Search Results (122)

Background: Urosepsis is a life-threatening condition accounting for approximately 20–30% of all sepsis cases and typically arises from ascending infection by uropathogenic Escherichia coli (UPEC). Disease progression is mediated by virulence factors, including adhesins, iron acquisition systems, and toxins. Among these, P fimbriae, particularly papGII adhesin subunit, have been implicated in the transition from uncomplicated urinary tract infection (UTI) to severe urosepsis. This study aimed to evaluate whether papGII carriage, alone or in combination with other UPEC virulence determinants and clinical risk factors, can predict urosepsis. Methods: A total of 60 paired Escherichia coli isolates from concurrent blood and urine samples of adults with clinical sepsis were collected between January and June 2024. Control isolates were obtained from patients with cystitis (n = 28) and pyelonephritis (n = 32). Polymerase chain reaction (PCR) assays were used to detect fifteen virulence-associated genes, including the pap operon (with papG allelic variants), the type 1 fimbriae (fimH), S fimbriae (sfaS), curli fimbriae (csgA), afa/Dr adhesin operon genes, cytotoxic necrotizing factor 1 (cnf1), and the aerobactin biosynthesis (iucD) and receptor (iutA) genes. Associations between gene carriage and clinical groups were analyzed using chi-square tests. Results: The incidence of urosepsis increased with age, peaking in the 60–69-year age group. Renal disease and catheterization were identified as significant risk factors (p < 0.05). More than 95% of UPEC isolates carried the csgA gene associated with biofilm formation and the iucD gene. The α- hemolysin toxin (hlyA) was significantly associated with urosepsis [X²(1, N = 120) = 6.62, p = 0.03]. No significant differences were observed in the carriage of papA, papC, or fimH. Although papGII was present in 65% of urosepsis-associated UPEC isolates, it did not demonstrate a statistically significant independent association with urosepsis [p = 0.1]. Conclusion: This study demonstrates that while papGII may contribute to the pathogenic potential of UPEC and facilitate systemic infection, it is not a reliable independent predictor of urosepsis. Full article

Urinary tract infections (UTIs), predominantly caused by Escherichia coli, constitute a major global health issue due to the escalating antimicrobial resistance. This study was designed to assess the in vitro susceptibility of fosfomycin among clinical uropathogenic Escherichia coli (UPEC) isolates and to detect plasmid-mediated fosA3 and fosC2 genes in those exhibiting fosfomycin resistance. A total of 158 non-duplicated UPEC strains were collected from urine samples of patients with UTIs. Antimicrobial susceptibility of these isolates was evaluated. Phenotypic detection of extended-spectrum β-lactamases (ESBL) and carbapenemase producers in UPEC was assessed. Identification of plasmid mediated fosA3 and fosC2 genes in those exhibiting fosfomycin resistance was carried out by PCR. A total of 72% of the isolates demonstrated multidrug resistance (MDR). Extensively drug-resistant (XDR) isolates represented 15%, while PDR isolates were rare (0.6%, 1/158). ESBLs were detected in 40% of the isolates, and 31% exhibited carbapenemase production. Fosfomycin resistance was detected in 9.5% of UPEC isolates, with the fosA3 gene identified in 33% of these resistant strains, whereas fosC2 gene was not identified in any isolate. Fosfomycin demonstrated considerable in vitro activity against carbapenemase-producing, ESBL-producing, and MDR isolates with susceptibility rates of 78%, 84%, and 97%, respectively. Fosfomycin resistance among UPEC isolates is emerging but still at a relatively low level of resistance. Continuous surveillance and antimicrobial stewardship are essential to preserve fosfomycin efficacy. Full article

