR-related infectious diseases are also discussed, as is the efficiency of various delivery systems. Future considerations in developing highly effective antimicrobial delivery devices to address antibiotic resistance are also presented here, especially on the smart delivery system of antibiotics.

Design and Development of Extracellular Matrix Protein-Based Microcapsules as Tools for Bacteria Investigation

The extracellular matrix (ECM) plays an immense role in the homeostasis of tissues and organs, can function as a barrier for infectious agents, but is also exploited by pathogens during infection. Therefore, the development of well-defined 3D ECM models in the form of microcapsules to elucidate the interactions between ECM components and pathogens in confinement and study disease infectivity is important, albeit challenging. Current limitations are mainly attributed to the lack of biocompatible methods for the production of protein-based microcapsules. Herein, hollow ECM-based microcapsules from laminin-111 or laminin-111/collagen IV are generated to investigate the behavior of organisms within confined 3D extracellular matrices. Microcapsules are created using water-in-oil emulsion droplets stabilized by block copolymer surfactants as templates for the charge-mediated attraction of laminin or laminin-collagen proteins to the droplets' inner periphery, allowing for the formation of modular ECM-based microcapsules with tunable biophysical and biochemical properties and organism encapsulation. The release of E. coli-laden ECM-based protein microcapsules into a physiological environment revealed differences in the dynamic behavior of E. coli depending on the constitution of the surrounding ECM protein matrix. The developed ECM-based protein microcapsules have the potential to be implemented in several biomedical applications, including the design of in vitro infection models.

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.

Antibiotic use during coronavirus disease 2019 intensive care unit shape multidrug resistance bacteriuria: A Swedish longitudinal prospective study

Objectives

High frequency of antimicrobial prescription and the nature of prolonged illness in COVID-19 increases risk for complicated bacteriuria and antibiotic resistance. We investigated risk factors for bacteriuria in the ICU and the correlation between antibiotic treatment and persistent bacteria.

Methods

We conducted a prospective longitudinal study with urine from indwelling catheters of 101 ICU patients from Uppsala University Hospital, Sweden. Samples were screened and isolates confirmed with MALDI-TOF and whole genome sequencing. Isolates were analyzed for AMR using broth microdilution. Clinical data were assessed for correlation with bacteriuria.

Results

Length of stay linearly correlated with bacteriuria (R² = 0.99, p ≤ 0.0001). 90% of patients received antibiotics, primarily the beta-lactams (76%) cefotaxime, piperacillin-tazobactam, and meropenem. We found high prevalence of Enterococcus (42%) being associated with increased cefotaxime prescription. Antibiotic-susceptible E. coli were found to cause bacteriuria despite concurrent antibiotic treatment when found in co-culture with Enterococcus.

Conclusion

Longer stays in ICUs increase the risk for bacteriuria in a predictable manner. Likely, high use of cefotaxime drives Enterococcus prevalence, which in turn permit co-colonizing Gram-negative bacteria. Our results suggest biofilms in urinary catheters as a reservoir of pathogenic bacteria with the potential to develop and disseminate AMR.

Antimicrobial Activity of Spices Popularly Used in Mexico against Urinary Tract Infections

Urinary tract infections (UTIs) are the most common infectious diseases worldwide. These infections are common in all people; however, they are more prevalent in women than in men. The main microorganism that causes 80-90% of UTIs is Escherichia coli. However, other bacteria such as Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Proteus mirabilis, and Klebsiella pneumoniae cause UTIs, and antibiotics are required to treat them. However, UTI treatment can be complicated by antibiotic resistance and biofilm formation. Therefore, medicinal plants, such as spices generally added to foods, can be a therapeutic alternative due to the variety of phytochemicals such as polyphenols, saponins, alkaloids, and terpenes present in their extracts that exert antimicrobial activity. Essential oils extracted from spices have been used to demonstrate their antimicrobial efficacy against strains of pathogens isolated from UTI patients and their synergistic effect with antibiotics. This article summarizes relevant findings on the antimicrobial activity of cinnamon, clove, cumin, oregano, pepper, and rosemary, spices popularly used in Mexico against the uropathogens responsible for UTIs.

