Urinary tract infections: epidemiology, mechanisms of infection and treatment options

Endolysin EN572-5 as an alternative to treat urinary tract infection caused by Streptococcus agalactiae

Streptococcus agalactiae (Group B Streptococcus, GBS) is an opportunistic pathogen causing urinary tract infection (UTI). Endolysin EN572-5 was identified in prophage KMB-572-E of the human isolate Streptococcus agalactiae KMB-572. The entire EN572-5 gene was cloned into an expression vector and the corresponding recombinant protein EN572-5 was expressed in Escherichia coli in a soluble form, isolated by affinity chromatography, and characterized. The isolated protein was highly active after 30 min incubation in a temperature range of - 20 °C to 37 °C and in a pH range of 5.5-8.0. The endolysin EN572-5 lytic activity was tested on different Streptococcus spp. and Lactobacillus spp. The enzyme lysed clinical GBS (n = 31/31) and different streptococci (n = 6/8), and also exhibited moderate lytic activity against UPEC (n = 4/4), but no lysis of beneficial vaginal lactobacilli (n = 4) was observed. The ability of EN572-5 to eliminate GBS during UTI was investigated using an in vitro model of UPSA. After the administration of 3 μM EN572-5, a nearly 3-log decrease of urine bacterial burden was detected within 3 h. To date, no studies have been published on the use of endolysins against S. agalactiae during UTI. KEY POINTS: • A lytic protein, EN572-5, from a prophage of a human GBS isolate has been identified. • This protein is easily produced, simple to prepare, and stable after lyophilization. • The bacteriolytic activity of EN572-5 was demonstrated for the first time in human urine.

A shared mechanism of multidrug resistance in laboratory-evolved uropathogenic Escherichia coli

The emergence of multidrug-resistant bacteria poses a significant threat to human health, necessitating a comprehensive understanding of their underlying mechanisms. Uropathogenic Escherichia coli (UPEC), the primary causative agent of urinary tract infections, is frequently associated with multidrug resistance and recurrent infections. To elucidate the mechanism of resistance of UPEC to beta-lactam antibiotics, we generated ampicillin-resistant UPEC strains through continuous exposure to low and high levels of ampicillin in the laboratory, referred to as Low AmpR and High AmpR, respectively. Whole-genome sequencing revealed that both Low and High AmpR strains contained mutations in the marR, acrR, and envZ genes. The High AmpR strain exhibited a single additional mutation in the nlpD gene. Using protein modeling and qRT-PCR analyses, we validated the contributions of each mutation in the identified genes to antibiotic resistance in the AmpR strains, including a decrease in membrane permeability, increased expression of multidrug efflux pump, and inhibition of cell lysis. Furthermore, the AmpR strain does not decrease the bacterial burden in the mouse bladder even after continuous antibiotic treatment in vivo, implicating the increasing difficulty in treating host infections caused by the AmpR strain. Interestingly, ampicillin-induced mutations also result in multidrug resistance in UPEC, suggesting a common mechanism by which bacteria acquire cross-resistance to other classes of antibiotics.

Manipulating the Gut Microbiome in Urinary Tract Infection-Prone Patients

Although antibiotics remain the mainstay of urinary tract infection treatment, many affected women can be caught in a vicious cycle in which antibiotics given to eradicate one infection predispose them to develop another. This effect is primarily mediated by disturbances in the gut microbiome that both directly enrich for uropathogenic overgrowth and induce systemic alterations in inflammation, tissue permeability, and metabolism that also decrease host resistance to infection recurrences. Here, we discuss nonantibiotic approaches to manipulating the gut microbiome to reverse the systemic consequences of antibiotics, including cranberry supplementation and other dietary approaches, probiotic administration, and fecal microbiota transplantation.

Management of Bacteriuria and Urinary Tract Infections in the Older Adult

Urinary tract infection (UTI) is one of the most frequent bacterial infections diagnosed in older adults and the most common reason for antibiotic prescriptions in nursing homes. Distinguishing between asymptomatic bacteriuria and UTI in older adults can be challenging and implementing a systematic approach to diagnosis using standard toolkits or algorithms is recommended for patients residing in post-acute and long-term care settings. This article reviews the pathophysiology, microbiology, diagnostic approach, treatment, and approaches to prophylaxis in the older adult.

A cynomolgus monkey E. coli urinary tract infection model confirms efficacy of new FimH vaccine candidates

The increase in urinary tract infections (UTI) caused by antibiotic-resistant Escherichia coli requires the development of new therapeutic agents and prophylactic vaccines. To evaluate the efficacy of new lead candidates, we implemented a cynomolgus macaque UTI challenge model that mimics human uncomplicated cystitis in response to transurethral challenge with a multidrug-resistant (MDR) E. coli serotype O25b ST131 isolate. E. coli fimbrial adhesin FimH and O-antigens are separately under clinical evaluation by others as vaccine candidates to prevent UTI and invasive urosepsis disease, respectively. Accordingly, we assessed the protective efficacy of three 50-µg intramuscular doses of a novel recombinant FimH antigen adjuvanted with liposomal QS21/MPLA compared with saline placebo in groups of nine animals. A third group was vaccinated with this FimH formulation in combination with 1 µg each of a four-valent mixture of serotype O1a, O2, O6, and O25b O-antigen CRM197 lattice glycoconjugates. Both vaccines elicited high levels of serum FimH IgG and adhesin blocking antibodies at the time of bacterial challenge and, for the combination group, O-antigen-specific antibodies. Following bacterial challenge, both vaccinated groups showed >200- and >700-fold reduction in bacteriuria at day 2 and day 7 post-infection compared with placebo, respectively. In parallel, both vaccines significantly reduced levels of inflammatory biomarkers IL-8 and myeloperoxidase in the urine at day 2 post-infection relative to placebo. Results provide preclinical proof-of-concept for the prevention of an MDR UTI infection by these new vaccine formulations.

Overcoming challenges in the management of recurrent urinary tract infections

INTRODUCTION

Urinary tract infection (UTI) is a major global health concern. While acute UTIs can usually be effectively treated, recurrent UTIs (rUTIs) impact patients for years, causing significant morbidity and can become refractory to front-line antibiotics.

AREAS COVERED

This review discusses the risk factors associated with rUTI, current rUTI treatment paradigms, prophylactic strategies, and challenges in rUTI diagnostics. We specifically discuss common risk factors for rUTI, including biological sex, age, menopause status, and diabetes mellitus. We also review recently available evidence for commonly used treatments, from oral antibiotic therapy to intravesical antimicrobials, electrofulguration of chronic cystitis, and the last-resort treatment, cystectomy. We discuss the most current literature evaluating prophylactic strategies for rUTI including long-term antibiotic prophylaxis, estrogen hormone therapy, and dietary supplements. Finally, we address the important role of UTI diagnostics in effective rUTI management and review the strengths and limitations of both current and emerging UTI diagnostic platforms as well as their ability to operate at point-of-care.

EXPERT OPINION

We discuss the current challenges faced by clinicians in managing rUTI in women and the steps that should be taken so that clinicians, scientists, and patients can work together to better understand the disease and develop better strategies for its management.

Investigation of Citrobacter freundii clinical isolates in a Chinese hospital during 2020-2022 revealed genomic characterization of an extremely drug-resistant C. freundii ST257 clinical strain GMU8049 co-carrying blaNDM-1 and a novel blaCMY variant

The emergence of multidrug-resistant Citrobacter freundii poses a significant threat to public health. C. freundii isolates were collected from clinical patients in a Chinese hospital during 2020-2022. An unusual strain, GMU8049, was not susceptible to any of the antibiotics tested, including the novel β-lactam/β-lactamase inhibitor combination ceftazidime-avibactam. Whole-genome sequencing (WGS) revealed that GMU8049 harbors a circular chromosome belonging to the rare ST257 and an IncX3 resistance plasmid. Genomic analysis revealed the coexistence of two β-lactamase genes, including plasmid-mediated blaNDM-1 and chromosomal blaCMY encoding a novel CMY variant, combined with an outer membrane porin deficiency, which may account for the extreme resistance to β-lactams. Conjugation experiment confirmed that the blaNDM-1 resistance gene located on pGMU8049 could be successfully transferred to Escherichia coli EC600. The novel CMY variant had an amino acid substitution at position 106 (N106S) compared to the closely related CMY-51. Additionally, a GMU8049-specific truncation in an OmpK37 variant that produces a premature stop codon. Moreover, a variety of chromosome-located efflux pump coding genes and virulence-related genes were also identified. Analysis of strain GMU8049 in the context of other C. freundii strains reveals an open pan-genome and the presence of mobile genetic elements that can mediate horizontal gene transfer of antimicrobial resistance and virulence genes. Our work provides comprehensive insights into the genetic mechanisms of highly resistant C. freundii, highlighting the importance of genomic surveillance of this opportunistic pathogen as a high-risk population for emerging resistance and pathogenicity.IMPORTANCEEmerging pathogens exhibiting multi-, extremely, and pan-drug resistance are a major concern for hospitalized patients and the healthcare community due to limited antimicrobial treatment options and the potential for spread. Genomic technologies have enabled clinical surveillance of emerging pathogens and modeling of the evolution and transmission of antimicrobial resistance and virulence. Here, we report the genomic characterization of an extremely drug-resistant ST257 Citrobacter freundii clinical isolate. Genomic analysis of GMU8049 with a rare ST type and unusual phenotypes can provide information on how this extremely resistant clinical isolate has evolved, including the acquisition of blaNDM-1 via the IncX3 plasmid and accumulation through chromosomal mutations leading to a novel CMY variant and deficiency of the outer membrane porin OmpK37. Our work highlights that the emergence of extremely resistant C. freundii poses a significant challenge to the treatment of clinical infections. Therefore, great efforts must be made to specifically monitor this opportunistic pathogen.

