Characteristics of Escherichia coli causing persistence or relapse of urinary tract infections: phylogenetic groups, virulence factors and biofilm formation

Antimicrobial Resistance in Uropathogenic Escherichia coli Strains Isolated from Relapses from Recurrent Urinary Tract Infections

Little is known about the characteristics of uropathogenic Escherichia coli (UPEC) associated with recurrent urinary tract infections (RUTIs). The present study aimed to analyze the phenotypic antimicrobial resistance of recurrent UPEC isolates attributable to either relapse or reinfection. A total of 140 E. coli strains were isolated from 70 outpatients with RUTIs. All isolates were analyzed by random amplified polymorphic DNA-polymerase chain reaction to evaluate genetic similarity between the first and second isolates. We found that 64.2% (45/70) of outpatients had a relapse with the primary infecting E. coli strain and 35.7% (25/70) had reinfection with a new E. coli strain. Compared with reinfecting strains, relapse UPEC isolates exhibited much higher antimicrobial resistance; 89% of these isolates were multidrug-resistant and 46.6% were extended-spectrum β-lactamase producers. Our study provides evidence that RUTIs are mainly driven by the persistence of the original strain in the host (relapses) despite appropriate antibiotic treatments, and only RUTIs attributed to relapses seem to favor multidrug resistance in UPEC isolates.

Characterization of bacteriophages infecting multidrug-resistant uropathogenic Escherichia coli strains

Uropathogenic Escherichia coli (UPEC) is the most common causative agent of urinary tract infections, and strains that are resistant to antibiotics are a major problem in treating these infections. Phage therapy is a promising alternative approach that can be used to treat infections caused by polyresistant bacterial strains. In the present study, 16 bacteriophages isolated from sewage and surface water were investigated. Phage host specificity was tested on a collection of 77 UPEC strains. The phages infected 2-44 strains, and 80% of the strains were infected by at least one phage. The susceptible E. coli strains belonged predominantly to the B2 phylogenetic group, including strains of two clones, CC131 and CC73, that have a worldwide distribution. All of the phages belonged to class Caudoviricetes and were identified as members of the families Straboviridae, Autographiviridae, and Drexlerviridae and the genera Kagunavirus, Justusliebigvirus, and Murrayvirus. A phage cocktail composed of six phages - four members of the family Straboviridae and two members of the family Autographiviridae - was prepared, and its antibacterial activity was tested in liquid medium. Complete suppression of bacterial growth was observed after 5-22 hours of cultivation, followed by partial regrowth. At 24 hours postinfection, the cocktail suppressed bacterial growth to 43-92% of control values. Similar results were obtained when testing the activity of the phage cocktail in LB and in artificial urine medium. The results indicate that our phage cocktail has potential to inhibit bacterial growth during infection, and they will therefore be preserved in the national phage bank, serving as valuable resources for therapeutic applications.

The biological function of the type II toxin-antitoxin system ccdAB in recurrent urinary tract infections

Urinary tract infections (UTIs) represent a significant challenge in clinical practice, with recurrent forms (rUTIs) posing a continual threat to patient health. Escherichia coli (E. coli) is the primary culprit in a vast majority of UTIs, both community-acquired and hospital-acquired, underscoring its clinical importance. Among different mediators of pathogenesis, toxin-antitoxin (TA) systems are emerging as the most prominent. The type II TA system, prevalent in prokaryotes, emerges as a critical player in stress response, biofilm formation, and cell dormancy. ccdAB, the first identified type II TA module, is renowned for maintaining plasmid stability. This paper aims to unravel the physiological role of the ccdAB in rUTIs caused by E. coli, delving into bacterial characteristics crucial for understanding and managing this disease. We investigated UPEC-induced rUTIs, examining changes in type II TA distribution and number, phylogenetic distribution, and Multi-Locus Sequence Typing (MLST) using polymerase chain reaction (PCR). Furthermore, our findings revealed that the induction of ccdB expression in E. coli BL21 (DE3) inhibited bacterial growth, observed that the expression of both ccdAB and ccdB in E. coli BL21 (DE3) led to an increase in biofilm formation, and confirmed that ccdAB plays a role in the development of persistent bacteria in urinary tract infections. Our findings could pave the way for novel therapeutic approaches targeting these systems, potentially reducing the prevalence of rUTIs. Through this investigation, we hope to contribute significantly to the global effort to combat the persistent challenge of rUTIs.

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

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

ESBL-Producing and Non-ESBL-Producing Escherichia coli Isolates from Urinary Tract Differ in Clonal Distribution, Virulence Gene Content and Phylogenetic Group

Purpose

The objectives of this study are to determine the differences in clonality, virulence gene (VG) content and phylogenetic group between non extended-spectrum beta-lactamase-producing E. coli (non-ESBL-EC) and ESBL-EC isolates from urine.

Patients and Methods

This study characterized a total of 100 clinical E. coli isolates consecutively obtained from the inpatients hospitalized in The First Affiliated Hospital of Ningbo University in China by polymerase-chain reaction (PCR).

Results

Phylogenetic group B2 was found to be the most prevalent in both ESBL-EC and non-ESBL-EC group. Among 100 clinical isolates, the count of acquired virulence genes in group B2 was found to be significantly higher than that in group A, B1, and D (p <0.001). Additionally, the presence of content within virulence genes (the total number of virulence genes detected per isolate) in B2 of non-ESBL-EC and ESBL-EC showed a significant difference (p<0.001). ST131 was detected exclusively in ESBL-EC, while ST95 and ST73 were the main sequence types in non-ESBL-EC.

Conclusion

Our study demonstrated the different distribution of MLST, phylogenetic group in ESBL-EC and non-ESBL-EC group. The inverse association between beta-lactamase resistance and VG content performed in this study should get a lot more attention. At the same time, we should also be wary of the appearance of non-ESBL-EC isolates of group B2 harboring more virulence genes which will lead to high pathogenicity.

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

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

Comparative Genomic Analysis of ST131 Subclade C2 of ESBL-Producing E. coli Isolates from Patients with Recurrent and Sporadic Urinary Tract Infections

The global emergence of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-E. coli), mainly causing urinary tract infections (UTI), is a major threat to human health. ESBL-E. coli sequence type (ST) 131 is the dominating clone worldwide, especially its subclade C2. Patients developing recurrent UTI (RUTI) due to ST131 subclade C2 appear to have an increased risk of recurrent infections. We have thus compared the whole genome of ST131 subclade C2 isolates from 14 patients with RUTI to those from 14 patients with sporadic UTI (SUTI). We aimed to elucidate if isolates causing RUTI can be associated with specific genomic features. Paired isolates from patients with RUTI were identical, presenting 2-18 single nucleotide polymorphism (SNP) differences for all six patients investigated. Comparative genomic analyses, including virulence factors, antibiotic resistance, pangenome and SNP analyses did not find any pattern associated with isolates causing RUTI. Despite extensive whole genome analyses, an increased risk of recurrences seen in patients with UTI due to ST131 subclade C2 isolates could not be explained by bacterial genetic differences in the two groups of isolates. Hence, additional factors that could aid in identifying bacterial properties contributing to the increased risk of RUTI due to ESBL-E. coli ST131 subclade C2 remains to be explored.

Characterization of host and escherichia coli strains causing recurrent urinary tract infections based on molecular typing

BACKGROUND

Escherichia coli is the leading pathogen responsible for urinary tract infection (UTI) and recurrent UTI (RUTI). Few studies have dealt with the characterization of host and bacteria in RUTI caused by E. coli with genetically identical or different strains. This study aimed to investigate the host and bacterial characteristics of E. coli RUTI based on molecular typing.

RESULTS

Patients aged 20 years or above who presented with symptoms of UTI in emergency department or outpatient clinics between August 2009 and December 2010 were enrolled. RUTI was defined as patients had 2 or more infections in 6 months or 3 or more in 12 months during the study period. Host factors (including age, gender, anatomical/functional defect, and immune dysfunction) and bacterial factors (including phylogenicity, virulence genes, and antimicrobial resistance) were included for analysis. There were 41 patients (41%) with 91 episodes of E. coli RUTI with highly related PFGE (HRPFGE) pattern (pattern similarity > 85%) and 58 (59%) patients with 137 episodes of E. coli RUTI with different molecular typing (DMT) pattern, respectively. There was a higher prevalence of phylogenetic group B2 and neuA and usp genes in HRPFGE group if the first episode of RUTI caused by HRPFGE E. coli strains and all episodes of RUTI caused by DMT E. coli strains were included for comparison. The uropathogenic E. coli (UPEC) strains in RUTI were more virulent in female gender, age < 20 years, neither anatomical/ functional defect nor immune dysfunction, and phylogenetic group B2. There were correlations among prior antibiotic therapy within 3 months and subsequent antimicrobial resistance in HRPFGE E. coli RUTI. The use of fluoroquinolones was more likely associated with subsequent antimicrobial resistance in most types of antibiotics.

CONCLUSIONS

This study demonstrated that the uropathogens in RUTI were more virulent in genetically highly-related E. coli strains. Higher bacterial virulence in young age group (< 20 years) and patients with neither anatomical/functional defect nor immune dysfunction suggests that virulent UPEC strains are needed for the development of RUTI in healthy populations. Prior antibiotic therapy, especially the fluoroquinolones, within 3 months could induce subsequent antimicrobial resistance in genetically highly-related E. coli RUTI.

