A Porcine Model for Urinary Tract Infection

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.

The infectious capacity of Enterococcus faecalis, Staphylococcus aureus, and Staphylococcus saprophyticus in a porcine model of urinary tract infection

The purpose of this study was to establish a porcine model of urinary tract infection (UTI) with gram-positive uropathogens. Ten female domestic pigs were experimentally inoculated with human UTI isolates of Enterococcus faecalis (n = 3), Staphylococcus saprophyticus (n = 3), or Staphylococcus aureus (n = 4) and followed with regular urine samples. Bladders and kidneys were aseptically removed at termination (5-7 days post infection) and assessed by gross pathology and bacterial enumeration. Enterococcus faecalis (n = 3 of 3) and S. aureus (n = 2 of 4) successfully colonized the pig bladders. Inoculation with S. saprophyticus never resulted in detectable bacteriuria. All infected pigs had cleared the infection spontaneously before termination. Surprisingly, three (of four) pigs inoculated with S. aureus led to spontaneous infection with opportunistic pathogens. Also, one pig colonized with E. faecalis resulted in spontaneous infection with E. coli. In conlusion, the pig supports experimental UTI with E. faecalis for up to 24 h but not prolonged infection. S. aureus and S. saprophyticus fails to cause UTI in pigs and other animals should be considered for studying these pathogens.

Urinary bladder catheterisation of female pigs: Influence of bladder content and Escherichia coli urinary tract infection on procedural outcome

Catheterisation of the urinary bladder is needed in many types of human disease models in pigs. Based on our extensive experience with the pig as an infection model, we here demonstrate an approach of catheterising domestic pigs (40 attempts) and Göttingen minipigs (10 attempts) using a blinded method, that is, without speculums or videoscopes to visualise the urethral opening. The procedure was tested on control animals and pigs with experimental Escherichia coli urinary tract infection (UTI) to assess the potential influence of this condition on procedural outcome. Lastly, we performed cystoscopy in three animals to visualise the route to the urethra and to localise potential anatomical obstacles. All domestic pigs were catheterised successfully in an average of 2 minutes and 23 seconds, and this was not influenced by UTI (p  =  0.06) or bladder urine content at the time of catheterisation (p = 0.32). All Göttingen minipigs were successfully catheterised in an average of 4 minutes and 27 seconds. We conclude that blinded catheterisation is a fast and reliable approach that can be performed in pigs with or without UTI with minimal risk of trauma or contamination.

Evaluation of urine dipstick tests in experimental porcine urinary tract infection with uropathogenic Escherichia coli

Urinary tract infection is a common disease in pigs and a major reason for sows to be culled. The disease, however, is difficult to diagnose due to lack of distinct clinical signs in the animals. We evaluated the diagnostic value of two commercial urine dipstick tests in 10 pigs using an experimental model of Escherichia coli urinary tract infection. Urine collected at baseline and 48 h after inoculation were analyzed. We show that dipstick tests positive of blood, leucocytes and particularly nitrite are very specific for E. coli UTI with a 100% positive predictive value.

Porcine spinal cord injury model for translational research across multiple functional systems

Animal models are necessary to identify pathological changes and help assess therapeutic outcomes following spinal cord injury (SCI). Small animal models offer value in research in terms of their easily managed size, minimal maintenance requirements, lower cost, well-characterized genomes, and ability to power research studies. However, despite these benefits, small animal models have neurologic and anatomical differences that may influence translation of results to humans and thus limiting the success of their use in preclinical studies as a direct pipeline to clinical studies. Large animal models, offer an attractive intermediary translation model that may be more successful in translating to the clinic for SCI research. This is largely due to their greater neurologic and anatomical similarities to humans. The physical characteristics of pig spinal cord, gut microbiome, metabolism, proportions of white to grey matter, bowel anatomy and function, and urinary system are strikingly similar and provide great insight into human SCI conditions. In this review, we address the variety of existing porcine injury models and their translational relevance, benefits, and drawbacks in modeling human systems and functions for neurophysiology, cardiovascular, gastrointestinal and urodynamic functions.