Incidence and Recurrence of Urinary Tract Infections Caused by Uropathogenic Escherichia coli: A Retrospective Cohort Study

Purpose

Urinary tract infections (UTIs) are among the most common bacterial infections, with uropathogenic Escherichia coli (UPEC) as the main etiologic agent of uncomplicated UTIs (uUTIs). The prevalence of uUTis caused by organisms with antimicrobial resistance (AMR) is increasing worldwide, complexifying the disease management and increasing the risk of complications. In efforts to develop new strategies for uUTI prevention, it is imperative to understand factors associated with the occurrence of new episodes.

Patients and Methods

This retrospective cohort study aimed to assess the incidence of uUTIs caused by UPEC (UPEC-uUTIs) or unknown etiology (untested uUTIs) in adults aged ≥18 years receiving care in a San Francisco healthcare system.

Results

During 2014-2019, 1087 UPEC-uUTI and 4106 untested uUTI cases were documented, of which 324 (29.8%; 95% confidence interval: 27.1%-32.6%) and 1030 (25.1%; 95% confidence interval: 23.8%-26.4%) were followed by ≥1 new episode of uUTI within 12 months. In the UPEC-uUTI cohort, male gender, diagnosis of diabetes mellitus, and prior uUTI were risk factors for new episodes of uUTI. At the time of first UPEC-uUTI diagnosis, antimicrobial prescriptions were retrieved for 41.1% of cases. When tested, AMR was most frequently reported for trimethoprim/sulfamethoxazole or trimethoprim/sulfamethoxazole prescribed with other antimicrobials.

Conclusion

Our study provides important information on the incidence and risk of repeated episodes of uUTIs, as well as on AMR related to them.

Pseudomonas aeruginosa kills Staphylococcus aureus in a polyphosphate-dependent manner

Due to their frequent coexistence in many polymicrobial infections, including in patients with cystic fibrosis or burn/chronic wounds, many studies have investigated the mechanistic details of the interaction between the opportunistic pathogens Pseudomonas aeruginosa and Staphylococcus aureus. P. aeruginosa rapidly outcompetes S. aureus under in vitro cocultivation conditions, which is mediated by several of P. aeruginosa's virulence factors. Here, we report that polyphosphate (polyP), an efficient stress defense system and virulence factor in P. aeruginosa, plays a role in the pathogen's ability to inhibit and kill S. aureus in a contact-independent manner. We show that P. aeruginosa cells characterized by low polyP levels are less detrimental to S. aureus growth and survival while the Gram-positive pathogen is significantly more compromised by the presence of P. aeruginosa cells that produce high levels of polyP. The polyP-dependent phenotype of P. aeruginosa-mediated killing of S. aureus could at least in part be direct, as polyP was detected in the spent media and causes significant damage to the S. aureus cell envelope. However, more likely is that polyP's effects are indirect through modulating the production of one of P. aeruginosa's virulence factors, pyocyanin. We show that pyocyanin production in P. aeruginosa occurs polyP-dependently and harms S. aureus through membrane damage and potentially the generation of reactive oxygen species, resulting in the increased expression of antioxidant enzymes. In summary, our study adds a new component to the list of biomolecules that the Gram-negative pathogen P. aeruginosa generates to compete with S. aureus for resources.IMPORTANCEHow do interactions between microorganisms shape the course of polymicrobial infections? Previous studies have provided evidence that the two opportunistic pathogens Pseudomonas aeruginosa and Staphylococcus aureus generate molecules that modulate their interaction with potentially significant impact on disease outcomes. Our study identified the biopolymer polyphosphate (polyP) as a new effector molecule that impacts P. aeruginosa's interaction with S. aureus. We show that P. aeruginosa kills S. aureus in a polyP-dependent manner, which occurs primarily through the polyP-dependent production of the P. aeruginosa virulence factor pyocyanin. Our findings add a new role for polyP to an already extensive list of functions. A more in-depth understanding of how polyP influences interspecies interactions is critical, as targeting polyP synthesis in bacteria such as P. aeruginosa may have a significant impact on other microorganisms and potentially result in dynamic changes in the microbial composition.

Estrogen-stimulated uropathogenic E. coli mediate enhanced neutrophil responses

Urinary tract infection (UTI) is one of the most common bacterial infections worldwide and the most common cause is uropathogenic Escherichia coli (UPEC). Current research is mostly focused on how UPEC affects host factors, whereas the effect of host factors on UPEC is less studied. Our previous studies have shown that estrogen alters UPEC virulence. However, the effect of this altered UPEC virulence on neutrophils is unknown. The aim of the present study was to investigate how the altered UPEC virulence mediated by estrogen modulates neutrophil responses. We found that estradiol-stimulated CFT073 increased neutrophil phagocytosis, NETs formation and intracellular ROS production. We observed that the total ROS production from neutrophils was reduced by estradiol-stimulated CFT073. We also found that estradiol-stimulated CFT073 induced less cytotoxicity in neutrophils. Additionally, we found that several cytokines and chemokines like IL-8, IL-1β, CXCL6, MCP-1 and MCP-4 were increased upon estradiol-stimulated CFT073 infection. In conclusion, this study demonstrates that the estrogen-mediated alterations to UPEC virulence modulates neutrophil responses, most likely in a host-beneficial manner.

Ecological and evolutionary mechanisms driving within-patient emergence of antimicrobial resistance

The ecological and evolutionary mechanisms of antimicrobial resistance (AMR) emergence within patients and how these vary across bacterial infections are poorly understood. Increasingly widespread use of pathogen genome sequencing in the clinic enables a deeper understanding of these processes. In this Review, we explore the clinical evidence to support four major mechanisms of within-patient AMR emergence in bacteria: spontaneous resistance mutations; in situ horizontal gene transfer of resistance genes; selection of pre-existing resistance; and immigration of resistant lineages. Within-patient AMR emergence occurs across a wide range of host niches and bacterial species, but the importance of each mechanism varies between bacterial species and infection sites within the body. We identify potential drivers of such differences and discuss how ecological and evolutionary analysis could be embedded within clinical trials of antimicrobials, which are powerful but underused tools for understanding why these mechanisms vary between pathogens, infections and individuals. Ultimately, improving understanding of how host niche, bacterial species and antibiotic mode of action combine to govern the ecological and evolutionary mechanism of AMR emergence in patients will enable more predictive and personalized diagnosis and antimicrobial therapies.

Global burden, trends, and cross-country inequalities of urinary tract infections in adolescents and young adults, 1990 to 2019

BACKGROUND

Limited studies have evaluated the global burden, trends, and cross-country inequalities for urinary tract infections (UTIs) in adolescents and young adults (AYAs).

METHODS

Age-standardized incidence rate, age-standardized mortality rate, and age-standardized Disability-Adjusted Life Years (DALYs) rate were used to describe the UTI burden. The estimated annual percentage changes were calculated to evaluate the temporal trends from 1990 to 2019. The slope index of inequality and concentration index were utilized to quantify the distributive inequalities.

RESULTS

From 1990 to 2019, a significant increase in age-standardized incidence rate (estimated annual percentage change =0.22%, 95% confidence interval 0.19%-0.26%) was found for UTIs in AYAs, and the increasing trend was more pronounced in males than females. Significant decreases in age-standardized mortality rate and age-standardized DALY rate were found in females but not in males. The slope index of inequality changed from 21.80 DALYs per 100,000 in 1990 to 20.91 DALYs per 100,000 in 2019 for UTIs in AYAs. Moreover, the concentration index showed -0.23 in 1990 and -0.14 in 2019.

DISCUSSION

Countries with lower sociodemographic development levels shouldered a disproportionately higher UTI burden.

CONCLUSIONS

UTIs remain an ongoing health burden for AYAs globally, with substantial heterogeneities found across countries, sex, and age groups.

Hydroxyproline increases inflammation and Uropathogenic E. coli (UPEC) infection in female rats

Calcium oxalate (CaOx) kidney stones may be associated with urinary tract infections (UTIs). However, the mechanisms for this association are not well-established. The objective of this study was to investigate the effect of oxalate on immunity and UTI development in vivo. Female Sprague-Dawley rats were fed a control diet for 3 days before continuing this diet or starting a 5% Hydroxy-L-proline diet (HLP; oxalate precursor) for 7 days. Rats were subsequently infected transurethrally with Uropathogenic E. coli (UPEC, a bacterium that causes UTI) and sacrificed 3 days later. Urine, blood, kidney, and bladder samples were collected. Urinary oxalate levels, renal CaOx crystal deposition, inflammatory markers, and the bacterial load were assessed using ion chromatography-mass spectrometry, immunohistochemistry, qRT-PCR, western blotting, enzyme-linked immunosorbent assays, or colony forming unit assays. Animals fed HLP and infected with UPEC had a significant increase in urinary oxalate levels, renal CaOx deposition, pro-inflammatory macrophages, pro-inflammatory cytokines, and bacterial loads compared to animals fed the control diet with UPEC infection. In addition, HLP-fed animals had significantly reduced anti-inflammatory renal macrophages and anti-inflammatory cytokine levels in their plasma, urine, and kidneys. These findings suggest that oxalate may play a novel role in the propagation of UTI development.