Uropathogenic Escherichia coli (UPEC) is a leading cause of urinary tract infections (UTIs) in companion animals. This study characterized 42 UPEC isolates recovered from dogs and cats at the University of Florida, College of Veterinary Medicine Diagnostic Laboratories between 2023 and 2024, focusing on antimicrobial resistance (AMR), virulence gene profiles, biofilm-forming ability, and phylogroup distribution of the isolates. Antimicrobial susceptibility testing (AST) showed that 40.48% of the isolates were resistant to at least one of the tested antibiotics, and 9.52% exhibited multidrug resistance (MDR). Phylogroup B2 was predominant (69.05%), and 61.90% of isolates demonstrated strong biofilm formation in artificial human urine. Virulence gene analysis revealed the presence of genes mediating adhesion (fim, pap, sfa), iron acquisition (fyuA, iro), biofilm formation (csg, bcs, pga, ycg/ymg), motility (fli, mot, flh), and stress response (oxyR, soxR/S, kat). Multiple plasmids carrying AMR and virulence determinants were also identified. The co-occurrence of the traits underscores the potential for persistent and recurrent infections, which can complicate therapeutic outcomes and facilitate horizontal gene transfer (HGT). The detection of antimicrobial-resistant, highly virulent UPEC strains possessing human UPEC traits in companion animals suggests the risk of zoonotic and reverse-zoonotic transmission, particularly in households with close pet–owner interactions. These findings emphasize the importance of judicious antimicrobial use, routine molecular surveillance, and integrated One Health strategies to mitigate the veterinary and public health threats associated with UPEC infections in companion animals. Full article

Background: Uropathogenic Escherichia coli (UPEC) is the primary etiological agent of urinary tract infections (UTIs) worldwide. The emergence of strains combining high virulence with multidrug resistance (MDR) poses a significant challenge to public health. This study aimed to characterize the phylogenetic distribution, virulence profiles, and antimicrobial susceptibility of UPEC isolates recovered from patients in the metropolitan area of Buenos Aires (AMBA), Argentina. Methodology: Phylogenetic groups, the ST131 lineage, and virulence-associated genes were identified using PCR-based assays. Antimicrobial susceptibility testing (AST) was performed using automated methods and extended-spectrum beta-lactamase (ESBL) production was confirmed using the double-disk synergy test. Colistin (COL) resistance was evaluated by Colistin Drop Test and PCR screening for the mcr-1 (mobile colistin resistance gene 1). Biofilm formation was detected by the Tissue Culture Plate (TCP) method, whereas phenotypic virulence factors (VF) were assessed with Congo Red agar, hemagglutination, and hemolysis assays. Results: Phylogenetic groups B2 (43.8%) and D (26.7%), typically associated with extraintestinal infections, were the most frequent. The high-risk clone B2-ST131 was detected in 6.7% of isolates. Biofilm production was observed in 92.4% of the isolates, with curli fimbriae (87.6%) being the most frequently expressed VF. The highest resistance rates were observed for ampicillin (62.1%), ampicillin-sulbactam (39.8%), and trimethoprim-sulfamethoxazole (25.2%). Interestingly, 3.8% of isolates exhibited colistin resistance, despite the absence of the mcr-1 gene. Conclusions: This study highlights the detection of MDR-UPEC isolates that showed strong resistance to fluoroquinolones and were ESBL producers with high virulence in Argentina, justifying future research encompassing genomic and epidemiological monitoring of local UPEC, which is essential for managing infections and developing new therapeutic and preventive measures. Full article