Microbiota-Pain Association; Recent Discoveries and Research Progress

The relationship between gut microbiota and pain, such as visceral pain, headaches (migraine), itching, prosthetic joint infection (PJI), chronic abdominal pain (CAP), joint pain, etc., has received increasing attention. Several parts of the evidence suggest that microbiota is one of the most important pain modulators and they can regulate pain in the central and peripheral nervous systems. Any alteration in microbiota by diet or antibiotics mediation may characterize a novel therapeutic strategy for pain management. The present study includes the most up-to-date and influential scientific findings on the association of microbiota with pain, despite the fact that the underlying mechanism is not identified in most cases. According to recent research, identifying the molecular mechanisms of the microbiota-pain pathway can have a unique perspective in treating many diseases, even though there is a long way to reach the ideal point. This study will stress the influence of microbiota on the common diseases that can stimulate the pain with a focus on underlying mechanisms.

Clean-catching urine from pigs: A method for collecting quality specimens for urinalysis and microbiological culturing in a laboratory environment

Urine is an important biological specimen for assessing various metabolic functions and drug clearance. In urinary tract infection research, urine is particularly important as urinary bacterial titres constitute the main diagnostic outcome for assessing the course of infection. Collecting uncontaminated urine samples from pigs can be done by bladder catheterization or suprapubic bladder aspiration, which are both laborious and invasive procedures that require the need for anaesthesia. To improve animal welfare and optimize urine sampling protocols, we developed a method of clean-catching midstream urine specimens from pigs during spontaneous micturition. The quality of urine specimens collected by clean-catch, bladder catheter and suprapubic bladder aspiration were compared using microbiological culturing. We show that urine specimens collected by clean-catch are only minimally contaminated by skin- and vaginal-commensals with no influence on urinary bacterial titres during ongoing infection. In conclusion, we describe a method in which spontaneous micturition can be prompted in pigs, facilitating fast and reliable collection of quality specimens suitable for microbiological culturing. The method supersedes the need for anaesthesia, which not only represents a considerable refinement in terms of animal welfare but also facilitates more frequent collection of specimens that can enhance the scientific outcome of experimental animal studies in pigs.

Development of an ex-vivo porcine lower urinary tract model to evaluate the performance of urinary catheters

Intermittent catheterization is the gold standard method for bladder management in individuals with urinary retention and/or incontinence. It is therefore important to understand the performance of urinary catheters, especially on parameters associated to risks of developing urinary tract infections, and that may impact the quality of life for urinary catheter users. Examples of such parameters include, urine flowrate, occurrence of flow-stops, and residual urine left in the bladder after flow-stop. Reliable in-vitro and/or ex-vivo laboratory models represent a strong asset to assess the performance of urinary catheters, preceding and guiding in-vivo animal studies and/or human clinical studies. Existing laboratory models are generally simplified, covering only portions of the catheterization process, or poorly reflect clinical procedures. In this work, we developed an ex-vivo porcine lower urinary tract model that better reflects the catheterization procedure in humans and allows to investigate the performance of standard of care catheters. The performance of three standard of care catheters was investigated in the developed model showing significant differences in terms of flowrate. No differences were detected in terms of residual volume in the bladder at first flow-stop also when tuning the abdominal pressure to mimic a sitting down and standing up position. A newly discovered phenomenon named hammering was detected and measured. Lastly, mucosal suction was observed and measured in all standard of care catheters, raising the concern for microtrauma during catheterization and a need for new and improved urinary catheter designs. Results obtained with the ex-vivo model were compared to in-vivo studies, highlighting similar concerns.