Characterization of cephalosporin and fluoroquinolone resistant Enterobacterales from Irish farm waste by whole genome sequencing

Background

The Enterobacterales are a group of Gram-negative bacteria frequently exhibiting extended antimicrobial resistance (AMR) and involved in the transmission of resistance genes to other bacterial species present in the same environment. Due to their impact on human health and the paucity of new antibiotics, the World Health Organization (WHO) categorized carbapenem resistant and ESBL-producing as critical. Enterobacterales are ubiquitous and the role of the environment in the transmission of AMR organisms or antimicrobial resistance genes (ARGs) must be examined in tackling AMR in both humans and animals under the one health approach. Animal manure is recognized as an important source of AMR bacteria entering the environment, in which resistant genes can accumulate.

Methods

To gain a better understanding of the dissemination of third generation cephalosporin and fluoroquinolone resistance genes between isolates in the environment, we applied whole genome sequencing (WGS) to Enterobacterales (79 E. coli, 1 Enterobacter cloacae, 1 Klebsiella pneumoniae, and 1 Citrobacter gillenii) isolated from farm effluents in Ireland before (n = 72) and after (n = 10) treatment by integrated constructed wetlands (ICWs). DNA was extracted using the MagNA Pure 96 system (Roche Diagnostics, Rotkreuz, Switzerland) followed by WGS on a MiSeq platform (Illumina, Eindhoven, Netherlands) using v3 chemistry as 300-cycle paired-end runs. AMR genes and point mutations were identified and compared to the phenotypic results for better understanding of the mechanisms of resistance and resistance transmission.

Results

A wide variety of cephalosporin and fluoroquinolone resistance genes (mobile genetic elements (MGEs) and chromosomal mutations) were identified among isolates that mostly explained the phenotypic AMR patterns. A total of 31 plasmid replicon types were identified among the 82 isolates, with a subset of them (n = 24), identified in E. coli isolates. Five plasmid replicons were confined to the Enterobacter cloacae isolate and two were confined to the Klebsiella pneumoniae isolate. Virulence genes associated with functions including stress, survival, regulation, iron uptake secretion systems, invasion, adherence and toxin production were identified.

Conclusion

Our study showed that antimicrobial resistant organisms (AROs) can persist even following wastewater treatment and could transmit AMR of clinical relevance to the environment and ultimately pose a risk to human or animal health.

Methenamine hippurate to prevent recurrent urinary tract infections in older women: protocol for a randomised, placebo-controlled trial (ImpresU)

INTRODUCTION

Methenamine hippurate is a urinary antiseptic used as preventive treatment for recurrent urinary tract infections (UTIs) in some Scandinavian countries. However, the scientific evidence for the preventive effect and safety for longer-term use is limited. The aim of this study is to assess whether methenamine hippurate can reduce the incidence of UTIs in older women with recurrent UTIs.

METHODS AND ANALYSIS

The ImpresU consortium is a collaboration between Norway, Sweden, Poland and the Netherlands. The study is a randomised, controlled, triple-blind phase IV clinical trial. Women ≥70 years with recurrent UTIs are screened for eligibility in a general practice setting. We aim to include 400 women in total, with 100 recruited from each collaborating country. The participants are randomised to treatment with methenamine hippurate 1 g or placebo tablets two times per day for a treatment period of 6 months, followed by a drug-free follow-up period of 6 months. The primary outcome is number of antibiotic treatments for UTIs during the treatment period. The secondary outcomes include number of antibiotic treatments for UTIs during the follow-up period and self-reported symptom of severity and duration of UTI episodes. Differences in complications between the treatment groups are measured as safety outcomes. We also aim to investigate whether strain characteristics or phylogenetic subgroups of Escherichia coli present in the urine culture at inclusion have a modifying effect on the outcomes.

ETHICS AND DISSEMINATION

Ethical approvals are obtained in all participating countries. The results will be communicated in peer-reviewed journals and at scientific conferences.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT04077580); EudraCT: 2018-002235-15.

Antimicrobial Resistance, Virulence Factor-Encoding Genes, and Biofilm-Forming Ability of Community-Associated Uropathogenic Escherichia coli in Western Saudi Arabia

To explore the prevalence of multidrug-resistant community-associated uropathogenic Escherichia coli (UPEC) and their virulence factors in Western Saudi Arabia. A total of 1,000 urine samples were examined for the presence of E. coli by selective plating on MacConkey, CLED, and sheep blood agar. Antimicrobial susceptibility patterns were determined using Vitek^® 2 Compact (MIC) and the disc diffusion method with Mueller-Hinton agar. Genes encoding virulence factors (kpsMTII, traT, sat, csgA, vat, and iutA) were detected by PCR. The overall prevalence of UTI-associated E. coli was low, and a higher prevalence was detected in samples of female origin. Many of the isolates exhibited resistance to norfloxacin, and 60% of the isolates showed resistance to ampicillin. No resistance to imipenem, meropenem, or ertapenem was detected. In general, half of the isolates showed multiple resistance patterns. UPEC exhibited a weak ability to form biofilms, where no correlation was observed between multidrug resistance and biofilm-forming ability. All uropathogenic E. coli isolates carried the kpsMTII, iutA, traT, and csgA genes, whereas the low number of the isolates harbored the sat and vat genes. The diversity of virulence factors harbored by community-associated UPEC may render them more virulent and further explain the recurrence/relapse cases among community-associated UITs. To the best of our knowledge, this study constitutes the first exploration of virulence, biofilm-forming ability, and its association with multidrug resistance among UPEC isolates in Saudi Arabia. Further investigations are needed to elucidate the epidemiology of community-associated UPEC in Saudi Arabia.

Pathogenomics and clinical recurrence influence biofilm capacity of Escherichia coli isolated from canine urinary tract infections

Biofilm formation enhances bacteria’s ability to colonize unique niches while protecting themselves from environmental stressors. Escherichia coli that colonize the urinary tract can protect themselves from the harsh bladder environment by forming biofilms. These biofilms promote persistence that can lead to chronic and recurrent urinary tract infections (UTI). While biofilm formation is frequently studied among urinary E. coli, its association with other pathogenic mechanisms and adaptations in certain host populations remains poorly understood. Here we utilized whole genome sequencing and retrospective medical record analysis to investigate associations between the population structure, phenotypic resistance, resistome, virulome, and patient demographic and clinical findings of 104 unique urinary E. coli and their capacity to form biofilms. We show that population structure including multilocus sequence typing and Clermont phylogrouping had no association with biofilm capacity. Among clinical factors, exposure to multiple antibiotics within that past 30 days and a clinical history of recurrent UTIs were positively associated with biofilm formation. In contrast, phenotypic antimicrobial reduced susceptibility and corresponding acquired resistance genes were negatively associated with biofilm formation. While biofilm formation was associated with increased virulence genes within the cumulative virulome, individual virulence genes did not influence biofilm capacity. We identified unique virulotypes among different strata of biofilm formation and associated the presence of the tosA/R-ibeA gene combination with moderate to strong biofilm formation. Our findings suggest that E. coli causing UTI in dogs utilize a heterogenous mixture of virulence genes to reach a biofilm phenotype, some of which may promote robust biofilm capacity. Antimicrobial use may select for two populations, non-biofilm formers that maintain an arsenal of antimicrobial resistance genes to nullify treatment and a second that forms durable biofilms to avoid therapeutic insults.

The impact of the ST131 clone on recurrent ESBL-producing E. coli urinary tract infection: a prospective comparative study

The global emergence of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-E. coli), mainly causing urinary tract infections (UTI), is of great concern. Almost one third of patients with UTI, develop recurrent UTI (RUTI). We followed 297 patients for one year after their first episode of UTI due to ESBL-E. coli. Our aim was to evaluate the impact of the globally dominant sequence type (ST)131 clone and its clades, on the risk of subsequent recurrences with ESBL-E. coli. Isolates from patients developing RUTI (68/297) were compared with those from patients with sporadic UTI (SUTI, 229/297). No association was found between RUTI and the two most prevalent phylogroups B2 and D, bla_CTX-M genes, or resistance profile. Half of the patients with RUTI were infected with ST131 isolates. Clade C2 were in dominance (50/119) among ST131 isolates. They were more common in patients with RUTI than SUTI (28% vs 13%) and multivariate analysis showed an increased odds-ratio (OR = 2.21, p = 0.033) for recurrences in patients infected with these isolates as compared to non-ST131 isolates. Detecting specific biomarkers, as ST131 clade C2, in ESBL-E. coli UTI isolates may aid in prediction of RUTI and improve diagnostics and care of patients with a risk of ESBL-E. coli recurrences.

