Virulence factors, antibiotic resistance phenotypes and O-serogroups of Escherichia coli strains isolated from community-acquired urinary tract infection patients in Mexico

Stray Dogs (Mongrels) Are Potent Reservoir of Drug-Resistant Pathogens: A Study in Peri-Urban Areas of Kolkata, India

This study depicts the drug-resistance and phylogenomic characteristics of 365 Escherichia coli (EC) and 76 Klebsiella pneumoniae (KP) isolated from stray dogs (293) in and around Kolkata, India. Initial screening found 59 isolates, including 48 E. coli and 11 KP multidrug resistant, which included 33 extended-spectrum β-lactamase, 41 AmpC β-lactamase and 18 metallo-β-lactamase producers carrying blaNDM-1 (11) and blaNDM-5 (7) genes. Majority of them had the resistant genes such as blaCTX-M (33), blaTEM (18), blaSHV (4), blaOXA (17), blaFOX (2), blaDHA (2), blaCITM (15), blaCMY-2 (13), blaGES (2) and blaVEB (2), qnrS (15), qnrB (3), aac-6'-Ib-cr (14), tetA (26), tetB (14), sul-1 (25), armA (2) and rmtB (6), in addition to adherence genes such as csgA (33), fimA (27), fliC (13), sdiA (33), rcsA (38), and rpoS (39). They also carried plasmid of diverse replicon types of which IncFIA and FIB were the most frequent. Phylogrouping categorized most of the MDR E. coli in phylogroup A (20), B1 (14), and B2 (6). Enterobacteriaceae repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) showed genetic diversity of multidrug resistant isolates irrespective of their origin, resistance, and virulence types, differentiating the EC in five clades (A-E) and KP in four clades (A-D). As these stray dogs, which had no history or scope of previous antimicrobial therapy, were found to have contracted potential antimicrobial resistance pathogens, the role of environment in spread of such pathogens and further possibility of human infections cannot be ruled out.

Phylogenetic analysis, biofilm formation, antimicrobial resistance and relationship between these characteristics in Uropathogenic Escherichia coli

BACKGROUND

In the present study, we examine the prevalence of phylogenetic groups, O-serogroups, adhesin genes, antimicrobial resistance, the level of gene expression associated with biofilm formation, and the presence of extended-spectrum beta-lactamase (ESBL) in UPEC strains isolated from both pediatric and adult patients.

METHODS

In this cross-sectional study, 156 UPEC isolates were collected from UTI patients. ESBL-producing isolates were detected using the double-disc synergy (DDS) method, and biofilm formation was assessed through a microplate assay. The presence of O-serogroups, adhesion factors and resistance genes, including ESBLs and PMQR genes, was detected by PCR, and isolates were categorized into phylogenetic groups using multiplex PCR. Additionally, the quantitative real-time PCR method was also used to determine the expression level of genes related to biofilm.

RESULTS

During the study period, 50.6% (79/156) of the samples were obtained from children, and 49.4% (77/156) were from adults. The highest rate of resistance was to NA (91.7%), while FM (10.9%) had the lowest rate of antibiotic resistance. In addition, 67.9% (106/156) of UPEC isolates were ESBL producers. Most of UPEC isolates belonged to phylogenetic group B2 (37.1%). This study revealed that blaCTX-M and qnrS are widely distributed among UPEC isolates. The mean expression levels of fimA genes were significantly higher in non-biofilm producers than in biofilm producers (p < 0.01).

CONCLUSIONS

The high antibiotic resistance rates in this study highlight the significance of local resistance monitoring and investigating underlying mechanisms. Our findings indicate the dominance of phylogroup B2 and group D as the prevailing phylogenetic groups. Consequently, it is imperative to investigate the epidemiological aspects and characterize UPEC isolates across diverse regions and time frames.

Characterization of uropathogenic E. coli from various geographical locations in India

Objectives

Uropathogenic Escherichia coli (UPEC) is the most common causative agent of urinary tract infection, accounting for more than 80% of cases worldwide. This study presents data on prevalent serotypes, resistance profiles, and colonization-aiding virulence characteristics of UPEC from different geographical regions in India.