Uropathogenic Escherichia coli (UPEC) that form biofilms exhibit high-level antibiotic resistance, which poses substantial challenges to current therapeutic strategies for urinary tract infection (UTI). There is an urgent need for strategies specifically targeting UPEC biofilms. This study investigated the effects of the n-butanol extract of Polygonum capitatum (BPC) on UPEC strains, focusing on its antibacterial activity, biofilm formation, bacterial motility, adhesion capacity, and cell membrane integrity. The disk diffusion method, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays demonstrated that BPC exhibited potent antibacterial activity against both reference and clinically isolated UPEC strains. Time–kill curve assays further confirmed that BPC inhibits bacterial growth in a time-dependent manner. BPC inhibited UPEC biofilm formation in a dose-dependent manner, significantly reducing biofilm formation in both reference and clinical UPEC strains. Furthermore, BPC disrupted cell membrane integrity in UPEC strain CFT073, resulting in the leakage of alkaline phosphatase (AKP), β-galactosidase, and intracellular proteins. BPC treatment also significantly reduced bacterial surface hydrophobicity, impaired swimming and swarming motility, and diminished adhesion and invasion capabilities. A total of 32 active compounds, predominantly flavonoids, were identified in BPC by UHPLC-Q-orbitrap MS/MS. Molecular docking studies revealed that several compounds in BPC, such as quercetin-3,4′-O-di-beta-glucoside, exhibited strong binding affinity to AKP and β-galactosidase, further supporting its potential to disrupt membrane integrity and inhibit biofilm formation. Thus, BPC exerts anti-UPEC effects through biofilm disruption and multi-targeted anti-virulence mechanisms, highlighting its potential as a novel therapeutic or adjunctive agent for UTI, particularly against recalcitrant biofilm-associated infections. The mode of action of BPC provides a scientific basis for developing new anti-infective strategies as alternatives to conventional antibiotics. Full article

Quorum-sensing (QS) systems play a crucial role in regulating virulence, biofilm formation, and antibiotic resistance in clinically relevant microbes. This review explores the potential of QS systems as targets for developing novel plant-based therapeutic strategies using bioinformatics, aimed at combating highly pathogenic bacteria: uropathogenic Escherichia coli (UPEC) and Pseudomonas aeruginosa. We examine the key components and molecular pathways of QS systems in these microbes, including autoinducer synthases, receptors, and regulatory proteins. In UPEC, we discuss the LuxS-dependent autoinducer (AI)-2 system, while for P. aeruginosa, we analyze the more complex interconnected Las, Rhl, and PQS circuits. We highlight how these systems control the expression of virulence factors and contribute to biofilm formation, emphasizing their importance in pathogenesis. Furthermore, we explore bioinformatics approaches for identifying and characterizing QS components, i.e., by predicting protein structures and interactions. The potential of in silico screening for QS inhibitors is also discussed, along with challenges and opportunities in targeting QS systems for therapeutic interventions. By integrating microbiological, molecular, and computational perspectives, this review aims to provide insights into the application of bioinformatics in understanding and targeting QS systems in these clinically significant pathogens. The goal is to facilitate the development of novel anti-virulence approaches in search of novel antibiotics that could complement or replace traditional antibiotic treatments, addressing the growing concern of antimicrobial resistance in these clinically relevant microbes. Full article

Background/Objectives: Bacterial outer membrane vesicles (OMVs) play a role in bacterial communication, virulence, antimicrobial resistance, and host–pathogen interaction. OMV isolation is a key step for studying these particles’ functions; nevertheless, isolation procedures can greatly influence the yield, purity, and structural integrity of OMVs, thereby affecting downstream biological analyses and functional interpretation. Methods: In this study, we compared the efficacy of two OMV isolation techniques, differential ultracentrifugation (dUC) and size-exclusion chromatography (SEC), in separating and concentrating vesicles produced by two Escherichia coli strains belonging to uropathogenic (UPEC) and Shiga toxin-producing (STEC) pathotypes. The isolated OMVs were characterized using a multi-analytical approach including transmission and scanning electron microscopy (TEM, SEM), nanoparticle tracking analysis (NTA), dynamic light scattering (DLS), ζ-potential measurement, and protein quantification to assess the purity of the preparations. Results: Samples obtained by dUC exhibited higher total protein content, broader particle size distributions, and more pronounced contamination by non-vesicular material. In contrast, SEC yielded morphologically homogeneous and structurally well-preserved vesicles, higher particle-to-protein ratios, and lower total protein content, reflecting reduced co-isolation of protein aggregates. NTA and DLS analyses revealed polydisperse populations in samples obtained with both isolation methods, with DLS measurements highlighting the contribution of larger or transient aggregates. ζ-potential values were close to neutrality for all samples, consistent with limited electrostatic repulsion and with the aggregation tendencies observed in some preparations. Conclusions: This study describes features of OMV produced by two relevant E. coli strains considering two isolation strategies which exert method- and strain-dependent effects on vesicle properties, including size distribution and surface charge, and emphasizes the trade-offs between yield, purity, and vesicle integrity. Full article