Enhanced antifouling and anti-swarming properties poly (sulfobetaine methacrylate-co-2-hydroxy-3-phenoxypropyl acrylate) hydrogel coatings for urinary catheters

Catheter-associated urinary tract infection (CAUTI) remains an unsolved challenge to date, particularly with the emergence and rapid spread of antimicrobial-resistant bacterial pathogens. Despite extensive research, a catheter coating that can offer intrinsic resistance to host protein deposition, bacterial biofilm formation, and swarming is still urgently required. Zwitterionic hydrogel coatings due to their superior lubricity and antifouling properties represent a promising candidate, but their weak mechanical stability in water and poor resistance to bacterial swarming migration limit their application in urinary catheters for infection control. In this research, we describe the fabrication of a multifunctional catheter coating by copolymerizing zwitterionic sulfobetaine methacrylate (SBMA) polymers and a swarming inhibitor material, 2-hydroxy-3-phenoxypropyl acrylate (HPA). The introduction of polyHPA (PHPA) effectively impeded the uncontrolled swelling behavior of the zwitterionic PSBMA hydrogel, resulting in enhanced mechanical stability. Moreover, the copolymer coating retains the antifouling and anti-swarming properties of the homopolymers when challenged with fibrinogen, Escherichia coli, and Proteus mirabilis. The HPA content significantly correlated with its anti-adhesion activity against fibrinogen and biofilm, and the coating with an SBMA: HPA monomer feed molar ratio of 4:1 showed the best antifouling activity, reducing fibrinogen deposition by about 40 % and biofilm coverage by around fourfold compared to the uncoated polydimethylsiloxane (PDMS) surface. Furthermore, the copolymer coating also exhibited no cytotoxicity, suggesting it as a promising catheter coating for preventing CAUTI.

"Urinary tract infection: Conventional testing to developing Technologies"

Urinary tract infections (UTIs) present an escalating global health concern, precipitating increased hospitalizations and antibiotic utilization, thereby fostering the emergence of antimicrobial resistance. Current diagnostic modalities exhibit protracted timelines and substantial financial burdens, necessitating specialized infrastructures. Addressing these impediments mandates the development of a precise diagnostic paradigm to expedite identification and augment antibiotic stewardship. The application of biosensors, recognized for their transformative efficacy, emerges as a promising resolution. Recent strides in biosensor technologies have introduced pioneering methodologies, yielding pertinent biosensors and integrated systems with significant implications for point-of-care applications. This review delves into historical perspectives, furnishing a comprehensive delineation of advancements in UTI diagnostics, disease etiology, and biomarkers, underscoring the potential merits of these innovations for optimizing patient care.

Enterococcus faecalis: an overlooked cell invader

SUMMARYEnterococcus faecalis and Enterococcus faecium are human pathobionts that exhibit a dual lifestyle as commensal and pathogenic bacteria. The pathogenic lifestyle is associated with specific conditions involving host susceptibility and intestinal overgrowth or the use of a medical device. Although the virulence of E. faecium appears to benefit from its antimicrobial resistance, E. faecalis is recognized for its higher pathogenic potential. E. faecalis has long been considered a predominantly extracellular pathogen; it adheres to and is taken up by a wide range of mammalian cells, albeit with less efficiency than classical intracellular enteropathogens. Carbohydrate structures, rather than proteinaceous moieties, are likely to be primarily involved in the adhesion of E. faecalis to epithelial cells. Consistently, few adhesins have been implicated in the adhesion of E. faecalis to epithelial cells. On the host side, very little is known about cognate receptors, except for the role of glycosaminoglycans during macrophage infection. Several lines of evidence indicate that E. faecalis internalization may involve a zipper-like mechanism as well as a macropinocytosis pathway. Conversely, E. faecalis can use several strategies to prevent engulfment in phagocytes. However, the bacterial and host mechanisms underlying cell infection by E. faecalis are still in their infancy. The most recent striking finding is the existence of an intracellular lifestyle where E. faecalis can replicate within a variety of host cells. In this review, we summarize and discuss the current knowledge of E. faecalis-host cell interactions and argue on the need for further mechanistic studies to prevent or reduce infections.

Comprehensive insights into UTIs: from pathophysiology to precision diagnosis and management

Urinary tract infections (UTIs) are the second most common infectious disease, predominantly impacting women with 150 million individuals affected globally. It increases the socio-economic burden of society and is mainly caused by Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Enterobacter spp., and Staphylococcus spp. The severity of the infection correlates with the host factors varying from acute to chronic infections. Even with a high incidence rate, the diagnosis is mainly based on the symptoms, dipstick analysis, and culture analysis, which are time-consuming, labour-intensive, and lacking sensitivity and specificity. During this period, medical professionals prescribe empirical antibiotics, which may increase the antimicrobial resistance rate. Timely and precise UTI diagnosis is essential for addressing antibiotic resistance and improving overall quality of life. In response to these challenges, new techniques are emerging. The review provides a comprehensive overview of the global burden of UTIs, associated risk factors, implicated organisms, traditional and innovative diagnostic methods, and approaches to UTI treatment and prevention.

Conformational ensembles in Klebsiella pneumoniae FimH impact uropathogenesis

Klebsiella pneumoniae is an important pathogen causing difficult-to-treat urinary tract infections (UTIs). Over 1.5 million women per year suffer from recurrent UTI, reducing quality of life and causing substantial morbidity and mortality, especially in the hospital setting. Uropathogenic E. coli (UPEC) is the most prevalent cause of UTI. Like UPEC, K. pneumoniae relies on type 1 pili, tipped with the mannose-binding adhesin FimH, to cause cystitis. However, K. pneumoniae FimH is a poor binder of mannose, despite a mannose-binding pocket identical to UPEC FimH. FimH is composed of two domains that are in an equilibrium between tense (low-affinity) and relaxed (high-affinity) conformations. Substantial interdomain interactions in the tense conformation yield a low-affinity, deformed mannose-binding pocket, while domain-domain interactions are broken in the relaxed state, resulting in a high-affinity binding pocket. Using crystallography, we identified the structural basis by which domain-domain interactions direct the conformational equilibrium of K. pneumoniae FimH, which is strongly shifted toward the low-affinity tense state. Removal of the pilin domain restores mannose binding to the lectin domain, thus showing that poor mannose binding by K. pneumoniae FimH is not an inherent feature of the mannose-binding pocket. Phylogenetic analyses of K. pneumoniae genomes found that FimH sequences are highly conserved. However, we surveyed a collection of K. pneumoniae isolates from patients with long-term indwelling catheters and identified isolates that possessed relaxed higher-binding FimH variants, which increased K. pneumoniae fitness in bladder infection models, suggesting that long-term residence within the urinary tract may select for higher-binding FimH variants.

Potential of silver nanoparticles synthesized from Justicia adhatoda metabolites for inhibiting biofilm on urinary catheters

In the present study, we investigated the anti-biofilm effect of urinary catheters fabricated with biogenic nanoparticles synthesized from metabolites of Justicia adhatoda under in vitro conditions against human pathogenic bacteria. Silver nanoparticles were synthesized in the reaction mixture composed of 2 % w/v of 0.1 M of precursor (silver nitrate) and 0.2 g of the metabolites obtained from ethanolic extract of Justicia adhatoda. Characterization of the nanoparticles was done by UV visible spectroscopy, fourier infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X ray diffraction (XRD) to confirm the structural and functional properties. Primary conformation of nanoparticles synthesis by UV visible spectroscopy revealed the notable absorption spectra at 425 nm with a wavelength shift around 450 nm, likely due to surface plasmon resonance excitation. SEM analysis showed spherical, monodisperse, nano scale particles with a size range of 50-60 nm. Crystaline phase of the synthesized nanoparticles was confirmed by x ray diffraction studies which showed the distinct peaks at (2θ) 27.90, 32.20, 46.30, 54.40, and 67.40, corresponding to (111), (200), (220), (222), and (311) planes of nano scale silver. The biocompatibility of these nanoparticles was assessed through zebrafish embryonic toxicity study which showed more than 90 % of embryos were alive and healthy. No marked changes on the blood cells also confirmed best hemocompatibility of the nanoparticles. Synthesized nanoparticles thus obtained were fabricated on the urinary catheter and the fabrication was confirmed by FTIR and SEM analysis. Notable changes in the absorption peaks, uniform coating and embedding of silver nanoparticles studied by FTIR and SEM analysis confirmed the fabrication of silver nanoparticles. The coated catheters demonstrated significant antibacterial activity against pathogenic bacterial strains, including E. coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. Anti-biofilm studies, conducted using a modified microtiter plate crystal violet assay, revealed effective inhibition of both bacterial adhesion and biofilm development. 85 % of biofilm inhibition was recorded against both the tested strains. The coating method presented in this study shows promise for enhancing infection resistance in commonly used medical devices like urinary catheters, thus addressing device-associated infections.