Phylogenetic Group Distribution of Uropathogenic Escherichia coli and Related Antimicrobial Resistance Pattern: A Meta-Analysis and Systematic Review

The phylogenetic classification of Escherichia coli isolates is of great importance not only for understanding the populations of E. coli but also for clarifying the relationship between strains and diseases. The present study aimed to evaluate the prevalence of phylogenetic groups, antibiotic susceptibility pattern, and virulence genes among uropathogenic E. coli (UPEC) isolated from different parts of Iran through a systematic review and meta-analysis. Several international electronic sources, including Web of Science, PubMed, Scopus, and Embase, were searched (2000–2020) in order to identify the studies compatible with our inclusion criteria. The meta-analysis was performed using the metaprop program in the STATA (version 11) software. Based on our comprehensive search, 28 studies meeting the eligibility criteria were included in the meta-analysis. The pooled prevalence of phylogroups B₂, D, B₁, and A was 39%, 26%, 18%, and 8%, respectively. In addition, there was a significant heterogeneity among different phylogroups. However, according to the results of Begg’s and Egger’s tests, there were no significant publication bias in phylogroups B₂, D, B₁, and A. This research provided the first comprehensive study on phylogroups of UPEC isolated in Iran. Our findings indicated that phylogroup B₂ and group D were the most predominant phylogenetic groups among UPEC isolates in various regions of Iran. In addition, we observed that certain phylogenetic groups are more antibiotic resistant than the others. It was also observed that the dissemination of virulent phylogroup B₂ and D should be controlled via comprehensive infection control measures. Additionally, certain strategies should be developed for monitoring the antibiotic therapy.

“Omics” Technologies - What Have They Told Us About Uropathogenic Escherichia coli Fitness and Virulence During Urinary Tract Infection?

Uropathogenic Escherichia coli (UPEC) is the main etiological agent of urinary tract infection (UTI), a widespread infectious disease of great impact on human health. This is further emphasized by the rapidly increase in antimicrobial resistance in UPEC, which compromises UTI treatment. UPEC biology is highly complex since uropathogens must adopt extracellular and intracellular lifestyles and adapt to different niches in the host. In this context, the implementation of forefront ‘omics’ technologies has provided substantial insight into the understanding of UPEC pathogenesis, which has opened the doors for new therapeutics and prophylactics discovery programs. Thus, ‘omics’ technologies applied to studies of UPEC during UTI, or in models of UTI, have revealed extensive lists of factors that are important for the ability of UPEC to cause disease. The multitude of large ‘omics’ datasets that have been generated calls for scrutinized analysis of specific factors that may be of interest for further development of novel treatment strategies. In this review, we describe main UPEC determinants involved in UTI as estimated by ‘omics’ studies, and we compare prediction of factors across the different ‘omics’ technologies, with a focus on those that have been confirmed to be relevant under UTI-related conditions. We also discuss current challenges and future perspectives regarding analysis of data to provide an overview and better understanding of UPEC mechanisms involved in pathogenesis which should assist in the selection of target sites for future prophylaxis and treatment.

Genetic diversity and virulence characteristics of biofilm-producing uropathogenic Escherichia coli

Uropathogenic E. coli (UPEC) strains exhibit different levels of biofilm formation that help adhesion of the bacteria to uroepithelial cells. We investigated the genetic diversity and virulence-associated genes (VAGs) of biofilm-producing UPEC. A collection of 107 biofilm-producing (BFP) UPEC strains isolated from patients with UTI in Iran were divided into three groups of strong, moderate, and weak BFPs after a quantitative microtiter plate assay, and the involvement of curli and cellulose in adhesion of the strains to T24 cell line was confirmed by the construction of csgD and yedQ mutants of two representative UPEC strains. BFP strains were tested for their genetic diversity, phylogenetic groups, and the presence of 15 VAGs. A significant decrease in adhesion of csgD and yedQ mutant strains confirmed the role of biofilm production in adhesion to uroepithelial cells. A high diversity was found among all three groups of strong (Di = 0.998), moderate (Di = 0.998), and weak (Di = 0.988) BFPs with majority of the strains belonging to phylogroups B2 (44.9%) and A (24.3%). Strong BFP strains carried significantly higher level papEF, hlyA, and iutA than other BFP groups. In contrast, the presence of fimH, focG, sfaS, set-1, and cvaC was more pronounced among weak BFP strains. There exists a high genetic diversity among the BFP strains with different VGA profiles. However, the high prevalence of phylogroup A among BFP strains suggests the fitness of commensal E. coli strains to cause UTI in this country.

Changes of urine isolates of Escherichia coli and Klebsiella pneumoniae biofilm affect monocytes' response

The Gram negative rods as Escherichia coli and Klebsiella pneumoniae belong to the most common etiology agents of urinary tract infections. The aim of our study was to assess the diversity of biofilm formed in different urinary tract diseases and their impact on monocytes’ adherence and activation. The bacteria were obtained from patients with different kidney problems. Some of the patients were after renal transplantation, some of them were not. Changes in the size and granularity of monocytes, as well as their adherence to biofilm, were assessed using FACSVerse flow cytometer after 1 h co-incubation of monocytes and bacterial biofilm in 37 °C. The obtained results were validated against monocytes incubated without bacteria. The isolates from patients with chronic kidney disease formed the most adherent biofilm regardless the presence or absence of inflammatory reaction. Adherence of monocytes also increased during therapy with immunosuppressive agents, but monocytes’ response was different when cyclosporine or tacrolimus were used. Additionally the presence of inflammatory reaction in patients with kidney disease modified the monocytes response when the immunosuppressive drugs were used. Considering the obtained results, we conclude that the changes of monocytes’ morphology in response to biofilm formed by Gram negative rods could become a tool to detect urinary tract infection, especially in those groups of patients, where the knowledge of ongoing inflammation is important and the standard tools fail to detect it.

Antimicrobial Resistance and Molecular Epidemiology of Uropathogenic Escherichia coli Isolated From Female Patients in Shanghai, China

Urinary tract infection (UTI) is one of the most common bacterial infections and UTI is the most common extraintestinal infectious disease entity in women worldwide. Uropathogenic Escherichia coli (UPEC) is the leading cause of UTI. While antimicrobial resistance has emerged as one of the principal problems of UTI, little is known about the epidemiology of UPEC isolated from female patients in Shanghai. This study aimed to describe the antimicrobial resistance and molecular epidemiology of UPEC isolated from female patients in Shanghai, China. UPEC isolates were collected from female patients from July 2019 to June 2020 in Shanghai and a total of 151 isolates were obtained randomly. Antimicrobial susceptibility testing was performed using the disk diffusion method. Multilocus sequencing type, phylogenetic groups, antimicrobial resistance genes, and virulence genes were detected by polymerase chain reaction. In our study, no carbapenem-resistant isolates were found, but fluoroquinolone-resistant and multi-drug resistant UPEC accounted for 62.25% and 42.38%, respectively. The phylogenetic group B2 (58.94%) predominated, followed by phylogenetic group D (26.49%). The most prevalent sequence type was ST1193 (25.83%), which was first reported in Shanghai. The rate of extended-spectrum β-lactamase (ESBL)-positive isolates was 39.74% and the dominant ESBL genotype was bla_CTX-M-14 (21/60), followed by bla_CTX-M-55 (12/60). Mutations in gyrA were detected in the majority of fluoroquinolone-resistant isolates (90/94), followed by parC (85/94) and parE (71/94). The aac (3) -IIa was also found in 85% of aminoglycoside resistance isolates. Among 151 UPEC isolates, the common virulence genes were csgA (97.35%), fimH (92.72%), sitA (82.12%), and malX (65.56%). In conclusion, the high antimicrobial resistance of UPEC isolated from female patients, harboring a series of virulence genes, are troublesome for medical practitioners in Shanghai. At present, the prevalent ST1193 and emerging bla_CTX-M-55 make UTI therapy more challenging.

Biofilm formation by uropathogenic Escherichia coli: a complicating factor for treatment and recurrence of urinary tract infections

BACKGROUND

Uropathogenic Escherichia coli (UPEC) are the principal cause of urinary tract infections (UTIs) which can be either hospital- or community-acquired. The most crucial factor in the persistence and recurrence of UTIs is the biofilm formation ability of UPEC, which protects them against antimicrobial treatment.

AIM

To investigate the genetic relatedness, biofilm formation ability, and biofilm-related genes in UPEC isolated from hospital- and community-acquired UTI patients.

METHODS

In vitro biofilm formation ability of 100 UPEC isolates, collected from the urine samples of 49 inpatients and 51 outpatients with UTIs, was assessed by the microtitre plate method. The association between the presence of fimH, papC, sfa/focDE, csgA, crl, afa, flu, and bcsA genes and biofilm formation ability of UPEC was statistically analysed. The genetic relatedness of UPEC isolates was evaluated by enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR).

FINDINGS

Overall, 99% of the UPEC isolates showed in vitro biofilm formation ability, and 27% of the isolates were moderate to strong biofilm producers. Only the presence of sfa/focDE gene was significantly associated with moderate and strong biofilm formation by the UPEC isolates. Analysis of dendrograms revealed higher genetic similarities among UPEC isolates of inpatients compared with outpatients.

CONCLUSION

Based on the results, selection of effective therapeutic approaches, which can affect both biofilm formation and enclosed UPEC, is important for preventing recurrent UTIs. The common UPEC clones among inpatients in different hospital units emphasize the need for more rigid control measures to prevent the spread of UPEC in hospitalized patients and to reduce the occurrence of hospital-acquired UTIs.