Methods

UPEC were serotyped through microtiter plate agglutination. Standard techniques were used to detect various virulence characteristics, i.e., biofilm formation (tissue culture plate method), siderophore production (screened on Chrome Azurol S agar and categorized with Csaky's and Arnow's methods), colicin release (agar overlay technique), gelatin hydrolysis (on gelatinase agar), and cell surface hydrophobicity (salt aggregation method). Antibiotic resistance profiles (against 20 antimicrobial agents) and extended-spectrum beta-lactamase (ESBL) were evaluated according to Clinical and Laboratory Standards Institute guidelines.

Results

UPEC strains exhibited very high drug resistance rates to most of the commonly used antimicrobial agents; the highest resistance rates were observed for ampicillin (63.4%), nalidixic acid (63.4%), and cefotaxime (62.1%). High rates of multi-drug resistance (63.36%), ESBL-production (34.1%), and carbapenem-resistance (25.0%) were detected in UPEC strains from all geographical regions of India. Hydrophobicity (61.2%), biofilm production (62.5%), and siderophore production (67.7%) were the most common virulence characteristics of UPEC isolates. Co-expression of virulence characteristics was common (69.8%) in UPEC strains.

Conclusion

UPEC strains with very high antimicrobial-resistance are in circulation in India, and have diverse serotypes and virulence characteristics.

Virulence-associated genes and antimicrobial resistance patterns in bacteria isolated from pregnant and nonpregnant women with urinary tract infections: the risk of neonatal sepsis

Uropathogenic Escherichia coli (UPEC) is classified as the major causative agent of urinary tract infections (UTIs). UPEC virulence and antibiotic resistance can lead to complications in pregnant women and (or) newborns. Therefore, the aim of this study was to determine the etiological agents of UTIs, as well as to identify genes related to virulence factors in bacteria isolated from pregnant and nonpregnant women. A total of 4506 urine samples were collected from pregnant and nonpregnant women. Urine cultures were performed, and PCR was used to identify phylogroups and virulence-related genes. Antibiotic resistance profiles were determined. The incidence of UTIs was 6.9% (pregnant women, n = 206 and nonpregnant women, n = 57), and UPEC belonging to phylogroup A was the most prevalent. The presence of genes related to capsular protection, adhesins, iron acquisition, and serum protection in UPEC was associated with not being pregnant, while the presence of genes related to adhesins was associated with pregnancy. Bacteria isolated from nonpregnant women were more resistant to antibiotics; 36.5% were multidrug resistant, and 34.9% were extensively drug resistant. Finally, UTIs were associated with neonatal sepsis risk, particularly in pregnant women who underwent cesarean section while having a UTI caused by E. coli. In conclusion, UPEC isolated from nonpregnant women carried more virulence factors than those isolated from pregnant women, and maternal UTIs were associated with neonatal sepsis risk.

Phenotypic and genotypic characteristics of Escherichia coli strains isolated during a longitudinal follow-up study of chronic urinary tract infections

Worldwide, Urinary Tract Infections (UTIs) are an important health problem with many cases reported annually, women being the most affected. UTIs are relevant because they can become a recurrent condition, associated with different factors that contribute to the chronicity of the disease (cUTI). cUTI can be classified as persistent (peUTI) when the causative agent is the same each time the infection occurs or as reinfection (reUTI) when the associated microorganism is different. The purpose of this work was to characterize Escherichia coli isolates obtained in two prospective studies of patients with cUTI, to define which of them corresponded to peUTI and which to reUTI. A total of 394 isolates of E. coli were analyzed by agglutination with specific sera, antimicrobial susceptibility by diffusion disc test, and the phylogroups and presence of genes associated with virulence by PCR assays. Additionally, in some characterized strains adherence, invasiveness, and biofilm formation were analyzed by in vitro assays. The results showed that the peUTI strains belonged mainly to the classical UPEC serogroups (O25, O75, O6), were included in the B2 phylogroup, carried a great number of virulence genes, and were adherent, invasive, and biofilm-forming. Meanwhile, reUTI strains showed great diversity of serogroups, belonged mainly in the A phylogroup, and carried fewer virulence genes. Both peUTI and reUTI strains showed extensively drug-resistant (XDR) and multidrug-resistant (MDR) profiles in the antimicrobial susceptibility test. In conclusion, it appears that peUTIs are caused principally by classical UPEC strains, while reUTIs are caused by strains that appear to be a part of the common E. coli intestinal biota. Moreover, although both peUTI and reUTI strains presented different serotypes and phylogroups, their antimicrobial resistance profile (XDR and MDR) was similar, confirming the importance of regulating prophylactic treatments and seeking alternatives for the treatment and control of cUTI. Finally, it was possible to establish the features of the E. coli strains responsible for peUTI and reUTI which could be helpful to develop a fast diagnostic methodology.