Genome-wide analysis of fitness factors in uropathogenic Escherichia coli in a pig urinary tract infection model

Uropathogenic Escherichia coli (UPEC) is the primary cause of urinary tract infections (UTIs) in animals and humans. We applied Transposon-Directed Insertion Site sequencing (TraDIS) to determine the fitness genes in two well-characterized UPEC strains, UTI89 and CFT073, in order to identify fitness factors during UTI in a pig model. This novel animal model better reflects the course of UTI in humans than the commonly used mouse model, and facilitates the differentiation between sessile and planktonic UPEC populations. A total of 854 and 483 genes in UTI89 and CFT073, respectively, were predicted to contribute to growth in pig urine, and 1257 and 764, were scored as required for colonization of the bladder. The combined list of fitness genes for growth in urine and cystitis contained 741 (UTI89) and 439 (CFT073) genes. The essential genes for growth on LB agar media supplemented with kanamycin and the fitness factors during growth in human urine were also analyzed in CFT073. A total of 457 essential genes were identified and the pool of fitness genes for growth in human urine included 215 genes. The gene rfaG, which is involved in lipopolysaccharide biosynthesis, was included in all the fitness-gene-lists and was further confirmed to be relevant for all the conditions tested regardless of the host and the strain. Thus, this gene may represent a promising target for the development of new therapeutic strategies against UTI UPEC-associated. Besides this important observation, the study revealed strain-specific differences in gene-essentiality as well as in the fitness-gene-repertoire for growth in human urine and UTI of the pig model, and it identified novel factors required for UPEC-induced UTIs.

A new catheter-integrated drug-delivery system for controlled intravesical mitomycin C release

BACKGROUND

Intravesical treatment of bladder cancer is preferred over systemic administration. However, the efficacy of intravesical instillations is challenged by the periodic voiding that flushes out the instilled drug and ultimately reduces drug exposure to the bladder epithelium. Here, we demonstrate a new catheter-integrated drug-delivery concept that utilizes a silicone-based interpenetrating polymer network (IPN) as material for the catheter balloon, to facilitate continuous release of the bladder cancer adjuvant, Mitomycin C, from a balloon-reservoir to the urinary bladder.

METHODS

Long-term release properties and anti-carcinoma cell efficacy of released drug was investigated in vitro. Short-term release experiments were performed in live pigs to evaluate the IPN prototype catheter in a physiological relevant environment in vivo.

RESULTS

Sustained zero-order release of Mitomycin C was achieved for 12 days in vitro without refilling the balloon. Mitomycin C was released from the IPN-balloons into the urinary bladder of live pigs in concentrations adequate to inhibit carcinoma cell growth.

CONCLUSION

The IPN catheter represents a new drug-delivery concept for prolonged Mitomycin C delivery to the urinary bladder.

Uropathogenic Escherichia coli can cause cystitis at extremely low inocula in a pig model

Urinary tract infection (UTI) is one of the most common bacterial infections worldwide. Experimental models that accurately reflect the high susceptibility to UTI in humans have, however, been lacking. This situation has limited detailed research into the early bladder colonization by uropathogens and the early innate defence mechanisms elicited to prevent this. We recently presented a model of urinary tract infection in pigs, animals that are naturally susceptible to UTI and have greater similarity to the physiology and anatomy of the human urinary tract than traditional rodent UTI models. In the current study, we used the pig model to investigate the minimal infectious inoculum of uropathogenic Escherichia coli, the most common cause of urinary tract infection. We show that in this animal a few individual bacteria that come into contact with the urothelium can give rise to fulminant cystitis, indicating the high infectious potential of uropathogenic E. coli.

Housing Conditions and a Challenge with Lipopolysaccharide on the Day of Estrus Can Influence Gene Expression of the Corpus Luteum in Gilts

The corpus luteum (CL) is a temporary endocrine gland that plays a decisive role in the reproductive physiology of gilts. Recently, it has been suggested that exogenous factors may compromise the normal functioning of the CL. In the present study, we aimed to understand to what extent an acute and systemic challenge with lipopolysaccharide (LPS) on the day of estrus could compromise gene expression of gilts’ CLs housed in different welfare conditions. For this, we housed 42 gilts in three different housing systems: crates, indoor group pens, and outdoor housing. Then, we challenged six females from each group with LPS and eight with saline (SAL) on the day of estrus. After slaughtering the gilts on the fifth day after the challenge, ovaries were collected for gene expression analysis by RT-qPCR. Housing system and LPS challenge did not have a significant interaction for any genes evaluated; thus, their effects were studied separately. We identified significant (p < 0.05) downregulation of the angiogenic genes VEGF and FTL1 among LPS-challenged animals. Meanwhile, we also observed upregulation of HSD3B1 gene among LPS-challenged animals. We found that STAR and LHCGR genes were differentially expressed depending on the housing system, which indicates that the environment may affect adaptation capabilities. Our results indicate that an acute health challenge on the estrus day alters CL gene expression; however, the role of the housing system remains uncertain.