More than 90% of bladder cancers are classified as urothelial carcinomas (UC), with approximately 75% of these cases presenting as non-muscle-invasive bladder cancer (NMIBC). Bacillus Calmette–Guérin (BCG) is the current standard immunotherapy for NMIBC, yet it suffers from limited efficacy, frequent tumor recurrence, and substantial toxicity. These limitations underscore the need for safer, more effective, and accessible alternatives. We investigated whether uropathogenic Escherichia coli (UPEC), a natural inducer of immune responses in the bladder, could serve as a novel intravesical immunotherapeutic agent. Using orthotopic bladder cancer models in both mice (MB49-luc) and rats (AY-27), we evaluated the efficacy, specificity, immune dependence, and safety of formaldehyde-inactivated UPEC strains, including mutants with altered type 1 fimbriae expression. Intravesical administration of inactivated UPEC significantly reduced tumor burden and prolonged survival, outperforming BCG in murine models and demonstrating equivalent efficacy with markedly reduced toxicity in rats. The antitumor effect was T cell-dependent and partially mediated by type I fimbriae, which facilitated tumor-specific adhesion. Notably, systemic (subcutaneous) administration of UPEC abrogated efficacy and increased mortality, emphasizing the necessity of localized bladder delivery. In conclusion, we identify inactivated UPEC as a potent, tumor-targeting, and T cell-dependent immunotherapeutic agent with a superior safety profile compared to BCG. This approach might represent a promising and practical alternative for bladder cancer treatment. Full article

Background: Urinary tract infections (UTIs) rank among the most prevalent infectious diseases globally, with recurrent UTIs (rUTIs) posing substantial therapeutic challenges due to the lack of durable protective immunity. While trained immunity augments innate immune responses, its induction and functional significance in bladder-resident group 3 innate lymphoid cells (ILC3s) remain unknown. This study investigates whether ILC3s develop trained immunity following uropathogenic Escherichia coli (UPEC) exposure and how they contribute to mucosal defense against rUTIs. Methods: The ILC3 counts were detected in bladder sections from UTI patients and health controls (HC). A recurrent UTI mouse model was established through primary and secondary urethral UPEC inoculation. Bacterial loads in tissues were assessed, and single-cell suspensions were analyzed via flow cytometry. Bladder naïve- and UPEC-trained ILC3s were adoptively transferred, with evaluations of histopathology, epithelial barrier function, inflammation, and antimicrobial peptides. The in vitro ILC3 cell line MNK-3 was detected for IL-17A and IL-22 production following primary and secondary UPEC lysate stimulation. Results: We demonstrate that primary UPEC infection triggers ILC3 expansion in both human and murine bladders. Upon secondary challenge, these ILC3s develop trained immunity, characterized by enhanced proliferation, amplified IL-17A and IL-22 production, and improved pathogen clearance. Mechanistically, trained ILC3s reinforce urothelial barrier integrity through upregulation of antimicrobial peptides (Reg3b/Reg3g) and attenuate inflammatory pathology by suppressing pro-inflammatory cytokines (IL-6, TNF-α). Conclusions: We uncover an endogenous defense mechanism wherein UPEC primes bladder ILC3s via trained immunity, enabling amplified IL-17A- and IL-22-mediated protection against recurrent infections. These findings establish ILC3-trained immunity as a novel conceptual foundation, providing a basis for developing immunotherapies against rUTIs. Full article