Virulence genes and phylogenetic groups of uropathogenic Escherichia coli isolates from patients with urinary tract infection and uninfected control subjects: a case-control study

Background

Urinary Tract Infection (UTI) is one of the most common bacterial infectious diseases which causes considerable morbidity and costly health problems. Uropathogenic Escherichia coli (UPEC), the most common pathogen causing UTI, is a highly heterogeneous group of extraintestinal pathogenic E. coli (ExPEC) which may carry a variety of virulence factors and belonging to different phylogenetic backgrounds. The current study aimed to investigate the frequency and association between various virulence factors (VFs) and phylogenetic groups of UPEC and commensal isolates.

Methods

UPEC and commensal E. coli strains isolated from UTI and feces of healthy humans were compared for the presence of VFs and phylogenetic groups. Association between virulence genes was investigated and cluster analysis was employed.

Results

According to the results, among a 30 virulence markers tested, the pathogenicity-associated island (PAI), papAH, papEF, fimH, fyuA, and traT genes prevalence were statistically significant in UPEC isolates. A strong association was found between the B2 and D phylogenetic groups and clinical isolates of UPEC; while, commensal isolates were mostly associated with phylogenetic group A. The aggregated VFs scores were more than twice higher in the UPEC isolates in comparison with the commensal isolates. Interestingly, the B2 group in both UPEC and commensal isolates had the highest VF scores. A strong positive association was found between several virulence genes. The clustering results demonstrated that UPEC or commensal E. coli isolates were highly heterogeneous due to different composition of their virulence gene pool and pathogenicity islands.

Conclusion

Genetic structure and VFs of UPEC strains vary from region to region; therefore, to control the UTI, the epidemiological aspects and characterization of the UPEC isolates need to be investigated in different regions. Since UPEC isolates are generally originate from the commensal strains, it may be feasible to reduce the UTI burden by interfering the intestinal colonization, particularly in the highly pathogenic clonal lineages such as B2.

High dose versus low dose standardized cranberry proanthocyanidin extract for the prevention of recurrent urinary tract infection in healthy women: a double-blind randomized controlled trial

PURPOSE

Our objective was to assess the efficacy of a high dose cranberry proanthocyanidin extract for the prevention of recurrent urinary tract infection.

MATERIAL AND METHODS

We recruited 145 healthy, adult women with a history of recurrent urinary tract infection, defined as ≥ 2 in the past 6 months or ≥ 3 in the past 12 months in this randomized, controlled, double-blind clinical trial. Participants were randomized to receive a high dose of standardized, commercially available cranberry proanthocyanidins (2 × 18.5 mg daily, n = 72) or a control low dose (2 × 1 mg daily, n = 73) for a 24-week period. During follow-up, symptomatic women provided urine samples for detection of pyuria and/or bacteriuria and received an appropriate antibiotic prescription. The primary outcome for the trial was the mean number of new symptomatic urinary tract infections during a 24-week intervention period. Secondary outcomes included symptomatic urinary tract infection with pyuria or bacteriuria.

RESULTS

In response to the intervention, a non-significant 24% decrease in the number of symptomatic urinary tract infections was observed between groups (Incidence rate ratio 0.76, 95%CI 0.51-1.11). Post-hoc analyses indicated that among 97 women who experienced less than 5 infections in the year preceding enrolment, the high dose was associated with a significant decrease in the number of symptomatic urinary tract infections reported compared to the low dose (age-adjusted incidence rate ratio 0.57, 95%CI 0.33-0.99). No major side effects were reported.

CONCLUSION

High dose twice daily proanthocyanidin extract was not associated with a reduction in the number of symptomatic urinary tract infections when compared to a low dose proanthocyanidin extract. Our post-hoc results reveal that this high dose of proanthocyanidins may have a preventive impact on symptomatic urinary tract infection recurrence in women who experienced less than 5 infections per year.

TRIAL REGISTRATION

Clinicaltrials.gov, identifier NCT02572895.

Asymptomatic Bacteriuria (ABU) in Elderly: Prevalence, Virulence, Phylogeny, Antibiotic Resistance and Complement C3 in Urine

Background: The incidence of asymptomatic bacteriuria (ABU) increases with age and is most common for persons 80 years of age and above and in elderly living in nursing homes. The distinction between ABU and urinary tract infection (UTI) is often difficult, especially in individuals, who are unable to communicate their symptoms, and there is a lack of objective methods to distinguish between the two entities. This can lead to overuse of antibiotics, which results in the selection and dissemination of antibiotic resistant isolates. Materials and methods: From voided midstream urine samples of 211 participants ≥60 years old from nursing homes, an activity center and a general practitioners clinic, we collected 19 ABU, 16 UTI and 22 control urine samples and compared them with respect to levels of complement component C3 in urine as determined by an ELISA assay relative to creatinine levels in the same urine samples, as measured by a creatinine assay. Further, we studied all Escherichia coli isolates for selected virulence genes by multiplex PCR, and by whole-genome sequencing (WGS) for genotypes and phylogenetic clustering. Antibiotic susceptibility was determined by microtiter broth dilution. Results: We identified a prevalence of ABU of 18.9% in nursing home residents, whereas ABU was only found in 4% of elderly living in the community (p < 0.001). E. coli from ABU patients were significantly more antibiotic resistant than E. coli from UTIs (p = 0.01). Prevalence of classical virulence genes, detected by multiplex PCR, was similar in E. coli isolates from ABU and UTI patients. Whole-genome sequencing of the E. coli isolates showed no specific clustering of ABU isolates compared to UTI isolates. Three isolates from three different individuals from one of the nursing homes showed signs of transmission. We demonstrated a significantly increased level of C3/creatinine ratio in ABU and UTI samples compared to healthy controls; however, there was no significant difference between the ABU and UTI group with respect to C3 level, or virulence factor genes. Conclusion: ABU was significantly more prevalent in the elderly residing in nursing homes than in the elderly living at home. Antibiotic resistance was more prevalent in E. coli from nursing homes than in UTI isolates, but there was no difference in prevalence of virulence associated genes between the two groups and no phylogenetic clustering, as determined by WGS relative to the two types of E. coli bacteriuria. The similar complement C3 response in ABU and UTI patients may indicate that ABU should be reconsidered as an infection albeit without symptoms.

Extracellular DNA, cell surface proteins and c-di-GMP promote biofilm formation in Clostridioides difficile

Clostridioides difficile is the leading cause of nosocomial antibiotic-associated diarrhoea worldwide, yet there is little insight into intestinal tract colonisation and relapse. In many bacterial species, the secondary messenger cyclic-di-GMP mediates switching between planktonic phase, sessile growth and biofilm formation. We demonstrate that c-di-GMP promotes early biofilm formation in C. difficile and that four cell surface proteins contribute to biofilm formation, including two c-di-GMP regulated; CD2831 and CD3246, and two c-di-GMP-independent; CD3392 and CD0183. We demonstrate that C. difficile biofilms are composed of extracellular DNA (eDNA), cell surface and intracellular proteins, which form a protective matrix around C. difficile vegetative cells and spores, as shown by a protective effect against the antibiotic vancomycin. We demonstrate a positive correlation between biofilm biomass, sporulation frequency and eDNA abundance in all five C. difficile lineages. Strains 630 (RT012), CD305 (RT023) and M120 (RT078) contain significantly more eDNA in their biofilm matrix than strains R20291 (RT027) and M68 (RT017). DNase has a profound effect on biofilm integrity, resulting in complete disassembly of the biofilm matrix, inhibition of biofilm formation and reduced spore germination. The addition of exogenous DNase could be exploited in treatment of C. difficile infection and relapse, to improve antibiotic efficacy.

The gene profile of Enterobacteriaceae virulence factors in relation to bacteriuria levels between the acute episodes of recurrent uncomplicated lower urinary tract infection

OBJECTIVES

The pathogenic potential of uropathogens isolated between acute episodes of recurrent lower urinary tract infection (rLUTI) is studied insufficiently. The objectives were to determine the spectrum of virulence genes of Enterobacteriaceae cultured between acute episodes of rLUTI at various levels of bacteriuria.

METHODS

Bacteriological examinations of 169 premenopausal women's midstream urine with rLUTI were performed between acute episodes of UTI. Sixty-two strains of Enterobacteriaceae at concentrations 10²-10⁸ CFU/ml were analyzed for the presence of papA, papE/F, papGII, afa, bmaE, iutA, feoB, fyuA, kpsMTII, and usp virulence factors genes' (VFGs) fragments.

RESULTS

In all strains VFGs were found with numbers from 1 to 10. Four VFGs were found at all levels of bacteriuria (from 10² to 10^7-8) in most strains (>50%): papGII, feoB, fyuA, usp. In total, 28 significant Pearson contingency coefficient (PCC) were determined. Each of the genes, papA, papE/F, usp, was found more often in uropathogens from patients with a higher level of leukocyturia.

CONCLUSIONS

The inter-episode period in rLUTI is associated with varying levels of bacteriuria of enterobacteria. Since enterobacteria virulent potential could be determined at all levels of bacteriuria, there is at all levels of bacteriuria a potential risk for recurrence of LUTI.

Distribution of phylogenetic groups, adhesin genes, biofilm formation, and antimicrobial resistance of uropathogenic Escherichia coli isolated from hospitalized patients in Thailand

Background

Urinary tract infections (UTIs) are the most common bacterial infections and are often caused by uropathogenic Escherichia coli (UPEC). We investigated the distribution of phylogenetic groups, adhesin genes, antimicrobial resistance, and biofilm formation in E. coli isolated from patients with UTIs.