A Biomimetic Porcine Urothelial Model for Assessing Escherichia coli Pathogenicity

Urinary tract infections can be severe, sometimes fatal, diseases whose etiological pathogens are predominantly uropathogenic strains of E. coli (UPEC). To investigate the UPEC pathogenesis, several models have already been established with minor or major disadvantages. The aim was to develop a simple, fast, and inexpensive biomimetic in vitro model based on normal porcine urothelial (NPU) cells that are genetically and physiologically similar to human bladder urothelium and to perform basic studies of E. coli pathogenicity. Initially, the model was tested using a set of control E. coli strains and, subsequently, with human E. coli strains isolated either from patients with urinary infections or from the feces of healthy individuals. A drop in viability of NPU cells was used as a measure of the pathogenicity of the individual strain tested. To visualize the subcellular events, transmission and scanning electron microscopy was performed. The strains were tested for the presence of different virulence-associated genes, phylogroup, type of core lipid, O-serotype, and type of lipopolysaccharide and a statistical analysis of possible correlations between strains’ characteristics and the effect on the model was performed. Results showed that our model has the discriminatory power to distinguish pathogenic from non-pathogenic E. coli strains, and to identify new, potentially pathogenic strains.

Translating pharmacology models effectively to predict therapeutic benefit

Many in vitro and in vivo models are used in pharmacological research to evaluate the role of targeted proteins in a disease. Understanding the translational relevance and limitation of these models for analyzing the disposition, pharmacokinetic/pharmacodynamic (PK/PD) profile, mechanism, and efficacy of a drug, is essential when selecting the most appropriate model of the disease of interest and predicting clinically efficacious doses of the investigational drug. Here, we review selected animal models used in ophthalmology, infectious diseases, oncology, autoimmune diseases, and neuroscience. Each area has specific challenges around translatability and determination of an efficacious dose: new patient-specific dosing methods could help overcome these limitations.

Gut Microbiota of Pigs Metabolizes Extracts of Filipendula ulmaria and Orthosiphon aristatus-Herbal Remedies Used in Urinary Tract Disorders

Urinary tract infections influence the mortality rate in pigs and are linked to extensive antibiotic usage in the farm industry. Filipendula ulmaria (L.) Maxim. and Orthosiphon aristatus (Blume) Miq. are widespread medicinal plants traditionally used to treat urinary tract disorders. As their preparations are orally administered, the metabolism of their constituents by gut microbiota before absorption should be considered. Until now, no experiments had been performed to describe the biotransformation of tthose plants' extracts by animal gut microbiota. The study evaluates the influence of pig intestinal microbiota on the structure of active compounds in flowers of F. ulmaria and leaves of O. aristatus. The incubations of the extracts with piglet gut microbiota were performed in anaerobic conditions, and the samples of the batch culture were collected for 24 h. In F. ulmaria, the main metabolites were quercetin and kaempferol, which were products of the deglycosylation of flavonoids. After 24 h incubation of O. aristatus extract with the piglet gut microbiota, 2 main metabolites were observed. One, tentatively identified as 3-(3-dihydroxyphenyl)propionic acid, is likely the primary metabolite of the most abundant depsides and phenolic acids. The results confirm the formation of the compounds with anti-inflammatory and diuretic activity in the microbiota cultures, which might suggest F. ulmaria and O. aristatus for treating urinary tract disorders in piglets. Based on the similarities of human and pig gut microbiota, the pig model can help estimate the metabolic pathways of natural products in humans.