Oral ciprofloxacin activity against ceftriaxone-resistant Escherichia coli in an in vitro bladder infection model

OBJECTIVES

Pharmacodynamic profiling of oral ciprofloxacin dosing for urinary tract infections caused by ceftriaxone-resistant Escherichia coli isolates with ciprofloxacin MIC ≥ 0.25 mg/L.

BACKGROUND

Urine-specific breakpoints for ciprofloxacin do not exist. However, high urinary concentrations may promote efficacy in isolates with low-level resistance.

METHODS

Ceftriaxone-resistant E. coli urinary isolates were screened for ciprofloxacin susceptibility. Fifteen representative strains were selected and tested using a dynamic bladder infection model. Oral ciprofloxacin dosing was simulated over 3 days (250 mg daily, 500 mg daily, 250 mg 12 hourly, 500 mg 12 hourly and 750 mg 12 hourly). The model was run for 96 h. Primary endpoint was change in bacterial density at 72 h. Secondary endpoints were follow-up change in bacterial density at 96 h and area-under-bacterial-kill-curve. Bacterial response was related to exposure (AUC0-24/MIC; Cmax/MIC). PTA was determined using Monte-Carlo simulation.

RESULTS

Ninety-three clinical isolates demonstrated a trimodal ciprofloxacin MIC distribution (modal MICs at 0.016, 0.25 and 32 mg/L). Fifteen selected clinical isolates (ciprofloxacin MIC 0.25-512 mg/L) had a broad range of quinolone-resistance genes. Following ciprofloxacin exposure, E. coli ATCC 25922 (MIC 0.008 mg/L) was killed in all dosing experiments. Six isolates (MIC ≥ 16 mg/L) regrew in all experiments. Remaining isolates (MIC 0.25-8 mg/L) regrew variably after an initial period of killing, depending on simulated ciprofloxacin dose. A >95% PTA, using AUC0-24/MIC targets, supported 250 mg 12 hourly for susceptible isolates (MIC ≤ 0.25 mg/L). For isolates with MIC ≤ 1 mg/L, 750 mg 12 hourly promoted 3 log10 kill at the end of treatment (72 h), 1 log10 kill at follow-up (96 h) and 90% maximal activity (AUBKC0-96).

CONCLUSIONS

Bladder infection modelling supports oral ciprofloxacin activity against E. coli with low-level resistance (ciprofloxacin MIC ≤ 1 mg/L) when using high dose therapy (750 mg 12 hourly).

Role of metabolism in uropathogenic Escherichia coli

Uropathogenic Escherichia coli (UPEC) is responsible for more than 75% of urinary tract infections (UTIs) and has been studied extensively to better understand the molecular underpinnings of infection and pathogenesis. Although the macromolecular adaptations UPEC employs - including the expression of virulence factors, adhesion molecules, and iron-acquisition systems - are well described, the role that metabolism plays in enabling infection is still unclear. However, a growing body of literature shows that metabolic function can have a profound impact on which strains can colonize the urinary tract. The goal of this review is to critically appraise this emerging body of literature to better understand the role that nutritional selection plays in enabling urinary tract colonization and the progression of UTIs.

M, Fatima A, Mahdi YK, Abdullah NH. Evaluation of Catechin Synergistic and Antibacterial Efficacy on Biofilm Formation and acrA Gene Expression of Uropathogenic E. coli Clinical Isolates

Uropathogenic Escherichia coli has a propensity to build biofilms to resist host defense and antimicrobials. Recurrent urinary tract infection (UTI) caused by multidrug-resistant, biofilm-forming E. coli is a significant public health problem. Consequently, searching for alternative medications has become essential. This study was undertaken to investigate the antibacterial, synergistic, and antibiofilm activities of catechin isolated from Canarium patentinervium Miq. against three E. coli ATCC reference strains (ATCC 25922, ATCC 8739, and ATCC 43895) and fifteen clinical isolates collected from UTI patients in Baghdad, Iraq. In addition, the expression of the biofilm-related gene, acrA, was evaluated with and without catechin treatment. Molecular docking was performed to evaluate the binding mode between catechin and the target protein using Autodock Vina 1.2.0 software. Catechin demonstrated significant bactericidal activity with a minimum inhibitory concentration (MIC) range of 1-2 mg/mL and a minimum bactericidal concentration (MBC) range of 2-4 mg/mL and strong synergy when combined with tetracycline at the MBC value. In addition, catechin substantially reduced E. coli biofilm by downregulating the acrA gene with a reduction percent ≥ 60%. In silico analysis revealed that catechin bound with high affinity (∆G = -8.2 kcal/mol) to AcrB protein (PDB-ID: 5ENT), one of the key AcrAB-TolC efflux pump proteins suggesting that catechin might inhibit the acrA gene indirectly by docking at the active site of AcrB protein.