Methods

In the present study, 208 UPEC isolated from Thai patients were classified into phylogenetic groups and adhesin genes were detected using multiplex PCR. Antimicrobial susceptibility testing was performed using agar disk diffusion. The Congo red agar method was used to determine the ability of the UPEC to form biofilm.

Results

The most prevalent UPEC strains in this study belonged to phylogenetic group B2 (58.7%), followed by group C (12.5%), group E (12.0%), and the other groups (16.8%). Among adhesin genes, the prevalence of fimH (91.8%) was highest, followed by pap (79.3%), sfa (12.0%), and afa (7.7%). The rates of resistance to fluoroquinolones, trimethoprim-sulfamethoxazole, and amoxicillin-clavulanate were  65%, 54.3%, and 36.5%, respectively. The presence of adhesin genes and antibiotic resistance were more frequent in groups B2 and C compared to the other groups. Of the 129 multidrug-resistant UPEC strains, 54% were biofilm producers. Our findings further indicated that biofilm production was significantly correlated with the pap adhesin gene (p ≤ 0.05).

Conclusion

These findings provide molecular epidemiologic data, antibiotic resistance profiles, and the potential for biofilm formation among UPEC strains that can inform further development of the appropriate prevention and control strategies for UTIs in this region.

Horizontally acquired papGII-containing pathogenicity islands underlie the emergence of invasive uropathogenic Escherichia coli lineages

Escherichia coli is the leading cause of urinary tract infection, one of the most common bacterial infections in humans. Despite this, a genomic perspective is lacking regarding the phylogenetic distribution of isolates associated with different clinical syndromes. Here, we present a large-scale phylogenomic analysis of a spatiotemporally and clinically diverse set of 907 E. coli isolates, including 722 uropathogenic E. coli (UPEC) isolates. A genome-wide association approach identifies the (P-fimbriae-encoding) papGII locus as the key feature distinguishing invasive UPEC, defined as isolates associated with severe UTI, i.e., kidney infection (pyelonephritis) or urinary-source bacteremia, from non-invasive UPEC, defined as isolates associated with asymptomatic bacteriuria or bladder infection (cystitis). Within the E. coli population, distinct invasive UPEC lineages emerged through repeated horizontal acquisition of diverse papGII-containing pathogenicity islands. Our findings elucidate the molecular determinants of severe UTI and have implications for the early detection of this pathogen.

Genetic and Virulence Characteristics of a Hybrid Atypical Enteropathogenic and Uropathogenic Escherichia coli (aEPEC/UPEC) Strain

Hybrid strains of Escherichia coli combine virulence traits of diarrheagenic (DEC) and extraintestinal pathogenic E. coli (ExPEC), but it is poorly understood whether these combined features improve the virulence potential of such strains. We have previously identified a uropathogenic E. coli (UPEC) strain (UPEC 252) harboring the eae gene that encodes the adhesin intimin and is located in the locus of enterocyte effacement (LEE) pathogenicity island. The LEE-encoded proteins allow enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) to form attaching and effacing (A/E) lesions in enterocytes. We sought to characterize UPEC 252 through whole-genome sequencing and phenotypic virulence assays. Genome analysis unveiled that this strain harbors a complete LEE region, with more than 97% of identity comparing to E2348/69 (EPEC) and O157:H7 Sakai (EHEC) prototype strains, which was functional, since UPEC 252 expressed the LEE-encoded proteins EspB and intimin and induced actin accumulation foci in HeLa cells. Phylogenetic analysis performed comparing 1,000 single-copy shared genes clustered UPEC 252 with atypical EPEC strains that belong to the sequence type 10, phylogroup A. Additionally, UPEC 252 was resistant to the bactericidal power of human serum and colonized cells of the urinary (T24 and HEK293-T) and intestinal (Caco-2 and LS174T) tracts. Our findings suggest that UPEC 252 is an atypical EPEC strain that emerges as a hybrid strain (aEPEC/UPEC), which could colonize new niches and potentially cause intestinal and extraintestinal infections.

Pathogenicity Factors of Genomic Islands in Intestinal and Extraintestinal Escherichia coli

Escherichia coli is a versatile bacterial species that includes both harmless commensal strains and pathogenic strains found in the gastrointestinal tract in humans and warm-blooded animals. The growing amount of DNA sequence information generated in the era of "genomics" has helped to increase our understanding of the factors and mechanisms involved in the diversification of this bacterial species. The pathogenic side of E. coli that is afforded through horizontal transfers of genes encoding virulence factors enables this bacterium to become a highly diverse and adapted pathogen that is responsible for intestinal or extraintestinal diseases in humans and animals. Many of the accessory genes acquired by horizontal transfers form syntenic blocks and are recognized as genomic islands (GIs). These genomic regions contribute to the rapid evolution, diversification and adaptation of E. coli variants because they are frequently subject to rearrangements, excision and transfer, as well as to further acquisition of additional DNA. Here, we review a subgroup of GIs from E. coli termed pathogenicity islands (PAIs), a concept defined in the late 1980s by Jörg Hacker and colleagues in Werner Goebel's group at the University of Würzburg, Würzburg, Germany. As with other GIs, the PAIs comprise large genomic regions that differ from the rest of the genome by their G + C content, by their typical insertion within transfer RNA genes, and by their harboring of direct repeats (at their ends), integrase determinants, or other mobility loci. The hallmark of PAIs is their contribution to the emergence of virulent bacteria and to the development of intestinal and extraintestinal diseases. This review summarizes the current knowledge on the structure and functional features of PAIs, on PAI-encoded E. coli pathogenicity factors and on the role of PAIs in host-pathogen interactions.

Prevalence of some virulence factors and genotyping of hospital-acquired uropathogenic Escherichia coli isolates recovered from cancer patients

OBJECTIVES

This study aimed to determine the prevalence of virulence factors among uropathogenic Escherichia coli (UPEC) isolates from cancer patients and to investigate their genetic diversity using ERIC-PCR.

METHODS

A total of 42 E. coli were recovered from urine samples from cancer patients admitted to Assiut University Hospital. PCR was used to detect the presence of three virulence genes (papC, iutA and cnf1). Genetic diversity of the isolates was determined using the ERIC-PCR fingerprinting method, and amplified products were separated by agarose gel electrophoresis. Gel electrophoresis banding patterns were used for dendrogram generation using NTSYSpc software.

RESULTS

Among the 42 UPEC isolates, papC was the most common virulence gene (55% of isolates), followed by iutA (38%) and cnf1 (2%). ERIC-PCR successfully produced multiple amplicons (range 2-11 bands) in each strain, with molecular weights ranging from 285 to 3000 bp. Some UPEC isolates had identical ERIC-PCR profiles (identical banding patterns), whilst 22 UPEC isolates had different ERIC-PCR profiles. The phylogenetic dendrogram of ERIC-PCR showed that the 42 isolates can be differentiated into three major clusters (I, II and III), with cluster I representing 76% of isolates, cluster II representing 19% and cluster III representing 5%.

CONCLUSIONS

The results of this study suggest that both papC and iutA genes may have an important role in the pathogenesis of overt urinary tract infection. Dendrogram analysis of the ERIC-PCR profiles revealed that all UPEC isolates were assigned into three main clusters, indicating the spread of distinct clonal groups that are responsible for hospital-acquired infections.

[Phylogenetic groups and virulence genes of Escherichia coli strains isolated from the children gut microbiota.]

Escherichia coli is characterized by a wide intraspecific diversity. The species includes both commensals and pathogens that cause diarrhea and extra-intestinal diseases. Pathogenic strains differ from non-pathogenic ones by the presence of virulence factors and their genes. The phylogenetic structure of the species is represented by four main groups (A, B1, B2, D), which differ in their prevalence among residents of different geographical regions. Pathogenic members of the species have been studied in detail, while non-pathogenic strains have not received such attention. This report presents the results of a study of 511 E. coli strains isolated from the gut microbiota of children without diarrhea and urinary tract infections, aged from 1 month to 17 years, living in St. Petersburg. The main phylogenetic groups were determined by PCR, and E. coli virulence genes associated with diarrhea and extra-intestinal diseases were identified. Results: population structure of E. coli is represented by the following groups: A-33.3%, B1-6.7%, B2-34.0%, D-26%. In the studied population 2.5% of strains belonded to EPEC and 4.5% to EAggEC. EPEC virulence genes were more often detected in strains of phylogroup B1, and EAggEC virulence genes in isolates of phylogroup D. The prevalence of extra - intestinal virulence genes was as follows: pap - 29.5%; sfa - 19.8%; afa - 3.3%; hly - 20.9%; cnf - 17.4%; aer-20.0%. The pap, sfa, hly, and cnf genes were detected mostly in the B2 phylogenetic group. Obtained data shows the similarity of E. coli phylogenetic groups structure in St. Petersburg with E. coli populations isolated from residents of Paris and Sydney. Analysis of the virulence genes prevalence showed the dependence of their presence on the genetic background bacteria.