A Pilot Single Cell Analysis of the Zebrafish Embryo Cellular Responses to Uropathogenic Escherichia coli Infection

Background: Uropathogenic Escherichia coli (UPEC) infections are common and when they disseminate can be of high morbidity. Methods: We studied the effects of UPEC infection using single cell RNA sequencing (scRNAseq) in zebrafish. Bulk RNA sequencing has historically been used to evaluate gene expression patterns, but scRNAseq allows gene expression to be evaluated at the single cell level and is optimal for evaluating heterogeneity within cell types and rare cell types. Zebrafish cohorts were injected with either saline or UPEC,and scRNAseq and canonical pathway analyses were performed. Results: Canonical pathway analysis of scRNAseq data provided key information regarding innate immune pathways in the cells determined to be thymus cells, ionocytes, macrophages/monocytes, and pronephros cells. Pathways activated in thymus cells included interleukin 6 (IL-6) signaling and production of reactive oxygen species. Fc receptor-mediated phagocytosis was a leading canonical pathway in the pronephros and macrophages. Genes that were downregulated in UPEC vs saline exposed embryos involved the cellular response to the Gram-negative endotoxin lipopolysaccharide (LPS) and included Forkhead Box O1a (Foxo1a), Tribbles Pseudokinase 3 (Trib3), Arginase 2 (Arg2) and Polo Like Kinase 3 (Plk3). Conclusions: Because 4-day post fertilization zebrafish embryos only have innate immune systems, the scRNAseq provides insights into pathways and genes that cell types utilize in the bacterial response. Based on our analysis, we have identified genes and pathways that might serve as genetic targets for treatment and further investigation in UPEC infections at the single cell level.

Genome-wide analysis of fitness-factors in uropathogenic Escherichia coli during growth in laboratory media and during urinary tract infections

Uropathogenic Escherichia coli (UPEC) UTI89 is a well-characterized strain, which has mainly been used to study UPEC virulence during urinary tract infection (UTI). However, little is known on UTI89 key fitness-factors during growth in lab media and during UTI. Here, we used a transposon-insertion-sequencing approach (TraDIS) to reveal the UTI89 essential-genes for in vitro growth and fitness-gene-sets for growth in Luria broth (LB) and EZ-MOPS medium without glucose, as well as for human bacteriuria and mouse cystitis. A total of 293 essential genes for growth were identified and the set of fitness-genes was shown to differ depending on the growth media. A modified, previously validated UTI murine model, with administration of glucose prior to infection was applied. Selected fitness-genes for growth in urine and mouse-bladder colonization were validated using deletion-mutants. Novel fitness-genes, such as tusA, corA and rfaG; involved in sulphur-acquisition, magnesium-uptake, and LPS-biosynthesis, were proved to be important during UTI. Moreover, rfaG was confirmed as relevant in both niches, and therefore it may represent a target for novel UTI-treatment/prevention strategies.

Escherichia coli type-1 fimbriae are critical to overcome initial bottlenecks of infection upon low-dose inoculation in a porcine model of cystitis

Most uropathogenic Escherichia coli (UPEC) express type-1 fimbriae (T1F), a key virulence factor for urinary tract infection (UTI) in mice. Evidence that conclusively associates this pilus with uropathogenesis in humans has, however, been difficult to obtain. We used an experimental porcine model of cystitis to assess the role of T1F in larger mammals more closely related to humans. Thirty-one pigs were infected with UPEC strain UTI89 or its T1F deficient mutant, UTI89ΔfimH, at inoculum titres of 10² to 10⁸ colony forming units per millilitre. Urine and blood samples were collected and analysed 7 and 14 days post-inoculation, and whole bladders were removed at day 14 and analysed for uroepithelium-associated UPEC. All animals were consistently infected and reached high urine titres independent of inoculum titre. UTI89ΔfimH successfully colonized the bladders of 1/6 pigs compared to 6/6 for the wild-type strain. Intracellular UPEC were detectable in low numbers in whole bladder explants. In conclusion, low doses of UPEC are able to establish robust infections in pigs, similar to what is presumed in humans. T1F are critical for UPEC to surpass initial bottlenecks during infection but may be dispensable once infection is established. While supporting the conclusions from mice studies regarding a general importance of T1F in successfully infecting the host, the porcine UTI models’ natural high, more human-like, susceptibility to infection, allowed us to demonstrate a pivotal role of T1F in initial establishment of infection upon a realistic low-inoculum introduction of UPEC in the bladder.