Qualitative Profiling, Antioxidant and Antimicrobial Activities of Polar and Nonpolar Basil Extracts

Basil (Ocimum basilicum L.) is a widely used culinary herb. In this study, ethanol, dichloromethane, and sunflower oil were used separately as solvents with distinct polarities for the extraction of basil aerial parts to simulate the different polarity conditions in domestic food processing. The oil extract (OE) was re-extracted with acetonitrile, and the chemical composition, antioxidant potential, and antimicrobial activities of the ethanol (EE), dichloromethane (DCME), and acetonitrile (ACNE) extracts were determined. A total of 109 compounds were tentatively identified in EE, DCME, and ACNE by HPLC-DAD/ESI-ToF-MS. Fatty acids were present in all extracts. Phenolic acids and flavonoids dominated in EE. DCME was characterised by triterpenoid acids, while diterpenoids were mainly found in ACNE. The extracts were analysed for their antioxidant capacity using the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) assay. EE and DCME showed significant radical scavenging potential. Antimicrobial activity was explored in eight bacterial, two yeast, and one fungal species. All extracts exhibited high antifungal activity, comparable to or better than that of the commercial drug nistatin. Antibacterial activities were notable for EE and ACNE, while DCME showed no activity against bacteria in the applied concentration ranges. The different polarities of the solvents led to distinctive phytochemical compositions and bioactivities in the extracts.

Fabrication of Aluminum Foil Integrated Pegylated Gold Nanoparticle Surface-Enhanced Raman Scattering Substrate for the Detection and Classification of Uropathogenic Bacteria

Rapid detection and classification of pathogenic microbes for food hygiene, healthcare, environmental contamination, and chemical and biological exposures remain a major challenge due to nonavailability of fast and accurate detection methods. The delay in clinical diagnosis of the most frequent bacterial infections, particularly urinary tract infections (UTIs), which affect about half of the population at least once in their lifetime, can be fatal if not detected and treated appropriately. In this work, we have fabricated aluminum (Al) foil integrated pegylated gold nanoparticles (AuNPs) as a potential surface-enhanced Raman scattering (SERS) substrate, which is used for the detection and classification of uropathogens, namely, E. coli, S. aureus, and P. aeruginosa directly from the culture without any pretreatment. The substrate is first drop cast with bacterial pellets and then pegylated AuNPs, and the interaction of two on Al foil base gives identifiable characteristic Raman peaks with good reproducibility. With the use of chemometric methods such as principal component analysis (PCA), the Al foil-based SERS substrate offers a quick, effective detection and classification of three strains of UTI bacteria with the least bacterial concentration (105 cells mL-1) necessary for clinical diagnosis. In addition, this substrate was able to detect E. coli positive clinical samples by giving SERS fingerprint information directly from centrifuged urine samples within minutes. The stability of pegylated AuNPs provides for its application at the point of care with rapid and easy detection of uropathogens as well as the possibility of advancement in healthcare applications.

Detection of mecA-mediated methicillin resistance and evaluation of disk-diffusion antimicrobial susceptibility characteristics of Staphylococcus saprophyticus isolates from geographically diverse locations: Staphylococcus saprophyticus antibiotic susceptibility testing

Staphylococcus saprophyticus, a common uropathogen, is usually susceptible to urine-concentrating antimicrobials, so routine AST is not recommended by CLSI. Our study evaluated the antimicrobial resistance profiles of 277 S. saprophyticus isolates from North America and a globally diverse cohort. Notably, 24% (67/277) of our isolates come from non-urinary sources. AST was performed against 12 antimicrobials using standard disk diffusion, PCR for mecA and mecC, PBP2a production assays, and cefinase. 5% (13/277) of isolates were mecA positive and cefinase positive, 63% (176/277) were mecA negative but cefinase positive, 4% (11/277) were mecA positive but cefinase negative, and 28% (77/277) were mecA and cefinase negative. All (277/277) isolates were susceptible to delafloxacin, ciprofloxacin, rifampin, linezolid, and nitrofurantoin and 95% (262/277) were susceptible to trimethoprim-sulfamethoxazole. Our results showed that regardless of using CLSI or EUCAST breakpoints oxacillin had low categorical agreement for mecA presence, making it unsuitable for surrogate testing, while cefoxitin disk diffusion had high very major error rate. If possible, PBP2a or mecA testing is recommended for guiding therapy for non-urinary infections. Our work supports CLSI guidelines on routine susceptibility to urinary tract antibiotics.

Comprehensive Genomic Analysis of Uropathogenic E. coli: Virulence Factors, Antimicrobial Resistance, and Mobile Genetic Elements

Our whole-genome sequencing analysis of sixteen uropathogenic E. coli isolates revealed a concerning picture of multidrug resistance and potentially virulent bacteria. All isolates belonged to four distinct clonal groups, with the highly prevalent ST131 lineage being associated with extensive antibiotic resistance and virulence factors. Notably, all isolates exhibited multidrug resistance, with some resistant to as many as 12 antibiotics. Fluoroquinolone resistance stemmed primarily from efflux pumps and mutations in gyrase and topoisomerase genes. Additionally, we identified genes encoding resistance to extended-spectrum cephalosporins, trimethoprim/sulfamethoxazole, and various heavy metals. The presence of diverse plasmids and phages suggests the potential for horizontal gene transfer and the dissemination of virulence factors. All isolates harbored genomic islands containing virulence factors associated with adhesion, biofilm formation, and invasion. Genes essential for iron acquisition, flagella biosynthesis, secretion systems, and toxin production were also prevalent. Adding further complexity to understanding the isolates' genetic makeup, we identified CRISPR-Cas systems. This study underscores the need for continued genomic surveillance in understanding the pathogenic mechanisms and resistance profiles of uropathogenic E. coli to aid in developing targeted therapeutic strategies.

Activity of mecillinam against USA urinary tract clinical isolates from 2017 to 2020 including isolates resistant to comparator antibiotics

OBJECTIVES

To support the clinical development of mecillinam and pivmecillinam in the United States for the treatment of complicated and uncomplicated urinary tract infections (UTIs), this study investigated the activity of mecillinam compared with other antibiotics against Enterobacterales isolates from patients with UTIs in the United States during 2017 to 2020. Mecillinam is a first-in-class amidinopenicillin antibiotic, being the only β-lactam to exert its antibacterial activity through exclusive binding to penicillin-binding protein 2. Pivmecillinam is the oral prodrug of mecillinam and is recommended as a first-line therapy by the Infectious Disease Society of America guidelines for uncomplicated UTIs and is approved for the treatment of uncomplicated UTIs in Europe, Canada, and the United States.

METHODS

A total of 3303 isolates were collected and antimicrobial susceptibility determined according to Clinical Laboratory and Standards Institute (CLSI) guidelines.

RESULTS

Susceptibility was highest for fosfomycin (97.1% susceptible) and mecillinam (94.9% susceptible). Against extended-spectrum beta-lactamase (ESBL)-positive bacteria susceptibilities were highest for mecillinam (98.2% susceptible) and fosfomycin (97.3% susceptible) and against ESBL-positive K. pneumoniae only mecillinam and fosfomycin had > 80% susceptibility. Resistance to comparator antibiotics was highest for trimethoprim-sulfamethoxazole (27.1%), followed by ciprofloxacin (19.3%), ceftriaxone (19.2%), and nitrofurantoin (12.1%). Multi-drug-resistant isolates were most susceptible to mecillinam and fosfomycin.

CONCLUSION

The data further support the clinical development and clinical utility of mecillinam. © 2024 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.

Predictive performance of urinalysis for urine culture results according to causative microorganisms: an integrated analysis with artificial intelligence

Urinary tract infections (UTIs) are pervasive and prevalent in both community and hospital settings. Recent trends in the changes of the causative microorganisms in these infections could affect the effectiveness of urinalysis (UA). We aimed to evaluate the predictive performance of UA for urinary culture test results according to the causative microorganisms. In addition, UA results were integrated with artificial intelligence (AI) methods to improve the predictive power. A total of 360,376 suspected UTI patients were enrolled from two university hospitals and one commercial laboratory. To ensure broad model applicability, only a limited range of clinical data available from commercial laboratories was used in the analyses. Overall, 53,408 (14.8%) patients were identified as having a positive urine culture. Among the UA tests, the combination of leukocyte esterase and nitrite tests showed the highest area under the curve (AUROC, 0.766; 95% CI, 0.764-0.768) for predicting urine culture positivity but performed poorly for Gram-positive bacteriuria (0.642; 0.637-0.647). The application of an AI model improved the predictive power of the model for urine culture results to an AUROC of 0.872 (0.870-0.875), and the model showed superior performance metrics not only for Gram-negative bacteriuria (0.901; 0.899-0.902) but also for Gram-positive bacteriuria (0.745; 0.740-0.749) and funguria (0.872; 0.865-0.879). As the prevalence of non-Escherichia coli-caused UTIs increases, the performance of UA in predicting UTIs could be compromised. The addition of AI technologies has shown potential for improving the predictive performance of UA for urine culture results.IMPORTANCEUA had good performance in predicting urine culture results caused by Gram-negative bacteria, especially for Escherichia coli and Pseudomonas aeruginosa bacteriuria, but had limitations in predicting urine culture results caused by Gram-positive bacteria, including Streptococcus agalactiae and Enterococcus faecalis. We developed and externally validated an AI model incorporating minimal demographic information of patients (age and sex) and laboratory data for UA, complete blood count, and serum creatinine concentrations. The AI model exhibited improved performance in predicting urine culture results across all the causative microorganisms, including Gram-positive bacteria, Gram-negative bacteria, and fungi.