Genetic diversity, antimicrobial resistance and extended-spectrum β-lactamase type of Escherichia coli isolates from chicken, dog, pig and yak in Gansu and Qinghai Provinces, China

OBJECTIVES

In this study, the genetic diversity, phylogenetic grouping, antimicrobial resistance and extended-spectrum β-lactamase (ESBL) types of Escherichia coli isolates from chickens, dogs, pigs and yaks in six prefectures of Gansu and Qinghai Provinces, China, were investigated.

METHODS

E. coli was isolated from diarrhoeic and healthy faecal samples. Multilocus sequence typing (MLST), phylogenetic grouping, antimicrobial resistance and ESBL profiles were investigated.

RESULTS

A total of 142 MLST sequence types (STs) were identified from 400 E. coli isolates. eBURST clustering analysis resolved the 142 STs into 19 clonal complexes (CCs) and 67 singletons. PCR phylogenetic typing determined the isolation rate of potentially pathogenic B2/D group isolates among all E. coli to be 12.5% from healthy animal samples and 17.5% from diarrhoeic samples. Antimicrobial susceptibility testing revealed 78 antimicrobial resistance patterns. E. coli resistance rates were highest to doxycycline, ampicillin and tetracycline, whereas polymyxin B and meropenem had the lowest resistance rates. All polymyxin B-resistant E. coli isolates were positive for the mcr-1 gene. A total of 62 ESBL-producing isolates were identified. The ESBL prevalence was 55.0% in diarrhoeic samplings and 5.6% in healthy animals. TEM (82.3%) was the predominant ESBL type, followed by CTM (43.5%) and SHV (19.4%).

CONCLUSION

E. coli isolates in the study area have a high diversity of genetic and antimicrobial resistance patterns but a relatively low isolation rate of potentially pathogenic phylogroups. However, the somewhat high isolation rate of multidrug-resistant E. coli, particularly ESBL-producing isolates, requires continual surveillance of E. coli from animals in these areas.

A Nanostructured Gold/Graphene Microfluidic Device for Direct and Plasmonic-Assisted Impedimetric Detection of Bacteria

Hierarchical 3D gold nano-/microislands (NMIs) are favorably structured for direct and probe-free capture of bacteria in optical and electrochemical sensors. Moreover, their unique plasmonic properties make them a suitable candidate for plasmonic-assisted electrochemical sensors, yet the charge transfer needs to be improved. In the present study, we propose a novel plasmonic-assisted electrochemical impedimetric detection platform based on hybrid structures of 3D gold NMIs and graphene (Gr) nanosheets for probe-free capture and label-free detection of bacteria. The inclusion of Gr nanosheets significantly improves the charge transfer, addressing the central issue of using 3D gold NMIs. Notably, the 3D gold NMIs/Gr detection platform successfully distinguishes between various types of bacteria including Escherichia coli (E. coli) K12, Pseudomonas putida (P. putida), and Staphylococcus epidermidis (S. epidermidis) when electrochemical impedance spectroscopy is applied under visible light. We show that distinguishable and label-free impedimetric detection is due to dissimilar electron charge transfer caused by various sizes, morphologies, and compositions of the cells. In addition, the finite-difference time-domain (FDTD) simulation of the electric field indicates the intensity of charge distribution at the edge of the NMI structures. Furthermore, the wettability studies demonstrated that contact angle is a characteristic feature of each type of captured bacteria on the 3D gold NMIs, which strongly depends on the shape, morphology, and size of the cells. Ultimately, exposing the platform to various dilutions of the three bacteria strains revealed the ability to detect dilutions as low as ∼20 CFU/mL in a wide linear range of detection of 2 × 10¹-10⁵, 2 × 10¹-10⁴, and 1 × 10²-1 × 10⁵ CFU/mL for E. coli, P. putida, and S. epidermidis, respectively. The proposed hybrid structure of 3D gold NMIs and Gr, combined by novel plasmonic and conventional impedance spectroscopy techniques, opens interesting avenues in ultrasensitive label-free detection of bacteria with low cost and high stability.

Multiple Drug Resistance Patterns in Various Phylogenetic Groups of Hospital-Acquired Uropathogenic E. coli Isolated from Cancer Patients

Cancer patients are more susceptible to several bacterial infections, particularly urinary tract infections caused by uropathogenic E. coli (UPEC). The objective of this work was detection and the phylogenetic characterization of hospital-acquired isolates of uropathogenic E. coli in cancer patients and the determination of its relation with antibiotic resistance. A total of 110 uropathogenic E. coli responsible for hospital-acquired urinary tract infections in cancer patients were included in this study. A triplex PCR was employed to segregate different isolates into four different phylogenetic groups (A, B1, B2 and D). Drug resistance was evaluated by the disc diffusion method. All of the isolates were multiple drug-resistant (MDR) and 38.18% of all UPEC isolates were extended-spectrum beta-lactamase (ESBL) producers from which 52% were positive for the blaCTX-M gene, 40% for the blaTEM gene, and 17% for the blaSHVgene. Among 42 ESBL-producing uropathogenic E. coli isolates, the majority belonged to phylogenetic group B2 (43%), followed by group D (36%), group A (19%) and group B1 (2%). Our results have shown the emergence of MDR isolates among uropathogenic E. coli with the dominance of phylogenetic group B2. Groups A and B1 were relatively less common. The most effective drug in all phylogenetic groups was imipenem.

Behavioral and dietary risk factors of recurrent urinary tract infection in Chinese postmenopausal women: a case-control study

OBJECTIVE

The present study aimed to examine the behavioral and dietary risk factors of recurrent urinary tract infection (RUTI) in postmenopausal patients in China.

METHODS

We performed a population-based case-control study with 193 postmenopausal women with RUTI and 193 age-matched healthy female controls with no history of RUTI. The study was conducted between January 2016 and June 2018 in Changzhou, China. Data were collected using an interviewer-based questionnaire, including information on demographics, lifestyle behavior, and habitual diet. Conditional logistic regression analysis was conducted to examine the risk factors associated with RUTI.

RESULTS

Wiping from back to front after toilet use, sedentary behavior >6 hours/day, delayed voiding, and chronic constipation were associated with an increased risk of RUTI. Drinking more than three cups of green tea per month showed an inverse association with RUTI. However, there was no evidence of dose dependency for overall consumption. Additionally, the three-cup association involved a small proportion of cases and may reflect statistical artifact.

CONCLUSIONS

Wiping from back to front after toilet use, sedentary behavior, delayed voiding, and chronic constipation are associated with an increased risk of RUTI in postmenopausal women.

Urinary tract infections: microbial pathogenesis, host-pathogen interactions and new treatment strategies

Urinary tract infections (UTIs) are common, recurrent infections that can be mild to life-threatening. The continued emergence of antibiotic resistance, together with our increasing understanding of the detrimental effects conferred by broad-spectrum antibiotic use on the health of the beneficial microbiota of the host, has underscored the weaknesses in our current treatment paradigm for UTIs. In this Review, we discuss how recent microbiological, structural, genetic and immunological studies have expanded our understanding of host-pathogen interactions during UTI pathogenesis. These basic scientific findings have the potential to shift the strategy for UTI treatment away from broad-spectrum antibiotics targeting conserved aspects of bacterial replication towards pathogen-specific antibiotic-sparing therapeutics that target core determinants of bacterial virulence at the host-pathogen interface.

Distribution of virulence genes and phylogenetics of uropathogenic Escherichia coli among urinary tract infection patients in Addis Ababa, Ethiopia

Background

Urinary tract infection (UTI) is a common cause of morbidity worldwide. Uropathogenic Escherichia coli (UPEC) bacteria are the major cause of urinary tract infections. UPEC strains derive from different phylogenetic groups and possess an arsenal of virulence factors that contribute to their ability to overcome different defense mechanisms and cause disease. The objective of this study was to identify phylogroup and virulence genes of UPEC among urinary tract infection patients.

Methods

A cross sectional study was conducted from January 1, 2017 to October 9, 2017. E. coli bacteria were isolated from UTI patients using culture and conventional biochemical tests. Identification of phylogroup and genes that encodes for virulence factors was done using multiplex polymerase chain reaction (PCR). Data was processed and analyzed with SPSS version16.0 and Epi-info version 3.4.1 software.

Results

The most common urologic clinical manifestation combinations in this study were dysuria, urine urgency and urgency incontinence. The frequent UPEC virulence gene identified was fimH 164 (82%), followed by aer 109 (54.5%), hly 103 (51.5%), pap 59 (29.5%), cnf 58 (29%), sfa 50 (25%) and afa 24 (12%).There was significant association between pap gene and urine urgency (p-0.016); sfa and dysuria and urine urgency (p-0.019 and p-0.043 respectively); hly and suprapubic pain (p-0.002); aer and suprapubic pain, flank pain and fever (p-0.017, p-0.040, p-0.029 respectively). Majority of E. coli isolates were phylogroup B2 60(30%) followed by D 55(27.5%), B1 48(24%) and A 37(18.5%). There was significant association between E. coli phylogroup B2 and three virulence genes namely afa, pap, and sfa (p-0.014, p-0.002, p-0.004 respectively).