Application of pharmacokinetic/pharmacodynamic concepts to the development of treatment regimens for sporadic canine urinary tract infections: Challenges and paths forward

Antimicrobial efficacy can be predicted based on infection site exposure to the antimicrobial agent relative to the in vitro susceptibility of the pathogen to that agent. When infections occur in soft tissues (e.g., muscle, blood, and ligaments), exposure at the infection site is generally assumed to reflect an equilibrium between the unbound concentrations in plasma and that in the interstitial fluids. In contrast, for sporadic urinary tract infections (UTIs) in dogs and uncomplicated UTIs in humans, the primary site of infection is the bladder wall. Infection develops when bacteria invade the host bladder urothelium (specifically, the umbrella cells that form the urine-contacting layer of the stratified uroepithelium) within which these bacteria can avoid exposure to host defenses and antimicrobial agents. Traditionally, pathogen susceptibility has been estimated using standardized in vitro tests that measure the minimal concentration that will inhibit pathogen growth (MIC). When using exposure-response relationships during drug development to explore dose optimization, these relationships can either be based upon an assessment of a correlation between clinical outcome, drug exposure at the infection site, and pathogen MIC, or upon benchmark exposure-response relationships (i.e., pharmacokinetic/pharmacodynamic indices) typically used for the various drug classes. When using the latter approach, it is essential that the unbound concentrations at the infection site be considered relative to the MIC within the biological matrix to which the pathogen will be exposed. For soft tissue infections, this typically is the unbound plasma concentrations versus MICs determined in standardized media such as cation-adjusted Mueller Hinton broth, which is how many indices were originally established. However, for UTIs, it is the unbound drug concentrations within the urine versus the MICs in the actual urine biophase that needs to be considered. The importance of these relationships and how they are influenced by drug resistance, resilience, and inoculum are discussed in this review using fluoroquinolones and beta-lactams as examples.

Urinary Tract Infections Caused by Uropathogenic Escherichia coli Strains—New Strategies for an Old Pathogen

Urinary tract infections (UTIs) are among the most common infections worldwide. Uropathogenic Escherichia coli (UPECs) are the main causative agent of UTIs. UPECs initially colonize the human host adhering to the bladder epithelium. Adhesion is followed by the bacterial invasion of urothelial epithelial cells where they can replicate to form compact aggregates of intracellular bacteria with biofilm-like properties. UPEC strains may persist within epithelial urothelial cells, thus acting as quiescent intracellular bacterial reservoirs (QIRs). It has been proposed that host cell invasion may facilitate both the establishment and persistence of UPECs within the human urinary tract. UPEC strains express a variety of virulence factors including fimbrial and afimbrial adhesins, invasins, iron-acquisition systems, and toxins, which cooperate to the establishment of long lasting infections. An increasing resistance rate relative to the antibiotics recommended by current guidelines for the treatment of UTIs and an increasing number of multidrug resistant UPEC isolates were observed. In order to ameliorate the cure rate and improve the outcomes of patients, appropriate therapy founded on new strategies, as alternative to antibiotics, needs to be explored. Here, we take a snapshot of the current knowledge of coordinated efforts to develop innovative anti-infective strategies to control the diffusion of UPECs.