A Novel Device-Integrated Drug Delivery System for Local Inhibition of Urinary Tract Infection

Background: Catheter-associated urinary tract infection (CAUTI) is a frequent community-acquired infection and the most common nosocomial infection. Here, we developed a novel antimicrobial catheter concept that utilizes a silicone-based interpenetrating polymer network (IPN) as balloon material to facilitate a topical slow-release prophylaxis of antibacterial agents across the balloon to the urinary bladder.

Methods: The balloon material was achieved by modifying low shore hardness silicone tubes with a hydrogel interpenetrating polymer in supercritical CO₂ using the sequential method. Release properties and antibacterial efficacy of the IPN balloon treatment concept was investigated in vitro and in a porcine CAUTI model developed for the study. In the latter, Bactiguard Infection Protection (BIP) Foley catheters were also assessed to enable benchmark with the traditional antimicrobial coating principle.

Results: Uropathogenic Escherichia coli was undetectable in urinary bladders and on retrieved catheters in the IPN treatment group as compared to control that revealed significant bacteriuria (>10⁵ colony forming units/ml) as well as catheter-associated biofilm. The BIP catheters failed to prevent E. coli colonization of the bladder but significantly reduced catheter biofilm formation compared to the control.

Conclusion: The IPN-catheter concept provides a novel, promising delivery route for local treatment in the urinary tract.

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

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

Perspective: Humanized Pig Models of Bladder Cancer

Bladder cancer (BC) is the 10th most common neoplasia worldwide and holds expensive treatment costs due to its high recurrence rates, resistance to therapy and the need for lifelong surveillance. Thus, it is necessary to improve the current therapy options and identify more effective treatments for BC. Biological models capable of recapitulating the characteristics of human BC pathology are essential in evaluating the effectiveness of new therapies. Currently, the most commonly used BC models are experimentally induced murine models and spontaneous canine models, which are either insufficient due to their small size and inability to translate results to clinical basis (murine models) or rarely spontaneously observed BC (canine models). Pigs represent a potentially useful animal for the development of personalized tumors due to their size, anatomy, physiology, metabolism, immunity, and genetics similar to humans and the ability to experimentally induce tumors. Pigs have emerged as suitable biomedical models for several human diseases. In this sense, the present perspective focuses on the genetic basis for BC; presents current BC animal models available along with their limitations; and proposes the pig as an adequate animal to develop humanized large animal models of BC. Genetic alterations commonly found in human BC can be explored to create genetically defined porcine models, including the BC driver mutations observed in the FGFR3, PIK3CA, PTEN, RB1, HRAS, and TP53 genes. The development of such robust models for BC has great value in the study of pathology and the screening of new therapeutic and diagnostic approaches to the disease.

Self-Limiting Mussel Inspired Thin Antifouling Coating with Broad-Spectrum Resistance to Biofilm Formation to Prevent Catheter-Associated Infection in Mouse and Porcine Models

Catheter-associated urinary tract infections (CAUTIs) are one of the most commonly occurring hospital-acquired infections. Current coating strategies to prevent catheter-associated biofilm formation are limited by their poor long-term efficiency and limited applicability to diverse materials. Here, the authors report a highly effective non-fouling coating with long-term biofilm prevention activity and is applicable to diverse catheters. The thin coating is lubricous, stable, highly uniform, and shows broad spectrum prevention of biofilm formation of nine different bacterial strains and prevents the migration of bacteria on catheter surface. The coating method is adapted to human-sized catheters (both intraluminal and extraluminal) and demonstrates long-term biofilm prevention activity over 30 days in challenging conditions. The coated catheters are tested in a mouse CAUTI model and demonstrate high efficiency in preventing bacterial colonization of both Gram-positive and Gram-negative bacteria. Furthermore, the coated human-sized Foley catheters are evaluated in a porcine CAUTI model and show consistent efficiency in reducing biofilm formation by Escherichia coli (E. coli) over 95%. The simplicity of the coating method, the ability to apply this coating on diverse materials, and the high efficiency in preventing bacterial adhesion increase the potential of this method for the development of next generation infection resistant medical devices.