Conclusion

In this study the most frequent E. coli virulence gene was fimH, followed by aer, hly, pap, cnf, sfa and afa respectively. There was significant association between E. coli virulence genes and clinical symptoms of UTI. The phylogenetic analysis indicates majority of uropathogenic E. coli isolates were phylogroup B2 followed by phylogroup D. Phylogroup B2 carries more virulence genes. Hence, targeting major UPEC phylogroup and virulence genes for potential vaccine candidates is essential for better management of UTI and further research has to be conducted in this area.

Phylogenetic groups and antimicrobial susceptibility patterns of uropathogenic Escherichia coli clinical isolates from patients at Mulago National Referral Hospital, Kampala, Uganda

Introduction: Uropathogenic Escherichia coli (UPEC) remains the most common cause of urinary tract infections (UTIs). They account for over 80-90% of all community-acquired and 30-50% of all hospital-acquired UTIs. E. coli strains have been found to belong to evolutionary origins known as phylogenetic groups. In 2013, Clermont classified E. coli strains into eight phylogenetic groups using the quadruplex PCR method. The aim of this study was to identify the phylogenetic groups of UPEC strains in Uganda using Clermont’s quadruplex PCR method and to assess their antibiotic susceptibility patterns in Uganda. Methods: In this cross-sectional study, 140 stored uropathogenic E. coli isolates from the Clinical Microbiology Laboratory, Department of Medical Microbiology, College of Health Sciences Makerere University were subjected to phylogenetic typing by a quadruplex PCR method. Antimicrobial susceptibility testing was performed by disk diffusion method according to Clinical & Laboratory Standards Institute (CLSI) guidelines. Phenotypic detection of extended-spectrum beta-lactamase, AmpC and carbapenemases was done according to CLSI guidelines and Laboratory SOPs. Results: Phylogenetic group B2 (40%) was the most predominant, followed by A (6.23%), clade I and II (5%), D and E (each 2.14%), B1 (1.43%) and F and C (each 0.71%). The most common resistant antibiotic was trimethoprim-sulphamethoxazole (90.71%) and the least was imipenem (1.43%). In total, 73.57% of isolates were multi-drug resistant (MDR). Antibiotic resistance was mainly detected in phylogenetic group B2 (54%). Conclusions: Our findings showed the high prevalence of MDR E. coli isolates, with the dominance of phylogenetic group B2. About 9% of E. coli isolates belonged to the newly described phylogroups C, E, F, and clade I and II.

In-Vitro Biofilm Formation and Antimicrobial Resistance of Escherichia coli in Diabetic and Nondiabetic Patients

Background

Diabetic patients are more susceptible to urinary tract infection compared to nondiabetic patients, Escherichia coli being the most common uropathogen causing UTI. Unreasonable and incorrect antibiotic prescription for UTI in these patients may induce the development of antibiotic-resistant urinary pathogens resulting in delayed recovery and longer hospitalization. In addition to these, biofilm forming capacity of the pathogen may worsen the problem. The main aim of this cross-sectional study (conducted from March to September 2015) is to detect the biofilm forming capacity of UTI causing micro-organisms and compare the antibiotic resistance pattern of Escherichia coli, the most common cause of UTI, which will help the physician in choosing the best antibiotic.

Method

Total of 1,099 clean-catch mid stream urine (CCMSU) was processed by standard microbiological technique; 182 were from the diabetic group and 917 nondiabetic. Following identification, all isolates were subjected to antibiotic susceptibility testing using modified Kirby-Bauer disc diffusion method. In-vitro biofilm forming capacity of the isolates were detected by Microtitre plate method. The data were analyzed using SPSS software 16.

Result

Urinary tract infection was found to be significantly higher in diabetic patients (42.9%) compared to nondiabetic patients (17.4%) with Escherichia coli as the most common uropathogen in both diabetic and nondiabetic groups. Similarly, UTI was more common in elderly population (29.5%). Imipenem, nitrofurantoin and amikacin were found to be the most effective drug for uropathogenic E. coli in both diabetic and nondiabetic patients, whereas amoxicillin, ciprofloxacin, and cotrimoxazole were least effective. Of the total bacterial isolates, 43.3% showed positive results for in-vitro biofilm production by the Microtitre plate method. A significantly higher resistance rate was observed among biofilm producing E. coli for quinolones, cotrimoxazole, and third generation cephalosporin ceftriaxone. Most of the biofilm producers (79.5%) were found to be MDR (p-value 0.015).

Conclusion

Elderly populations with diabetes are at a higher risk of UTI. Higher biofilm production and resistance to in-use antimicrobial agents in this study render its inefficacy for empirical treatment and point out the importance of biofilm screening to ensure the effective management of infection.

Virulence-associated genes and drug susceptibility patterns of uropathogenic Escherichia coli isolated from patients with urinary tract infection

Background: Different Escherichia coli phylogenetic groups, such as A, B1, B2, and D, have four functional groups – adhesins, microcins, toxins, and capsules – which can cause urinary tract infections (UTIs). A phylogenetic group with a high virulence content becomes a worldwide health concern. Resistance to antimicrobial agents increasingly complicates the management of E. coli extraintestinal infections, as a major source of illness, death, and increased health care costs. The aim of this study was to determine the virulence content and the antimicrobial susceptibility pattern of different uropathogenic E. coli (UPEC) phylogenetic groups in Ahvaz, Iran.

Methods: Phylogenetic groups, virulence-associated genes (VAGs), and antimicrobial susceptibility tests were detected by molecular and phenotypic methods in a total of 232 clinically well-characterized E. coli strains, isolated from two collections of patients with hospital-acquired (HA) and community-acquired (CA) UTIs.

Results: Our results revealed that among 232 UPEC strains, the most frequent phylogenetic group was phylogroup D (58%) with the greatest content in virulence factors, including kpsM (23%), neuA (76.3%, capsule), cnf (29.6%, toxin), and Pap (54.8%, adhesin). Phylogroups D and, to a lesser extent, B2 were the most drug-resistant phylogroups. In addition, phylogroup D was responsible for the majority of HA (64.7%) and CA (48.4%) infections.

Conclusion: Among UPEC strains causing UTIs, different phylogroups, through different VAGs, could cause severe infection. Knowledge about the distribution of the four functional groups and VAGs belonging to these phylogroups would significantly help to confine and prevent the development of lethal infection caused by these strains.

Treatment of infections caused by multidrug-resistant Gram-negative bacteria: report of the British Society for Antimicrobial Chemotherapy/Healthcare Infection Society/British Infection Association Joint Working Party

The Working Party makes more than 100 tabulated recommendations in antimicrobial prescribing for the treatment of infections caused by multidrug-resistant (MDR) Gram-negative bacteria (GNB) and suggest further research, and algorithms for hospital and community antimicrobial usage in urinary infection. The international definition of MDR is complex, unsatisfactory and hinders the setting and monitoring of improvement programmes. We give a new definition of multiresistance. The background information on the mechanisms, global spread and UK prevalence of antibiotic prescribing and resistance has been systematically reviewed. The treatment options available in hospitals using intravenous antibiotics and in primary care using oral agents have been reviewed, ending with a consideration of antibiotic stewardship and recommendations. The guidance has been derived from current peer-reviewed publications and expert opinion with open consultation. Methods for systematic review were NICE compliant and in accordance with the SIGN 50 Handbook; critical appraisal was applied using AGREE II. Published guidelines were used as part of the evidence base and to support expert consensus. The guidance includes recommendations for stakeholders (including prescribers) and antibiotic-specific recommendations. The clinical efficacy of different agents is critically reviewed. We found there are very few good-quality comparative randomized clinical trials to support treatment regimens, particularly for licensed older agents. Susceptibility testing of MDR GNB causing infection to guide treatment needs critical enhancements. Meropenem- or imipenem-resistant Enterobacteriaceae should have their carbapenem MICs tested urgently, and any carbapenemase class should be identified: mandatory reporting of these isolates from all anatomical sites and specimens would improve risk assessments. Broth microdilution methods should be adopted for colistin susceptibility testing. Antimicrobial stewardship programmes should be instituted in all care settings, based on resistance rates and audit of compliance with guidelines, but should be augmented by improved surveillance of outcome in Gram-negative bacteraemia, and feedback to prescribers. Local and national surveillance of antibiotic use, resistance and outcomes should be supported and antibiotic prescribing guidelines should be informed by these data. The diagnosis and treatment of both presumptive and confirmed cases of infection by GNB should be improved. This guidance, with infection control to arrest increases in MDR, should be used to improve the outcome of infections with such strains. Anticipated users include medical, scientific, nursing, antimicrobial pharmacy and paramedical staff where they can be adapted for local use.

Entrapment of uropathogenic E. coli cells into ultra-thin sol-gel matrices on gold thin films: A low cost alternative for impedimetric bacteria sensing

Bacterial infections are causing worldwide morbidity and mortality. One way to limit infectious outbreaks and optimize clinical management of infections is through the development of fast and sensitive sensing of bacteria. Most sensing approaches are currently based on immunological detection principles. We report here on an impedimetric sensor to selectively and sensitive detect uropathogenic E. coli cells (E. coli UTI89) using artificial recognition sites. We show here the possibility to imprint the rod-shape structure of E. coli UTI 89 into ultra-thin inorganic silica coatings on gold electrodes in a reproducible manner. A linear range from to 1 × 100 -1 × 104 cfu mL-1 is obtained. With a detection limit for E. coli UTI89 below 1 cfu mL-1 from five blank signals (95% confidence level) and excellent selective binding capabilities, these bacterial cell imprinted electrodes brings us closer to a low cost specific bacterial recognition surfaces.