Investigation of the effects of antimicrobial and anti-biofilm peptide IDR1018 and chitosan nanoparticles on ciprofloxacin-resistant Escherichia coli

Peptide IDR1018 and chitosan nanoparticles (CNs) showed antimicrobial and anti-biofilm activity against bacteria. In this study, the antimicrobial effects of peptide IDR1018 and CNs were evaluated on 50 clinical isolates of uropathogenic Escherichia coli (UPEC) resistant to ciprofloxacin. Ion gelation method was applied for CNs synthesis. Scanning electron microscope (SEM) and dynamic light scattering (DLS) were utilized to evaluate the nanoparticles. Antimicrobial and synergistic activity of peptide IDR1018 and CNs with ciprofloxacin were evaluated by microtiter broth dilution method. The checkerboard test was used to investigate the antimicrobial effects of IDR1018 and CNS in combination with ciprofloxacin. Anti-biofilm effect of ciprofloxacin, peptide IDR1018, and CNs was evaluated using crystal violet method. Fourteen (28%), 21 (42%), and 15 (30%) of clinical isolates produced strong, moderate, and weak biofilm, respectively. The CNs were spherical and uniform under electron microscopy with an average diameter of 246 nm. The minimum inhibitory concentration (MIC) values were 16-128, 20-40, and 375-750 (µg/ml) for ciprofloxacin, peptide IDR1018, and CNs, respectively. Fractional inhibitory concentration (FIC) analysis indicated a synergistic effect of ciprofloxacin in combination with peptide IDR1018, but in combination with CNs, this antibiotic showed an additive effect. Our results revealed that peptide IDR1018 and CNs have antimicrobial properties on UPEC isolates. Biofilm inhibition and biofilm eradication of clinical isolate were shown by peptide IDR1018 and CNs in a concentration-dependent manner. The antimicrobial agents alone and in combination decreased the number of viable bacteria in the biofilms. Therefore, these components seem to be a treating approach against biofilm-forming UPEC isolates.

Isolation and Characterization of Lytic Proteus Virus 309

Proteus mirabilis is frequently associated with complicated urinary tract infections (UTIs) and is the main cause of catheter-associated urinary tract infections (CAUTIs). Treatment of such infections is complicated and challenging due to the biofilm forming abilities of P. mirabilis. If neglected or mistreated, infections may lead to life-threating conditions such as cystitis, pyelonephritis, kidney failure, and bacteremia that may progress to urosepsis. Treatment with antibiotics, especially in cases of recurring and persistent infections, leads to the development of resistant strains. Recent insights into phage therapy and using phages to coat catheters have been evaluated with many studies showing promising results. Here, we describe a highly lytic bacteriophage, Proteus_virus_309 (41,740 bp), isolated from a wastewater treatment facility in Cape Town, South Africa. According to guidelines of the International Committee on Taxonomy of Viruses (ICTV), bacteriophage 309 is a species within the genus Novosibovirus. Similar to most members of the genus, bacteriophage 309 is strain-specific and lyse P. mirabilis in less than 20 min.

Plasmid-mediated quinolone resistance determinants in fluoroquinolone-nonsusceptible Escherichia coli isolated from patients with urinary tract infections in a university hospital, 2009-2010 and 2020: PMQR in UTI E. coli

OBJECTIVES

This study aimed to characterize the plasmid-mediated quinolone resistance (PMQR) in fluoroquinolone non-susceptible E. coli (FQNSEC) isolated from patients with urinary tract infections (UTIs) in 2019-2010 and 2020.

METHODS

A total of 844 E. coli isolates were collected from UTI patients at National Cheng Kung University Hospital (NCKUH). The antimicrobial susceptibility of E. coli isolates to 21 antibiotics was determined by disk diffusion tests. The distribution of phylogenetic groups, virulence factor, and PMQR genes, was determined by PCR. Conjugation assays were performed to investigate the transferrability of qnr genes from FQNSEC isolates to E. coli C600.

RESULTS

We found 211 (41.9%) and 152 (44.7%) E. coli isolates were FQNSEC in 2009-2010 and 2020, respectively. Phylogenetic group B2 was dominant in FQNSEC isolates (52.34%), followed by group F (10.47%), group B1 (9.64%), and group D (9.64%). FQNSEC isolates were more resistant to 17 of 19 tested antimicrobial agents, compared to the FQ susceptible E. coli. PMQR screening results showed that 34, 22, and 10 FQNSEC isolates containing aac(6')-Ib-cr, qnr genes, and efflux pump genes (qepA or oqxAB), respectively. PMQR E. coli isolates were more non-susceptible to gentamicin, amoxicillin, ampicillin/sulbactam, imipenem, cefazolin, cefuroxime, cefmetazole, ceftriaxone, ceftazidime, and cefepime, compared to non-PMQR FQNSEC. Moreover, 16 of 22 qnr-carrying plasmids were transferrable to the recipient C600.