Image-guided study of swine anatomy as a tool for urologic surgery research and training

PURPOSE

To describe the anatomy of the swine urinary system using computed tomography and to discuss the role of this animal as an experimental model for urological procedures.

METHODS

Three male Landrace pigs underwent computed tomography and the anatomy of the urinary system and renal circulation was analyzed and described.

RESULTS

In all animals, 2 kidneys, 2 ureters and one bladder were identified. Each kidney presented a single renal artery vascularization, with a mean diameter on the right of 4.45 and 5.31 mm on the left (p < 0.0001) and single renal vein drainage, with a mean diameter on the right of 5.78 and 5.82 mm on the left (p = 0.0336). The average renal length was 9.85 cm on the right and 10.30 cm on the left (p < 0.0001). The average renal volume was 113.70 cm3 on the right and 109.70 cm3 on the left (p < 0.0001). The average length of the ureter was 19.78 cm on the right and 22.08 cm on the left (p < 0.0001). The average bladder volume was 423.70 cm3.

CONCLUSIONS

The data obtained show similarities with human anatomy, suggesting the viability of the swine model for planning preclinical trials, basic research, refinement in experimental surgery and surgical training for urological procedures.

Antimicrobial pharmacokinetics and preclinical in vitro models to support optimized treatment approaches for uncomplicated lower urinary tract infections

INTRODUCTION

Urinary tract infections (UTIs) are extremely common. Millions of people, particularly healthy women, are affected worldwide every year. One-in-two women will have a recurrence within 12-months of an initial UTI. Inadequate treatment risks worsening infection leading to acute pyelonephritis, bacteremia and sepsis. In an era of increasing antimicrobial resistance, it is critical to provide optimized antimicrobial treatment.

AREAS COVERED

Literature was searched using PubMed and Google Scholar (up to 06/2020), examining the etiology, diagnosis and oral antimicrobial therapy for uncomplicated UTIs, with emphasis on urinary antimicrobial pharmacokinetics (PK) and the application of dynamic in vitro models for the pharmacodynamic (PD) profiling of pathogen response.

EXPERT OPINION

The majority of antimicrobial agents included in international guidelines were developed decades ago without well-described dose-response relationships. Microbiology laboratories still apply standard diagnostic methodology that has essentially remained unchanged for decades. Furthermore, it is uncertain how relevant standard in vitro susceptibility is for predicting antimicrobial efficacy in urine. In order to optimize UTI treatments, clinicians must exploit the urine-specific PK of antimicrobial agents. Dynamic in vitro models are valuable tools to examine the PK/PD and urodynamic variables associated with UTIs, while informing uropathogen susceptibility reporting, optimized dosing schedules, clinical trials and treatment guidelines.

Phage Therapy as a Novel Strategy in the Treatment of Urinary Tract Infections Caused by E. Coli

Urinary tract infections (UTIs) are regarded as one of the most common bacterial infections affecting millions of people, in all age groups, annually in the world. The major causative agent of complicated and uncomplicated UTIs are uropathogenic E. coli strains (UPECs). Huge problems with infections of this type are their chronicity and periodic recurrences. Other disadvantages that are associated with UTIs are accompanying complications and high costs of health care, systematically increasing resistance of uropathogens to routinely used antibiotics, as well as biofilm formation by them. This creates the need to develop new approaches for the prevention and treatment of UTIs, among which phage therapy has a dominant potential to eliminate uropathogens within urinary tract. Due to the growing interest in such therapy in the last decade, the bacteriophages (natural, genetically modified, engineered, or combined with antibiotics or disinfectants) represent an innovative antimicrobial alternative and a strategy for managing the resistance of uropathogenic microorganisms and controlling UTIs.