Clinical features and microbiological characteristics of hospital- and community-onset Escherichia coli bloodstream infection

PURPOSE

Escherichia coli is a leading cause of bloodstream infection (BSI) in hospitals and communities.

METHODOLOGY

We conducted a retrospective study in 2015 to evaluate the clinical features and microbiological characteristics of E. coli BSI acquired in the hospital and community.

RESULTS

A total of 100 patients with E. coli BSI were enrolled, among whom 60 % had hospital-onset (HO) BSI while 40 % had community-onset (CO) BSI. Patients with HO BSI had higher percentages of haematological disorders, immunosuppression conditions, underwent surgery within 2 weeks and had a higher 30-day mortality. The prevalences of multidrug-resistant and extended-spectrum β-lactamase-producing strains were 81 and 60 %, respectively. Resistance percentages to ampicillin, ampicillin-sulbactam, cefazolin, ceftriaxone, ciprofloxacin and levofloxacin were greater than 50 %. Of the 43 different sequence types (STs) identified, ST131 (15.3 %) was the most common. The serum agglutination rate was 52 % in which 13 O and 11 H serogroups were observed. Among the 36 detected virulence factor (VF) genes, IutA (66 %) and traT (61 %) were the most predominant. papA, papC and papEF were different between the CO and HO BSI groups. VF scores were high (mean >7) in the frequently detected ST95, ST1193 and ST131.

CONCLUSION

This study revealed that the clinical features of HO and CO E. coli BSI were different. STs and serotypes showed a great diversity in this region while VF genes of the isolates varied between clones.

Predictors of Symptom Duration and Bacteriuria in Uncomplicated Urinary Tract Infection

OBJECTIVE

To identify baseline predictors of symptom duration after empirical treatment for uncomplicated urinary tract infection (UTI) and significant bacteriuria in a cohort of women treated for UTI.

DESIGN

Prospective single-centre cohort study.

SETTING

Outpatient clinic in Norway.

PATIENTS

From September 2010 to November 2011, 441 women aged 16-55 years with symptoms of uncomplicated UTI were included.

RESULTS

Dipstick findings of leukocyte esterase 1 + (incidence rate ratio (IRR) 1.93, 95% confidence interval (CI) 1.23-3.01, p < 0.01) and microbe resistant to mecillinam treatment (IRR 1.41, 95% CI 1.07-1.89, p = 0.02) predicted longer symptom duration. More pronounced symptoms did not predict longer symptom duration (IRR 1.18, 95% CI 0.94-1.46, p = 0.15) or significant bacteriuria (odds ratio [OR] 1.16, 95% CI 0.72-1.88, p = 0.54). Leukocyte esterase 2 + (OR 2.51, 95% CI 0.92-6.83, p = 0.07) or 3 + (OR 2.40, 95% CI 0.88-6.05, p = 0.09) and nitrite positive urine dipstick test (OR 3.22, 95% CI 1.58-7.01, p = <0.01) were associated with bacteriuria.

CONCLUSION

More pronounced symptoms did not correlate with significant bacteriuria or symptom duration after empirical treatment for acute cystitis. One might reconsider the current practice of treating uncomplicated UTI based on symptoms alone. Key Points Treatment strategies for milder infectious diseases must consider ways of reducing antibiotic consumption to decelerate the increase in antibiotic resistance. Our findings suggest that more emphasis should be put on urine dipstick results and bacteriological findings in the clinical setting. One might reconsider the current practice of treating uncomplicated UTIs based on symptoms alone.

Pharmacokinetics and Pharmacodynamics of Fosfomycin and Its Activity against Extended-Spectrum-β-Lactamase-, Plasmid-Mediated AmpC-, and Carbapenemase-Producing Escherichia coli in a Murine Urinary Tract Infection Model

Fosfomycin has become an attractive treatment alternative for urinary tract infections (UTIs) due to increasing multidrug resistance (MDR) in Escherichia coli. In this study, we evaluated the pharmacokinetic (PK) and pharmacodynamic (PD) indices of fosfomycin and its in vivo activity in an experimental murine model of ascending UTI. Subcutaneous administration of fosfomycin showed that the mean peak plasma concentrations of fosfomycin were 36, 280, and 750 mg/liter following administration of a single dose of 0.75, 7.5, and 30 mg/mouse, respectively, with an elimination half-life of 28 min, and urine peak concentrations of 1,100, 33,400, and 70,000 mg/liter expected to be sustained above 1 mg/liter (MIC of the test strain, NU14) for 5, 8, and 9.5 h, respectively. The optimal PK/PD indices for reducing urine colony counts (number of CFU per milliliter) were determined to be the area under the concentration-time curve/MIC from 0 to 72 h and the maximum concentration/MIC on the basis of the dose-dependent bloodstream PK and the results of an evaluation of six dosing regimens. With a dosing regimen of 15 mg/mouse twice (every 36 h), fosfomycin significantly reduced the number of CFU per milliliter of all susceptible strains in urine, including clinical MDR strains, except for one clinical strain (P = 0.062). Variable degrees of reduction were observed in the bladder and kidneys. No significant reductions in the number of CFU per milliliter were observed with the resistant strains. In conclusion, fosfomycin shows concentration-dependent in vivo activity, and the results suggest that fosfomycin is an effective alternative to carbapenems in treating MDR E. coli in uncomplicated UTIs. The data on the effectiveness of fosfomycin against the MDR isolates along with the results of PK/PD modeling should facilitate the further development of improved recommendations for its clinical use.

Phylogenetic relationships, biofilm formation, motility, antibiotic resistance and extended virulence genotypes among Escherichia coli strains from women with community-onset primitive acute pyelonephritis

The present work set out to search for a virulence repertoire distinctive for Escherichia coli causing primitive acute pyelonephritis (APN). To this end, the virulence potential of 18 E. coli APN strains was genotypically and phenotypically assessed, comparatively with 19 strains causing recurrent cystitis (RC), and 16 clinically not significant (control, CO) strains. Most of the strains belong to phylogenetic group B1 (69.8%; p<0.01), and APN strains showed unique features, which are the presence of phylogroup A, and the absence of phylogroup B2 and non-typeable strains. Overall, the most dominant virulence factor genes (VFGs) were ecpA and fyuA (92.4 and 86.7%, respectively; p<0.05), and the mean number of VFGs was significantly higher in uropathogenic strains. Particularly, papAH and malX were exclusive for uropathogenic strains. APN and RC strains showed a significantly higher prevalence of fyuA, usp, and malX than of CO strains. Compared to RC strains, APN ones showed a higher prevalence of iha, but a lower prevalence of iroN, cnf1, and kpsMT-II. Hierarchical cluster analysis showed a higher proportion of two gene clusters (malX and usp, and fyuA and ecpA) were detected in the APN and RC groups than in CO, whereas iutA and iha clusters were detected more frequently in APN strains. The motility level did not differ among the study-groups and phylogroups considered, although a higher proportion of swarming strains was observed in APN strains. Antibiotic-resistance rates were generally low except for ampicillin (37.7%), and were not associated with specific study- or phylogenetic groups. APN and RC strains produced more biofilm than CO strains. In APN strains, iha was associated with higher biofilm biomass formation, whereas iroN and KpSMT-K1 were associated with a lower amount of biofilm biomass. Further work is needed to grasp the virulence and fitness mechanisms adopted by E. coli causing APN, and hence develop new therapeutic and prophylactic approaches.

Molecular characterisation of uropathogenic Escherichia coli isolates at a tertiary care hospital in South India

Uropathogenic Escherichia coli (UPEC) express a multitude of virulence factors (VFs) to break the inertia of the mucosal barrier of the urinary tract. The aim of the present study was undertaken to characterised the UPEC strains and to correlate carriage of specific virulence markers with different phylogroups and also to correlate these findings with clinical outcome of patients. A total of 156 non-repeated, clinically significant UPEC isolates were studied. Virulent genes were determined by two set of multiplex polymerase chain reaction (PCR). Phylogenetic analysis was performed by triplex PCR methods. Antibiograms and patient's clinical outcomes were collected in a structured pro forma. Of the 156 patients infected by UPEC strains with significant bacterial counts the most common predisposing factors were diabetes (45.5%) followed by carcinoma (7%). On analysis of the VF genes of the isolates, a majority of strains (140; 90%) were possessing the fimH gene followed by iutA (98; 63%), papC (76; 49%), cnf1 (46; 29.5%), hlyA (45; 29%) and neuC (8; 5%), respectively. On phylogenetic analysis, 27 (17%) isolates were belong to phylogroup A, 16 (10%) strains to Group B1, 59 (38%) were from Group B2 and 54 (35%) were from Group D. High prevalence of antibiotic resistance was observed among the isolates. The incidence of papC, cnf1 and hlyA was significantly higher (P < 0.05) among the isolates from relapse patients. Our findings indicate that virulent as well as commensal strains are capable of causing urinary tract infection. Virulence genes as well as patients-related factors are equally responsible for the development of infections and also that virulence genes may help such isolates to persist even with appropriate chemotherapy and be responsible for recurrent infections.