Draft genomes of Neisseria perflava UMB0578, Proteus mirabilis UMB8339, and Enterococcus faecalis UMB7967 isolated from urine samples

The urinary tract of females harbors a variety of microorganisms, both for those with and without symptoms. Here, we present the draft genome sequences of three isolates from urine samples-Neisseria perflava UMB0578, Proteus mirabilis UMB8339, and Enterococcus faecalis UMB7967.

Enterococcal-host interactions in the gastrointestinal tract and beyond

The gastrointestinal tract (GIT) is typically considered the natural niche of enterococci. However, these bacteria also inhabit extraintestinal tissues, where they can disrupt organ physiology and cause life-threatening infections. Here, we discuss how enterococci, primarily Enterococcus faecalis, interact with the intestine and other host anatomical locations such as the oral cavity, heart, liver, kidney, and vaginal tract. The metabolic flexibility of these bacteria allows them to quickly adapt to new environments, promoting their persistence in diverse tissues. In transitioning from commensals to pathogens, enterococci must overcome harsh conditions such as nutrient competition, exposure to antimicrobials, and immune pressure. Therefore, enterococci have evolved multiple mechanisms to adhere, colonize, persist, and endure these challenges in the host. This review provides a comprehensive overview of how enterococci interact with diverse host cells and tissues across multiple organ systems, highlighting the key molecular pathways that mediate enterococcal adaptation, persistence, and pathogenic behavior.

Relationship between the Presence of Human Papillomavirus in the Female Urethra and Recurrent Urinary Tract Infections

Introduction: Recurrent urinary tract infections (rUTIs) are highly prevalent health issues among women, significantly impacting their quality of life. Urethral pain or urethritis can arise from infectious or non-infectious origins. The presence of Human Papillomavirus (HPV) in the urogenital tract has been associated with high-risk sexual behaviors, but its presence in the female urethra without such behaviors has not been thoroughly investigated. Objectives: The study aims to determine the presence of HPV in the urethra of women with recurrent urinary tract infections (rUTIs) and concomitant urethral syndrome and to compare the clinical and microbiological characteristics of women with and without urethral HPV, specifically focusing on those without high-risk sexual behaviors. Methods: This prospective multicenter study included 138 women over 18 years old with rUTIs and concomitant urethral pain syndrome. High-risk sexual behaviors, sexually transmitted infections, and vaginitis were set as exclusion criteria. Participants were divided into two groups: NHPV (n = 72) with no urethral HPV and HPV (n = 66) with urethral HPV presence. Variables analyzed included age, body mass index (BMI), follow-up duration, comorbidities, treatments, toxic habits, surgical history, main symptoms, urine sediment findings, and cultures from urine and vaginal exudate. HPV genotyping was also performed. Descriptive statistics were used, along with Student's t-test, Chi-square, Fisher's exact test, ANOVA, and multivariate cluster analysis. Results: The NHPV group was older on average (48.75 years) compared to the HPV group (39.09 years). The HPV group had a longer follow-up period (2634 days vs. 1975 days in NHPV). Urinary incontinence was significantly more common in NHPV (63.89%) compared to HPV (18.18%) (p = 0.001). HPV-positive women had a higher prevalence of verrucous lesions in the vaginal introitus (64% vs. 8% in NHPV). Additionally, the HPV group showed higher rates of pyuria (27.27%), vaginal Candida albicans (36.26%), and positive urine cultures for Escherichia coli (47.83%), Enterococcus faecalis (36.36%), and Klebsiella pneumoniae (21.74%). No significant differences were observed between the groups concerning BMI, smoking habits, diabetes, or the main symptom at consultation. The most common HPV genotypes identified were G35, G42, and G66 (each 27%). Multivariate analysis revealed that sensitivity to nitrofurantoin was the most significant variable in the HPV group (importance of 0.96), followed by fosfomycin (0.79), trimethoprim (0.79), and amoxicillin (0.71). Conclusions: HPV was present in the urethra of 47.8% of women with rUTIs and concomitant urethral syndrome who did not exhibit high-risk sexual behaviors. These women were younger and had a longer duration of symptoms compared to those without urethral HPV. The identification of Enterococcus faecalis, Escherichia coli, and Klebsiella pneumoniae was more common in the HPV group. The sensitivity of bacteria to nitrofurantoin and fosfomycin is crucial for the clinical management of these patients. The presence of urethral HPV should be considered in the evaluation and treatment of women with rUTIs and urethral syndrome.

Variability in Profiles and Prevalences of Gram-Negative Bacteria in Urinary Tract Infections: A Population-Based Analysis

Objective: An increase in antimicrobial resistance (AMR) is observed worldwide, partly due to the overuse and misuse of antibiotics, which are ineffective in certain population subgroups. This negatively impacts both the healthcare system and patients. Our study aimed to investigate the current AMR profiles for the most commonly used antibiotics in treating urinary tract infections (UTIs) caused by gram-negative bacteria (GNB) across different age and gender subpopulations. By doing so, we provide valuable information for doctors managing prophylactic and empiric therapeutic treatments. Materials and Methods: We retrospectively analysed over 650,000 urine cultures collected in the Microbiology Department of a referral university hospital in Southern England from January 2014 to December 2022. A population-based analysis for subgroups was performed to rule out differences in AMR patterns. Our report was recorded at UHS as an internal audit (UHS7670). Results: 146,867 cultures were found positive for GNB growth. Nitrofurantoin showed the best sensitivity patterns for all age subgroups (0.93% for patients aged ≤ 18; 1.22% for patients aged 19-40; 2.17% for patients aged 40-60; and 3.48% for patients aged > 60), regardless of gender (male: 6.37%, female: 2.59%). Ampicillin/amoxicillin and trimethoprim showed a poor AMR profile for all age groups (>55% and >28%, respectively) and genders (>60% and >28%, respectively). All the other tested antibiotics (cefalexin, cefotaxime, ceftazidime, ciprofloxacin, co-amoxiclav, gentamicin) showed an overall good profile for GNB resistance across all subgroups. For all antibiotics except trimethoprim, the risk of developing AMR was significantly higher in the male population. We also found that people aged over 60 had a higher risk of AMR compared to the other age groups for all antibiotics, with the exception of cefotaxime and co-amoxiclav. Conclusions: With an overall rise in resistance patterns for GNB-related UTIs, certain antibiotics-particularly ampicillin/amoxicillin and trimethoprim-now exhibit very poor sensitivity profiles. However, antibiotics such as nitrofurantoin and gentamicin remain excellent options for empirically treating UTIs. It is important to note that AMR can vary across different populations, with higher resistance often found in elderly and male patients. Clinicians must stay informed about current guidelines and research to provide the best treatment options while minimizing the risk of further AMR development.

Urinary tract infections and risk of preterm birth: a systematic review and meta-analysis

This systematic review and meta-analysis assessed the association between urinary tract infections (UTIs) during pregnancy and the risk of preterm birth (PTB). We searched multiple databases for relevant observational studies, categorizing them as UTI-based (comparing PTB incidence in women with and without UTIs) or PTB-based (comparing UTI prevalence in women with and without PTB). Using a random-effects model in Stata software version 17.0, we estimated pooled and adjusted odds ratios (ORs) with 95% confidence intervals (CIs), and performed subgroup, sensitivity, and cumulative analyses to explore heterogeneity. In total, 30 studies comprising 32 datasets were included, involving a total of 249,810 cases and 2,626,985 healthy controls. The meta-analysis revealed a significant positive association between UTIs during pregnancy and PTB occurrence (OR, 1.92; 95% CI, 1.62-2.27). A sub-group analysis based on studies, the participants showed significant association in both PTB-based (OR, 2.01; 95% CI, 1.58-2.56) and UTI-based studies (OR, 1.79; 95% CI, 1.42-2.26). However, Egger's test indicated the presence of publication bias (p=0.020), and substantial heterogeneity was observed across the included studies (I2=96.6; p< 0.001). These findings emphasize the critical importance of early detection and effective management of UTIs in pregnant women to reduce the risk of PTB and its associated adverse outcomes. While the results highlight a robust link between UTIs during pregnancy and PTB risk, the potential influence of publication bias and substantial heterogeneity should be considered to interpret these findings. Further research is needed to better understand the underlying mechanisms and to develop targeted interventions for high-risk pregnant women.