CONCLUSION

Here, we reported the high prevalence of MDR- and XDR-E. coli in FQNSEC isolates. Moreover, qnr-carrying plasmids were highly transferable and lead to the resistance to other classes of antibiotics in the transconjugants.

The urothelium: a multi-faceted barrier against a harsh environment

All mucosal surfaces must deal with the challenge of exposure to the outside world. The urothelium is a highly specialized layer of stratified epithelial cells lining the inner surface of the urinary bladder, a gruelling environment involving significant stretch forces, osmotic and hydrostatic pressures, toxic substances, and microbial invasion. The urinary bladder plays an important barrier role and allows the accommodation and expulsion of large volumes of urine without permitting urine components to diffuse across. The urothelium is made up of three cell types, basal, intermediate, and umbrella cells, whose specialized functions aid in the bladder's mission. In this review, we summarize the recent insights into urothelial structure, function, development, regeneration, and in particular the role of umbrella cells in barrier formation and maintenance. We briefly review diseases which involve the bladder and discuss current human urothelial in vitro models as a complement to traditional animal studies.

Repeated Exposure of Escherichia coli to High Ciprofloxacin Concentrations Selects gyrB Mutants That Show Fluoroquinolone-Specific Hyperpersistence

Recent studies have shown that not only resistance, but also tolerance/persistence levels can evolve rapidly in bacteria exposed to repeated antibiotic treatments. We used in vitro evolution to assess whether tolerant/hyperpersistent Escherichia coli ATCC25922 mutants could be selected under repeated exposure to a high ciprofloxacin concentration. Among two out of three independent evolution lines, we observed the emergence of gyrB mutants showing an hyperpersistence phenotype specific to fluoroquinolones, but no significant MIC increase. The identified mutation gives rise to a L422P substitution in GyrB, that is, outside of the canonical GyrB QRDR. Our results indicate that mutations in overlooked regions of quinolone target genes may impair the efficacy of treatments via an increase of persistence rather than resistance level, and support the idea that, in addition to resistance, phenotypes of tolerance/persistence of infectious bacterial strains should receive considerations in the choice of antibiotic therapies.

Environmental, Microbiological, and Immunological Features of Bacterial Biofilms Associated with Implanted Medical Devices

The spread of biofilms on medical implants represents one of the principal triggers of persistent and chronic infections in clinical settings, and it has been the subject of many studies in the past few years, with most of them focused on prosthetic joint infections. We review here recent works on biofilm formation and microbial colonization on a large variety of indwelling devices, ranging from heart valves and pacemakers to urological and breast implants and from biliary stents and endoscopic tubes to contact lenses and neurosurgical implants. We focus on bacterial abundance and distribution across different devices and body sites and on the role of environmental features, such as the presence of fluid flow and properties of the implant surface, as well as on the interplay between bacterial colonization and the response of the human immune system.

Novel Insights on Plant Extracts to Prevent and Treat Recurrent Urinary Tract Infections

Urinary tract infections (UTI) represent one of the most widespread infections, and frequent recurrent episodes, induced mostly by uropathogenic Escherichia coli, make them increasingly difficult to treat. Long-term antibiotic therapy is an effective approach to treat recurrent UTI but generates adverse effects, including the emergence of pathogenic strains resistant to the vast majority of antibiotics. These drawbacks have enhanced the interest toward new alternatives based on plant extracts to prevent and treat recurrent UTI, especially in a synergistic antibiotic approach. Therefore, this review highlights the potential of some medicinal plants to be used in the management of recurrent UTI, including plants that have been approved for the treatment of urinary infections and promising, but less studied, plant candidates with proven anti-uropathogenic activity. Pomegranate (Punica granatum L.), black chokeberry (Aronia melanocarpa Michx.), and cornelian cherry (Cornus mas L.) have great potential to be used for prevention or in a combined antibiotic therapy to cure UTI, but more studies and clinical trials in specific population groups are required. Further progress in developing plant-based products to cure rUTI will be supported by advances in UTI pathogenesis and human-based models for a better understanding of their pharmacological activities.