Molecular epidemiology and pathogenomics of extended-spectrum beta-lactamase producing- Escherichia coli and - Klebsiella pneumoniae isolates from bulk tank milk in Tennessee, USA

Introduction

The rise in extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in dairy cattle farms poses a risk to human health as they can spread to humans through the food chain, including raw milk. This study was designed to determine the status, antimicrobial resistance, and pathogenic potential of ESBL-producing -E. coli and -Klebsiella spp. isolates from bulk tank milk (BTM).

Methods

Thirty-three BTM samples were collected from 17 dairy farms and screened for ESBL-E. coli and -Klebsiella spp. on CHROMagar ESBL plates. All isolates were confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and subjected to antimicrobial susceptibility testing and whole genome sequencing (WGS).

Results

Ten presumptive ESBL-producing bacteria, eight E. coli, and two K. pneumoniae were isolated. The prevalence of ESBL-E. coli and -K. pneumoniae in BTM was 21.2% and 6.1%, respectively. ESBL-E. coli were detected in 41.2% of the study farms. Seven of the ESBL-E. coli isolates were multidrug resistant (MDR). The two ESBL-producing K. pneumoniae isolates were resistant to ceftriaxone. Seven ESBL-E. coli strains carry the blaCTX-M gene, and five of them co-harbored blaTEM-1. ESBL-E. coli co-harbored blaCTX-M with other resistance genes, including qnrB19, tet(A), aadA1, aph(3'')-Ib, aph(6)-Id), floR, sul2, and chromosomal mutations (gyrA, gyrB, parC, parE, and pmrB). Most E. coli resistance genes were associated with mobile genetic elements, mainly plasmids. Six sequence types (STs) of E. coli were detected. All ESBL-E. coli were predicted to be pathogenic to humans. Four STs (three ST10 and ST69) were high-risk clones of E. coli. Up to 40 virulence markers were detected in all E. coli isolates. One of the K. pneumoniae was ST867; the other was novel strain. K. pneumoniae isolates carried three types of beta-lactamase genes (blaCTX-M, blaTEM-1 and blaSHV). The novel K. pneumoniae ST also carried a novel IncFII(K) plasmid ST.

Conclusion

Detection of high-risk clones of MDR ESBL-E. coli and ESBL-K. pneumoniae in BTM indicates that raw milk could be a reservoir of potentially zoonotic ESBL-E. coli and -K. pneumoniae.

Uropathogenic Escherichia coli (UPEC)-Associated Urinary Tract Infections: The Molecular Basis for Challenges to Effective Treatment

Urinary tract infections (UTIs) are among the most common bacterial infections, especially among women and older adults, leading to a significant global healthcare cost burden. Uropathogenic Escherichia coli (UPEC) are the most common cause and accounts for the majority of community-acquired UTIs. Infection by UPEC can cause discomfort, polyuria, and fever. More serious clinical consequences can result in urosepsis, kidney damage, and death. UPEC is a highly adaptive pathogen which presents significant treatment challenges rooted in a complex interplay of molecular factors that allow UPEC to evade host defences, persist within the urinary tract, and resist antibiotic therapy. This review discusses these factors, which include the key genes responsible for adhesion, toxin production, and iron acquisition. Additionally, it addresses antibiotic resistance mechanisms, including chromosomal gene mutations, antibiotic deactivating enzymes, drug efflux, and the role of mobile genetic elements in their dissemination. Furthermore, we provide a forward-looking analysis of emerging alternative therapies, such as phage therapy, nano-formulations, and interventions based on nanomaterials, as well as vaccines and strategies for immunomodulation. This review underscores the continued need for research into the molecular basis of pathogenesis and antimicrobial resistance in the treatment of UPEC, as well as the need for clinically guided treatment of UTIs, particularly in light of the rapid spread of multidrug resistance.