Genomic insights into a Proteus mirabilis strain inducing avian cellulitis

Proteus mirabilis, a microorganism distributed in soil, water, and animals, is clinically known for causing urinary tract infections in humans. However, recent studies have linked it to skin infections in broiler chickens, termed avian cellulitis, which poses a threat to animal welfare. While Avian Pathogenic Escherichia coli (APEC) is the primary cause of avian cellulitis, few cases of P. mirabilis involvement are reported, raising questions about the factors facilitating such occurrences. This study employed a pan-genomic approach to investigate whether unique genes exist in P. mirabilis strains causing avian cellulitis. The genome of LBUEL-A33, a P. mirabilis strain known to cause this infection, was assembled, and compared with other P. mirabilis strains isolated from poultry and other sources. Additionally, in silico serogroup analysis was conducted. Results revealed numerous genes unique to the LBUEL-A33 strain. No function in cellulitis was identified for these genes, and in silico investigation of the virulence potential of LBUEL-A33's exclusive proteins proved inconclusive. These findings support that multiple factors are necessary for P. mirabilis to cause avian cellulitis. Furthermore, this species likely employs its own unique arsenal of virulence factors, as many identified mechanisms are analogous to those of E. coli. While antigenic gene clusters responsible for serogroups were identified, no clear trend was observed, and the gene cluster of LBUEL-A33 did not show homology with any sequenced Proteus serogroups. These results reinforce the understanding that this disease is multifactorial, necessitating further research to unravel the mechanisms and underpin the development of control and prevention strategies.

Urinary tract infection among people living with human immunodeficiency virus attending selected hospitals in Addis Ababa and Adama, central Ethiopia

Background

Urinary tract infections (UTIs) and antibacterial resistance (ABR) are important public health problems, but they are not well-studied among people living with human immunodeficiency virus (PLHIV) globally, especially in low-income countries. Therefore, it is important to regularly measure the extent of UTIs and ABR in the most susceptible populations. This study aimed to investigate the prevalence of UTIs, associated factors, bacterial causal agents, and their antibiotic susceptibility profile among PLHIV in central Ethiopia.

Methods

A hospital-based cross-sectional study was conducted to recruit 688 PLHIV by a simple random sampling method. Background information was gathered through interviews, while clinical information was gathered from recent information sheets of patient charts using organized, pretested, and validated study tools. Midstream urine was collected aseptically and transported to the Microbiology Laboratory of Aklilu Lemma Institute of Pathobiology within 4 h of collection, maintaining its cold chain. Standard conventional microbial culture methods and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry were used to identify the bacterial isolates at the species level. Kirby Bauer's disk diffusion method was used to determine the antibiotic susceptibility profile of the bacterial isolates based on the interpretation guidelines of the Clinical Laboratory Standard Institute. Logistic regression models were used to examine factors associated with the occurrence of UTIs among PLHIV attending selected hospitals in Addis Ababa, and Adama.

Results

Out of 688 PLHIVs involved in the current study, 144 (20.9%) were positive for UTIs, whereas the majority were asymptomatic for UTIs. In the multivariable logistic regression analysis, only HIV RNA ≥ 200 copies/ml [AOR = 12.24 (95% CI, 3.24, 46.20), p < 0.01] and being symptomatic for UTIs during the study period [AOR = 11.57 (95% CI, 5.83, 22.97), p < 0.01] were associated with the occurrence of UTIs. The dominant bacterial species isolated were Escherichia coli (E. coli; n = 65; 43%), followed by Enterococcus faecalis (E. faecalis; n = 16; 10.6%) and Klebsiella pneumoniae (K. pneumoniae; n = 11; 7.3%). Over half of the E. coli isolates were resistant to antibiotics such as gentamicin (GM; n = 44; 67.7%), amikacin (AN; n = 46; 70.8%), nalidixic acid (NA; n = 42; 64.6%), ciprofloxacin (CIP; n = 40; 61.5%), and azithromycin (AZM; n = 45; 69.2%). All of the K. pneumoniae isolates (n = 11; 100%), (n = 6; 54.5%), and (n = 7; 63.6%) were resistant to [amoxicillin as well as amoxicillin + clavulanic acid], ceftriaxone, and sulfamethoxazole + trimethoprim, respectively. All the Staphylococcus aureus (S. aureus) isolates were resistant to cefoxitin, which implies methicillin-resistant S. aureus (MRSA).

Conclusion

The high prevalence of UTIs and antibiotic resistance revealed in the current study needs public health interventions such as educating the population about preventive measures and the importance of early treatment of UTIs. Our findings also highlight the need to provide UTI screening services for PLHIV, and healthcare providers should adopt antibiotic stewardship programs to promote and ensure their appropriate and judicious use.

Drivers of virulence and antimicrobial resistance in Gram-negative bacteria in different settings: A genomic perspective

The human gut presents a complex ecosystem harboring trillions of microorganisms living in close association with each other and the host body. Any perturbation or imbalance of the normal gut microbiota may prove detrimental to human health. Enteric infections and treatment with antibiotics pose major threats to gut microbiota health. Recent genomics-driven research has provided insights into the transmission and evolutionary dynamics of major enteric pathogens such as Escherichia coli, Klebsiella pneumoniae, Vibrio cholerae, Helicobacter pylori and Salmonella spp. Studies entailing the identification of various dominant lineages of some of these organisms based on artificial intelligence and machine learning point to the possibility of a system for prediction of antimicrobial resistance (AMR) as some lineages have a higher propensity to acquire virulence and fitness advantages. This is pertinent in the light of emerging AMR being one of the immediate threats posed by pathogenic bacteria in the form of a multi-layered fitness manifesting as phenotypic drug resistance at the level of clinics and field settings. To develop a holistic or systems-level understanding of such devastating traits, present methodologies need to be advanced with the high throughput techniques integrating community and ecosystem/niche level data across different omics platforms. The next major challenge for public health epidemiologists is understanding the interactions and functioning of these pathogens at the community level, both in the gut and outside. This would provide new insights into the dimensions of enteric bacteria in different environments and niches and would have a plausible impact on infection control strategies in terms of tackling AMR. Hence, the aim of this review is to discuss virulence and AMR in Gram-negative pathogens, the spillover of AMR and methodological advancements aimed at addressing it through a unified One Health framework applicable to the farms, the environment, different clinical settings and the human gut.

The Urinary Microbiome Is a Potential Driver of Urinary Tract Pathology Through Multiple Mechanisms Including Deglucuronidation and DNA Damage

Chronic urinary infection may have implications for disease because of reactivation of toxins in the urine or damage to bladder defences. Exploration of these possibilities requires a scrupulous scientific approach.

Micro-flow cell washing technique combined with single-cell Raman spectroscopy for rapid and automatic antimicrobial susceptibility test of pathogen in urine

Facing the rapid spread of antimicrobial resistance, methods based on single-cell Raman spectroscopy have proven their advances in reducing the turn-around time (TAT) of antimicrobial susceptibility tests (AST). However, the Raman-based methods are still hindered by the prolonged centrifugal cell washing procedure, which may require complex labor operation and induce high mechanical stress, resulting in a pretreatment time of over 1 h as well as a high cell-loss probability. In this study, we developed a micro-flow cell washing device and corresponding Raman-compatible washing chips, which were able to automatically remove the impurities in the samples, retain the bacterial cell and perform Raman spectra acquisition in situ. Results of washing the 5- and 10-μm polymethyl methacrylate (PMMA) microspheres showed that the novel technique achieved a successful removal of 99 % impurity and an 80 % particle retention rate after 6 to 10 cycles of washing. The micro-flow cell washing technique could complete the pretreatment for urine samples in a 96-well plate within 10 min, only taking 15 % of the handling time required by centrifugation. The AST profiles of urine sample spiked with E. coli 25922, E. faecalis 29212, and S. aureus 29213 obtained by the proposed Raman-based approach were found to be 100 % consistent with the results from broth micro-dilution while reducing the TAT to 3 h from several days which is required by the latter. Our study has demonstrated the micro-flow cell washing technique is a reliable, fast and compatible approach to replace centrifuge washing for sample pretreatment of Raman-AST and could be readily applied in clinical scenarios.

The role of bacterial size, shape and surface in macrophage engulfment of uropathogenic E. coli cells

Uropathogenic Escherichia coli (UPEC) can undergo extensive filamentation in the host during acute urinary tract infections (UTIs). It has been hypothesised that this morphological plasticity allows bacteria to avoid host immune responses such as macrophage engulfment. However, it is still unclear what properties of filaments are important in macrophage-bacteria interactions. The aim of this work was to investigate the contribution of bacterial biophysical parameters, such as cell size and shape, and physiological parameters, such as cell surface and the environment, to macrophage engulfment efficiency. Viable, reversible filaments of known lengths and volumes were produced in the UPEC strain UTI89 using a variety of methods, including exposure to cell-wall targeting antibiotics, genetic manipulation and isolation from an in vitro human bladder cell model. Quantification of the engulfment ability of macrophages using gentamicin-protection assays and fluorescence microscopy demonstrated that the ability of filaments to avoid macrophage engulfment is dependent on a combination of size (length and volume), shape, cell surface and external environmental factors. UTI89 filamentation and macrophage engulfment efficiency were also found to occur independently of the SOS-inducible filamentation genes, sulA and ymfM in both in vivo and in vitro models of infection. Compared to filaments formed via antibiotic inhibition of division, the infection-derived filaments were preferentially targeted by macrophages. With several strains of UPEC now resistant to current antibiotics, our work identifies the importance of bacterial physiological and morphological states during infection.