OUP accepted manuscript

Objectives

STM-001, a retargeted glycopeptide, is active against MDR E. coli expressing ESBLs including carbapenemases. Herein, we assessed its capability to combat E. coli complicated urinary tract infections (cUTI) in mice driven by clinically important serine (CTX-M-15) and metallo-β-lactamases (NDM-1).

Methods

Plasma and urine pharmacokinetics following IV administration of STM-001 (1–50 mg/kg) were determined in mice via LC-MS/MS. The effects on bacterial burden (kidney, bladder and urine) were determined in a 7 day mouse cUTI model whereby STM-001 was administered q12h or q24h at 2–100 mg/kg/day from Day 4. Efficacy was assessed by the change in log₁₀ cfu/g or log₁₀ cfu/mL from vehicle-treated infected mice.

Results

MICs of STM-001 for CTX-M-15 and NDM-1 E. coli were 8 and 16 mg/L, respectively. Blood pharmacokinetic profile was linear and dose-dependent with low clearance of 9.49 ± 0.31 mL/min/kg, V = 0.63 ± 0.02 L/kg and t_½ = 1.16 ± 0.03 h. High STM-001 concentrations were recovered in urine 0–8 h post-administration, reaching up to 120-fold above its MIC. In cUTI efficacy studies, STM-001 (1–50 mg/kg, q12h) reduced CTX-M-15 burden by log₁₀ 4.31 (kidney), 3.95 (bladder) and 4.82 (urine) compared with vehicle-treated animals (P < 0.0001). STM-001 also reduced NDM-1 burden by log₁₀ 3.89 (kidney), 3.76 (bladder) and 3.08 (urine) (P < 0.0001), with similar inhibitory effects following q24h dosing.

Conclusions

STM-001 was highly effective in reducing E. coli burden in kidney, bladder and urine in mouse cUTI models. The observed efficacy with either dosing regimen indicates potential low humanized doses of 1–5 mg/kg. These data support further development of STM-001 as an innovative, carbapenem-sparing antibiotic to combat human cUTIs.

Urine collection devices to reduce contamination in urine samples for diagnosis of uncomplicated UTI: a single-blind randomised controlled trial in primary care

BACKGROUND

Urine collection devices (UCDs) are being marketed and used in clinical settings to reduce urine sample contamination, despite inadequate supporting evidence.

AIM

To determine whether UCDs, compared with standardised instructions for urine sample collection, reduce the proportion of contaminated samples.

DESIGN AND SETTING

Single-blind randomised controlled trial in general practices in England and Wales.

METHOD

Women aged ≥18 years presenting with symptoms attributable to urinary tract infection (UTI) were randomised (1:1:1) to use either a Peezy UCD or a Whiz Midstream UCD, or were given standardised verbal instructions (SVI) for midstream sample collection. The primary outcome was the proportion of urine samples reported as contaminated by microbiology laboratory analysis.

RESULTS

A total of 1264 women (Peezy UCD: n = 424; Whiz Midstream UCD: n = 421; SVI: n = 419) were randomised between October 2016 and August 2018. Ninety women were excluded from the primary analysis as a result of ineligibility or lack of primary outcome data, leaving 1174 (Peezy UCD: n = 381; Whiz Midstream UCD: n = 390; SVI: n = 403) for intention-to-treat analysis. The proportion of contaminated samples was 26.5% with the Peezy UCD, 28.2% with the Whiz Midstream UCD, and 29.0% with SVI (relative risk: Peezy UCD versus SVI = 0.91, 95% CI = 0.76 to 1.09, P = 0.32; Whiz Midstream UCD versus SVI = 0.98, 95% CI = 0.97 to 1.20, P = 0.82). There were 100 (25.3%) device failures with the Peezy UCD and 35 (8.8%) with the Whiz Midstream UCD; the proportion of contaminated samples was similar after device failure samples were excluded.

CONCLUSION

Neither the Peezy UCD nor the Whiz Midstream UCD reduced urine sample contamination when used by women presenting to primary care with suspected UTI. Their use cannot be recommended for this purpose in this setting.