Urinary tract infections (UTIs) are common in children and are predominantly caused by uropathogenic Escherichia coli (UPEC). An increasing proportion of these strains produce extended-spectrum β-lactamases (ESBLs), which render β-lactam antibiotics ineffective. Interestingly, some patients with ESBL-producing UTIs improve clinically following treatment with antibiotics like cephalexin, despite demonstrated in vitro resistance. Working alongside and at times synergistically with antibiotics, host immune factors, such as the antimicrobial peptide cathelicidin (LL-37), contribute to bacterial clearance through direct killing and inhibition of biofilm formation. In this review, we summarize the current understanding of pediatric ESBL-producing UPEC infections and present selected in vitro and in vivo experimental data evaluating the combined effects of LL-37 and cephalexin on clinical isolates. Although no synergy was observed, ESBL-producing isolates demonstrated reduced bacterial burden in vivo compared to a non-ESBL UPEC strain. These findings suggest that host immune factors and environmental conditions may influence the fitness and virulence of drug-resistant UTI pathogens, warranting further investigation. Full article

Type I-E and I-F CRISPR-Cas systems were identified in 237 E. coli strains isolated from patients with urinary tract infections (UTIs) between 2004 and 2019. The strains were classified into nine distinct groups (I–IX) based on the presence or absence of cas genes and repeat regions (RRs). Within the type I-E systems, two sequence variants were identified, distinguished by polymorphisms in the casB, cas3, cas7, cas5, and cas6 genes. The direct repeats (DRs) also differed, with I-E-associated RRs ranging from 26 to 32 bp and I-F-associated RRs consistently being 28 bp. We identified 762 unique spacers (29–35 bp in length) across the strain collection, while the number of spacers per strain varied from 1 to 47, and potential DNA targets were determined for 65 spacers, targeting 38 bacteriophage genomes, 19 plasmids, and 8 cas genes of the I-F type CRISPR-Cas system. Multilocus sequence typing (MLST) revealed 68 sequence types and 24 clonal complexes (CCs), with the most prevalent being ST131, CC10, CC69, CC405, CC14, CC38, CC73, and CC648. Significant correlations were observed between specific phylogroups/CCs, the type of CRISPR-Cas system present, and distinct profiles of virulence and antibiotic resistance genes. Full article

Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs) and a major contributor to the global antimicrobial resistance crisis. The increasing prevalence of multidrug-resistant (MDR) strains, including expanded-spectrum β-lactamases (ESBL) and carbapenemase-producing isolates, severely limits treatment options. This review provides an overview on the key molecular mechanisms of UPEC antibiotic resistance, such as enzymatic inactivation, target-site mutations, efflux pump activity, and biofilm formation. Beyond conventional antibiotics, special emphasis is placed on phytochemical strategies as promising alternatives. Flavonoids, alkaloids, terpenoids, and essential oils exhibit antibacterial, anti-adhesive, and antibiofilm properties. These natural bioactive compounds modulate motility, suppress fimbrial expression, inhibit quorum sensing, and enhance antibiotic efficacy, acting both as standalone agents and as adjuvants. Current in vitro and in vivo studies highlight the potential of plant-derived compounds and biologically based therapies to combat UPEC. However, challenges related to standardization, bioavailability, and clinical validation remain unresolved. Integrating molecular mechanistic insights with advanced phytochemical research may offers a sustainable and effective strategy for mitigating UPEC antibiotic resistance. Full article

Background: Escherichia coli strains associated with poultry are increasingly recognized as reservoirs of both virulence and resistance genes, posing significant zoonotic risks throughout the food production chain. However, the genotypic architecture and pathogenic potential of isolates from large-scale turkey farms remain under characterized, particularly in the context of extended-spectrum β-lactamase (ESBL) production. Methods: A total of 160 ESBL-producing E. coli isolates were collected from healthy turkeys on intensive Hungarian farms. Whole genome sequencing (WGS) was performed to characterize virulence factors. Functional annotation included screening for fimbrial adhesins, iron acquisition systems, secretion pathways, and autotransporter toxins, using VirulenceFinder and Prodigal-based genome annotations. Data analysis included assembly quality control with QUAST and BUSCO, and comprehensive virulome profiling. Results: The isolates exhibited a functionally diverse virulence profile encompassing classical ExPEC-associated colonization factors (type I, P, S fimbriae; curli; ECP), multiple iron acquisition systems (enterobactin, salmochelin, aerobactin, yersiniabactin, and heme uptake), and key secretion systems (LEE-associated T3SS and T2SS). Genetic hallmarks of avian pathogenic E. coli (APEC), uropathogenic pathogenic E. coli (UPEC), and enteropathogenic E. coli (EPEC) pathotypes co-occurred in 44% of the isolates, indicating a mosaic virulence landscape. Notably, serine protease autotransporters of Enterobacteriaceae (SPATE) toxins (Vat, Pic) and ColV-type plasmid-associated modules were frequently detected. All isolates were confirmed by ESBL producers, highlighting their antimicrobial resistance potential. Conclusions: This study reveals that E. coli strains isolated from turkeys possess a complex, host-adapted virulence repertoire capable of supporting both enteric and extraintestinal infections. The co-occurence of APEC-, UPEC-, and EPEC-like traits—combined with ESBL production—underscores their One Health relevance. These findings support the need for host-specific surveillance, functional validation, and integrative control strategies in poultry systems. Full article