Discovery and characterisation of new phage targeting uropathogenic Escherichia coli

Antimicrobial resistance is an escalating threat with few new therapeutic options in the pipeline. Urinary tract infections (UTIs) are one of the most prevalent bacterial infections globally and are prone to becoming recurrent and antibiotic resistant. We discovered and characterized six novel Autographiviridae and Guernseyvirinae bacterial viruses (phage) against uropathogenic Escherichia coli (UPEC), a leading cause of UTIs. The phage genomes were between 39,471 bp - 45,233 bp, with 45.0%-51.0% GC%, and 57-84 predicted coding sequences per genome. We show that tail fiber domain structure, predicted host capsule type, and host antiphage repertoire correlate with phage host range. In vitro characterisation of phage cocktails showed synergistic improvement against a mixed UPEC strain population and when sequentially dosed. Together, these phage are a new set extending available treatments for UTI from UPEC, and phage vM_EcoM_SHAK9454 represents a promising candidate for further improvement through engineering.

Novel Insights on Group B Streptococcus in Pregnancy

Group B Streptococcus (GBS) is a frequent colonizer of the human genital and gastrointestinal tract. In pregnant or postpartum persons, colonization is often asymptomatic and can contribute to infectious morbidity in both the parturient and the newborn. The prevalence of invasive GBS disease has dramatically decreased over the past 3 decades. However, despite standardized clinical algorithms, GBS disease remains a public health concern. Our review summarizes the GBS bacteria pathophysiology, morbidity, management guidelines, and summarizes ongoing research. While novel testing and parturient vaccination are being explored, barriers exist, preventing guideline updates and widespread implementation.

Adjunctive intravesical EDTA-tromethamine treatment of a biofilm-associated recurrent Escherichia coli cystitis in a dog

A 15-month-old spayed female greater Swiss mountain dog was brought to our clinic because of relapsing episodes of urinary tract infection, present since her adoption at 2 mo of age. A diagnosis of chronic bacterial cystitis associated with an invasive, biofilm-forming uropathogenic Escherichia coli was made with bladder-wall histology and fluorescent in situ hybridization analysis. Local treatment with EDTA-tromethamine (EDTA-Tris) infusions along with parenteral cefquinome and prophylactic measures (Type-A proanthocyanidins and probiotics) coincided with clinical and bacterial remission. The dog has been free of clinical signs of urinary tract infection for >4 y. Biofilm-forming uropathogenic E. coli can cause chronic, recurrent cystitis due to low antibiotic efficacy and should be considered in cases of recurrent cystitis in dogs, especially in the absence of identified predisposing factors. This case report describes the diagnostic and therapeutic options that were used to manage a case of this type. Key clinical message: Fluorescent in situ hybridization analysis may be considered in the diagnosis of chronic bacterial cystitis in dogs, and intravesical instillations of EDTA-Tris may be helpful in managing such cases.

Prevention and Management of Infectious Complications in Retrograde Intrarenal Surgery: A Comprehensive Review

Retrograde intrarenal surgery (RIRS) is a minimally invasive procedure increasingly used to treat renal stones and other intrarenal pathologies due to its reduced risk of complications, shorter recovery time, and lower postoperative pain compared to more invasive surgical techniques. However, despite its advantages, RIRS is associated with a significant risk of infectious complications, ranging from simple urinary tract infections (UTIs) to severe systemic infections such as urosepsis, which can lead to increased morbidity, prolonged hospitalization, and, in severe cases, mortality. This review aims to summarize the current knowledge on preventing and managing infectious complications associated with RIRS. By exploring the pathophysiology of these infections, identifying patient and procedural risk factors, and evaluating evidence-based strategies for prevention and management, this review provides comprehensive insights into minimizing infection risks in RIRS. A thorough literature review was conducted, examining studies and clinical trials that address the incidence, risk factors, prevention strategies, and management protocols for infections in RIRS. This review also assesses current guidelines from professional organizations and recent infection control technologies and practices advancements. The review identifies multiple risk factors contributing to infections in RIRS, including patient-specific factors such as comorbidities and procedural factors like the duration of surgery and use of instrumentation. Effective prevention strategies include preoperative antibiotic prophylaxis, stringent aseptic techniques during surgery, and careful postoperative monitoring. The review also highlights the importance of a multidisciplinary approach involving urologists, infectious disease specialists, and microbiologists in managing complex cases of infection. Infectious complications remain a significant concern in RIRS, necessitating a comprehensive approach to prevention and management. By adhering to evidence-based guidelines and utilizing a multidisciplinary strategy, healthcare professionals can significantly reduce the incidence of infections, thereby improving patient outcomes and the overall safety of RIRS. Future research should focus on advancing infection control technologies and developing novel prophylactic and therapeutic approaches to further enhance the safety and effectiveness of RIRS.

Uropathogens and their antibiotic susceptibility patterns among diabetic patients at st. john of god hospital, duayaw nkwanta, Ghana: a cross-sectional study

Background

Uropathogens are microorganisms that cause urinary tract infections (UTIs). Owing to higher blood glucose levels and compromised immune functions, treatment of uropathogens in diabetic patients is a challenge.

Aim

This study aims to assess the prevalence of uropathogens and their antibiotic susceptibility among diabetic patients at St. John of God Hospital at Duayaw Nkwanta (SJGHDN) in the Ahafo region of Ghana.

Methods

The cross-sectional study recruited 175 diabetic patients at SJGHDN between August and September 2023. Questionnaires were used to collect patients' background information. Fasting Blood Sugar (FBS) was assessed by using a glucometer. Urine samples were examined for the presence of uropathogens. A sterile inoculating loop with a calibrated volume of 2 µl was used for plating. Each colony equals 500 CFU/mL. Significant uropathogen was determined by multiplying the counted colonies by 500 to obtain CFU/mL. Positive uropathogen was defined as CFU ≥ 105/mL. Significant uropathogen was defined as ≥200 colonies per sample. The disc diffusion method was used to determine antibiotic susceptibility.

Results

Out of the 175 patients, 19.4% expressed various uropathogens with Escherichia coli being the predominant. Suboptimal glucose level was the most significant risk factor (p = 0.038). Glucosuria (p = 0.036), hazy urine (p = 0.028), positive leukocyte esterase (p = 0.001), and pus cells in urine sediment (p = 0.020) were significant indicators of uropathogen occurrence. Klebsiella pneumonia and Proteus mirabilis were resistant to ≥4 antibiotics. Amikacin, nitrofurantoin, levofloxacin, ciprofloxacin, and ceftriaxone demonstrated efficacy against the isolates.

Conclusion

This study underscores the notable prevalence of uropathogens in diabetic patients and the alarming levels of antibiotic resistance observed. The results highlight the critical need for vigilant monitoring and customized treatment approaches, particularly for diabetic patients exhibiting risk factors such as elevated urine glucose levels, cloudy urine, and presence of leukocyte esterase and pus cells in urine sediment. The significant resistance to frequently used antibiotics like co-trimoxazole and tetracycline points to the necessity of routine susceptibility testing and the use of alternative antibiotics for effective treatment. These findings can assist healthcare providers in more effectively managing and preventing UTIs in diabetic populations.

Materials-based incidence of urinary catheter associated urinary tract infections and the causative micro-organisms: systematic review and meta-analysis

BACKGROUND

Both long (> 30 days) and short-term (≤ 30 days) catheterisation has been associated with urinary tract infections (UTIs) due to the invasive nature of device insertion through the urethra. Catheter associated Urinary Tract Infections (CAUTIs) are common (prevalence of ~ 8.5%) infections which can be treated with antibiotics; however, CAUTIs are both expensive to treat and contributes to the antibiotic usage crisis. As catheters are unlikely be replaced for the management of patients' urination, ways of reducing CAUTIs are sought out, using the catheter device itself. The aim of this review is to assess the incidence of CAUTI and the causative micro-organisms when different urinary catheter devices have been used by humans, as reported in published research articles.

METHODS

A Systematic Literature Review was conducted in Ovid Medline, Web of Science and PubMed, to identify studies which investigated the incidence of UTI and the causative micro-organisms, in patients with different urinary catheter devices. The articles were selected based on a strict set of inclusion and exclusion criteria. The data regarding UTI incidence was extracted and calculated odds ratio were compared across studies and pooled when types of catheters were compared. CAUTI causative micro-organisms, if stated within the research pieces, were also gathered.

RESULTS

A total of 890 articles were identified, but only 26 unique articles met the inclusion/exclusion criteria for this review. Amongst the large cohort there were catheters of materials silicone, latex and PVC and catheter modifications of silver nanoparticles and nitrofurantoin antibiotics. The meta-analysis did not provide a clear choice towards a single catheter against another although silver-based catheters, and silver alloy, appeared to statistically reduce the OR of developing CAUTIs. At genus level the three commonest bacteria identified across the cohort were E. coli, Enterococcus spp. and Pseudomonas spp. whilst considering only at the genus level, with E. coli, Klebsiella pneumonia and Enterococcus faecalis most common at the species-specific level.

CONCLUSIONS

There does not appear to be a catheter type, which can significantly reduce the incidence of CAUTI's in patients requiring catheterisation. Ultimately, this warrants further research to identify and develop a catheter device material that will reduce the incidence for CAUTIs.

Unraveling the association of bacteria and urinary stones in patients with urolithiasis: an update review article

Urinary stone disease (USD) is a prevalent urological condition, ranking as one of the most common urinary tract disorders globally. Various risk factors influence the formation of kidney stones, and recent research indicates a rising prevalence of urolithiasis worldwide, particularly in developing countries. While the morbidity associated with urinary stones has decreased in recent years, long-term complications such as stone recurrence, kidney failure, and uremia continue to burden patients. Understanding the etiologies of urolithiasis, including the role of bacteria, is crucial as they can contribute to stone recurrence. The incidence of urinary tract infection (UTI) stones can be attributed to specific infectious risk factors, socio-demographic factors, and comorbid metabolic disorders. This review article explores the emerging evidence suggesting the involvement of bacteria in USD. It discusses the potential role of microorganisms in non-infection stones and highlights the association between UTIs and urolithiasis. Furthermore, it surveys the relationship between kidney stones and recurrent UTIs and the formation of bacterial biofilms in UTIs. Considering various risk factors, including biochemical stone analysis and the presence of bacteria, is essential for treating patients with infectious stones optimally. This review aims to provide an updated understanding of the association between bacteria and urinary stones in patients with urolithiasis, shedding light on the pathophysiology of urinary stone formation, urinary stone characteristics, and the urinary microbiome in urinary stones.

YELLOW RoUTIne prospective cohort study protocol: insight in the dynamics of bacteria in the elderly bladder

BACKGROUND

Asymptomatic bacteriuria (ASB) - the presence of bacteria in urine without urinary tract infection (UTI) related signs & symptoms (S&S) - is common in the elderly bladder and is not considered pathogenic for UTI. We hypothesise that colonisation with non-uropathogenic bacteria could protect the bladder from invasion of more harmful bacteria. The exact role and dynamics of bacteriuria in the relation to the development of a UTI is still unknown. We aim to provide insight into the course of bacteriuria in the elderly bladder and its relation to UTI in frail older adults.

METHODS AND ANALYSIS

A prospective observational cohort study is being conducted in Dutch nursing homes (NHs) between February 2024 and December 2025. Urine samples and case report forms (CRF) on UTI-related S&S will be collected from each consenting NH resident every 3 months for a follow-up period of 18 months. Whenever a UTI-suspicion occurs in between the 3 monthly time points, additional data and a urine sample will be collected. Urine samples undergo several urinalyses (e.g. dipstick and bacterial culture). Additional molecular analysis will be conducted on a selection of cultured Escherichia coli (E. coli) for virulence genes. Primary analyses will be conducted between residents with and without ASB at each time point. The primary outcome is UTI incidence during follow-up. In secondary analyses we will also take into account the low versus high presence of virulence genes of the E. coli.

DISCUSSION

The combination of high ASB prevalence and a reduced ability of frail older adults to express UTI-related S&S may lead to UTI misdiagnosis and inappropriate antibiotic use. To our knowledge, this is the first study to investigate the dynamics and role of bacteriuria in the elderly bladder and their potential protective effect on the development of UTI. The study findings with comprehensive analysis of epidemiological, clinical and molecular data could set the fundamental base for future guidelines and studies, and contribute to improving prevention, diagnosis and treatment of UTI in frail older adults, in addition to contributing to antibiotic stewardship in NHs.

Effects of dietary restriction and one-carbon metabolite supplementation during the first 63 days of gestation on the maternal gut, vaginal, and blood microbiota in cattle

BACKGROUND

Maternal diet quality and quantity have significant impacts on both maternal and fetal health and development. The composition and function of the maternal gut microbiome is also significantly influenced by diet; however, little is known about the impact of gestational nutrient restriction on the bovine maternal microbiome during early gestation, which is a critical stage for maternal microbiome-mediated fetal programming to take place. The objective of the present study was to evaluate the impacts of diet restriction and one-carbon metabolite (OCM) supplementation during early gestation on maternal ruminal, vaginal, and blood microbiota in cattle. Thirty-three beef heifers (approx. 14 months old) were used in a 2 × 2 factorial experiment with main factors of target gain (control [CON]; targeted 0.45 kg/d gain vs restricted [RES]; targeted - 0.23 kg/d gain), and OCM supplementation (+ OCM vs - OCM; n = 8/treatment; except n = 9 for RES-OCM). Heifers were individually fed, starting treatment at breeding (d 0) and concluding at d 63 of gestation. Ruminal fluid and vaginal swabs were collected on d - 2, d 35, and d 63 (at necropsy) and whole blood was collected on d 63 (necropsy). Bacterial microbiota was assessed using 16S rRNA gene (V3-V4) sequencing.

RESULTS

Overall ruminal microbiota structure was affected by gain, OCM, time, and their interactions. The RES heifers had greater microbial richness (observed ASVs) but neither Shannon nor Inverse Simpson diversity was significantly influenced by gain or OCM supplementation; however, on d 63, 34 bacterial genera showed differential abundance in the ruminal fluid, with 25 genera enriched in RES heifers as compared to CON heifers. In addition, the overall interaction network structure of the ruminal microbiota changed due to diet restriction. The vaginal microbiota community structure was influenced by gain and time. Overall microbial richness and diversity of the vaginal microbiota steadily increased as pregnancy progressed. The vaginal ecological network structure was distinctive between RES and CON heifers with genera-genera interactions being intensified in RES heifers. A relatively diverse bacterial community was detected in blood samples, and the composition of the blood microbiota differed from that of ruminal and vaginal microbiota.

CONCLUSION

Restricted dietary intake during early gestation induced significant alterations in the ruminal microbiota which also extended to the vaginal microbiota. The composition of these two microbial communities was largely unaffected by OCM supplementation. Blood associated microbiota was largely distinctive from the ruminal and vaginal microbiota.

Nanoplasmonic Rapid Antimicrobial-Resistance Point-of-Care Identification Device: RAPIDx

The emergence of antibiotic resistance has become a global health crisis, and everyone must arm themselves with wisdom to effectively combat the "silent tsunami" of infections that are no longer treatable with antibiotics. However, the overuse or inappropriate use of unnecessary antibiotics is still routine for administering them due to the unavailability of rapid, precise, and point-of-care assays. Here, a rapid antimicrobial-resistance point-of-care identification device (RAPIDx) is reported for the accurate and simultaneous identification of bacterial species (genotype) and target enzyme activity (phenotype). First, a contamination-free active target enzyme is extracted via the photothermal lysis of preconcentrated bacteria cells on a nanoplasmonic functional layer on-chip. Second, the rapid, precise identification of pathogens is achieved by the photonic rolling circle amplification of DNA on a chip. Third, the simultaneous identification of bacterial species (genotype) and target enzyme activity (phenotype) is demonstrated within a sample-to-answer 45 min operation via the RAPIDx. It is believed that the RAPIDx will be a valuable method for solving the bottleneck of employing on-chip nanotechnology for antibiotic-resistant bioassay and other infectious diseases.

Transposon mutagenesis screen in Klebsiella pneumoniae identifies genetic determinants required for growth in human urine and serum

Klebsiella pneumoniae is a global public health concern due to the rising myriad of hypervirulent and multidrug-resistant clones both alarmingly associated with high mortality. The molecular mechanisms underpinning these recalcitrant K. pneumoniae infection, and how virulence is coupled with the emergence of lineages resistant to nearly all present-day clinically important antimicrobials, are unclear. In this study, we performed a genome-wide screen in K. pneumoniae ECL8, a member of the endemic K2-ST375 pathotype most often reported in Asia, to define genes essential for growth in a nutrient-rich laboratory medium (Luria-Bertani [LB] medium), human urine, and serum. Through transposon directed insertion-site sequencing (TraDIS), a total of 427 genes were identified as essential for growth on LB agar, whereas transposon insertions in 11 and 144 genes decreased fitness for growth in either urine or serum, respectively. These studies not only provide further knowledge on the genetics of this pathogen but also provide a strong impetus for discovering new antimicrobial targets to improve current therapeutic options for K. pneumoniae infections.

Novel Nano Drug-Loaded Hydrogel Coatings for the Prevention and Treatment of CAUTI

Catheter-associated urinary tract infection (CAUTI) is a prevalent type of hospital-acquired infection, affecting approximately 15% to 25% of patients with urinary catheters. Long-term use of the catheter can lead to colonization of microorganisms and biofilm formation, and may develop into bacterial CAUTI. However, the frequent replacement of catheters in clinical settings can result in tissue damage, inflammation, ulceration, and additional complications, causing discomfort and pain for patients. In light of these challenges, a novel nanodrug-supported hydrogel coating called NP-AM/FK@OMV-P/H has been developed in this study. Through in vitro experiments, it is confirmed that OMV nano-loaded liquid gel coating has an effective reaction against E.coli HAase and releases antibacterial drugs. This coating has also demonstrated strong inhibition of E.coli and has shown the ability to inhibit the formation of bacterial biofilm. These findings highlight the potential of the OMV nanoparticle gel coating in preventing and treating bacterial infections. Notably, NP-AM/FK@OMV-P/H has exhibited greater efficacy against multidrug-resistant E.coli associated with UTIs compared to coatings containing single antimicrobial peptides or antibiotics. Additionally, it has demonstrated good biosecurity. In conclusion, the NP-AM/FK@OMV-P/H coating holds great potential in providing benefits to patients with CAUTI.