Urinary Tract Infection (UTI), the second most common infectious disease globally, poses a particularly significant threat to adult female populations. Epidemiological data show that Uropathogenic Escherichia coli (UPEC) is responsible for approximately 75% to 90% of UTI cases. Currently, antibiotic therapy constitutes the primary treatment for UTIs. However, the rising prevalence of antimicrobial resistance, particularly among Escherichia coli strains, is increasingly compromising treatment efficacy and elevating the risk of therapeutic failure and complications. Considering this serious challenge, the urgent exploration and development of alternative therapies for UTIs, particularly vaccine therapies, to supplement or replace antibiotic use is crucial. Polysaccharide conjugate vaccines represent a highly successful strategy in bacterial vaccine development, playing a pivotal role in the prevention and control of human infectious diseases. This article aims to review the research progress on UTI vaccines and focus on the preparation methods of polysaccharide conjugate vaccines, encompassing traditional chemical conjugation techniques and emerging biosynthetic methods. Through an in-depth analysis of biosynthetic methods, this article identifies the key steps and proposes insights for further optimization strategies for polysaccharide conjugate vaccines. It is hoped that this study will provide a more comprehensive and in-depth reference for the development of UTI vaccines. Full article

Background: The increasing attention on extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli strains isolated from poultry flocks stems from concerns about their virulence potential and zoonotic risk. Of particular significance is the identification of extraintestinal pathogenic E. coli (ExPEC) pathotypes in poultry, as these strains pose not only animal health concerns but also serious threats to food safety and public health. Mapping the genetic background of pathogenicity and antimicrobial resistance is essential for risk assessment and the development of effective control strategies. Methods: A total of 87 E. coli isolates were isolated from tracheal and cloacal swab samples collected from healthy chickens between 2022 and 2023. Whole-genome sequencing was performed using Illumina and MGI next-generation sequencing platforms. Bioinformatic analyses were conducted to identify virulence-associated genes and pathotype markers using multiple reference databases, including VirulenceFinder. The frequency of virulence genes was summarized both in tabular form and visualized through graphical representations. Results: A substantial proportion of the isolates harbored virulence genes linked to various ExPEC pathotypes, particularly uropathogenic E. coli (UPEC), avian pathogenic E. coli (APEC), and neonatal meningitis-causing E. coli (NMEC). The most frequently detected colonization factors included members of the fim, pap, ecp, and fae gene families. Among fitness-related genes, iron acquisition systems—ent, chu, iro, iuc, fep, and ybt—were especially prevalent. Classic UPEC-associated genes such as pap and fimH, along with the APEC-related iutA and vat, were found at high frequencies. Four isolates exhibited a virulence gene profile characteristic of the NMEC pathotype (ibeA, kpsD/M/T, fimH). In contrast, hallmark genes of enteric pathotypes were absent from all isolates. Conclusions: The predominance of extraintestinal virulence factors in the examined poultry-derived E. coli strains underscores their zoonotic potential. The complete absence of enteric pathotype markers indicates that the studied poultry populations primarily harbor ExPEC-like strains. These findings highlight the critical need for ongoing genomic surveillance and targeted preventive strategies within poultry production systems. Full article