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.

Antimicrobial Efficacy of Cinnamon Essential Oil against Avian Pathogenic Escherichia coli from Poultry

Colibacillosis, caused by E. coli, is responsible for economic losses in the poultry industry due to mortality, decreased production, and the cost of antibiotic treatments. Prevention of colibacillosis is based on improved biosecurity measures and the use of the vaccine performed with O78 E. coli strains, which is responsible for most cases of colibacillosis. Recently, there has been increased interest in other infection control methods, such as the use of natural compounds. The aim of this study was to evaluate the antimicrobial efficacy of cinnamon essential oil (CEO) against E. coli strains isolated from poultry. The MIC50 and MIC90 of CEO were determined by testing 117 strains belonging to serogroups O78, O2, O128, O139, isolated from laying hens (91 strains), broilers (10 strains), and turkeys (16 strains). The bacterial strains were tested at cell densities of 108 and 106 CFU/mL. At the cell density of 108 CFU/mL, MIC50 and MIC90 were 0.4 and 0.5 µL/mL for most of the tested strains, while they corresponded to 0.5 µL/mL for all strains isolated from broilers and for strains belonging to serogroup O139. At the cell density of 106 CFU/mL, MIC50 and MIC90 were 0.3 and 0.4 µL/mL, regardless of bird species of origin and for strains belonging to serogroups O78 and O2. In addition, a concentration of 0.04 µL/mL of CEO corresponded both to MIC50 and MIC90 for strains belonging to serogroups O139 and O128. Based on these results, cinnamon essential oil showed an effective antibacterial activity against E. coli strains from poultry and could find field application for the prevention of colibacillosis.

Antimicrobial Resistance Patterns and Risk Factors Associated with ESBL-Producing and MDR Escherichia coli in Hospital and Environmental Settings in Lusaka, Zambia: Implications for One Health, Antimicrobial Stewardship and Surveillance Systems

Antimicrobial resistance (AMR) is a public health problem threatening human, animal, and environmental safety. This study assessed the AMR profiles and risk factors associated with Escherichia coli in hospital and environmental settings in Lusaka, Zambia. This cross-sectional study was conducted from April 2022 to August 2022 using 980 samples collected from clinical and environmental settings. Antimicrobial susceptibility testing was conducted using BD PhoenixTM 100. The data were analysed using SPSS version 26.0. Of the 980 samples, 51% were from environmental sources. Overall, 64.5% of the samples tested positive for E. coli, of which 52.5% were from clinical sources. Additionally, 31.8% were ESBL, of which 70.1% were clinical isolates. Of the 632 isolates, 48.3% were MDR. Most clinical isolates were resistant to ampicillin (83.4%), sulfamethoxazole/trimethoprim (73.8%), and ciprofloxacin (65.7%) while all environmental isolates were resistant to sulfamethoxazole/trimethoprim (100%) and some were resistant to levofloxacin (30.6%). The drivers of MDR in the tested isolates included pus (AOR = 4.6, CI: 1.9-11.3), male sex (AOR = 2.1, CI: 1.2-3.9), and water (AOR = 2.6, CI: 1.2-5.8). This study found that E. coli isolates were resistant to common antibiotics used in humans. The presence of MDR isolates is a public health concern and calls for vigorous infection prevention measures and surveillance to reduce AMR and its burdens.

Genotypic characteristics of Uropathogenic Escherichia coli isolated from complicated urinary tract infection (cUTI) and asymptomatic bacteriuria-a relational analysis

Background

Uropathogenic Escherichia coli (UPEC) is the predominant agent causing various categories of complicated urinary tract infections (cUTI). Although existing data reveals that UPEC harboured numerous virulence determinants to aid its survival in the urinary tract, the reason behind the occurrence of differences in the clinical severity of uninary tract infections (UTI) demonstrated by the UPEC infection is poorly understood. Therefore, the present study aims to determine the distribution of virulence determinants and antimicrobial resistance among different phylogroups of UPEC isolated from various clinical categories of cUTI and asymptomatic bacteriuria (ASB) E. coli isolates. The study will also attempt a relational analysis of the genotypic characteristics of cUTI UPEC and ASB E. coli isolates.

Methods

A total of 141 UPEC isolates from cUTI and 160 ASB E. coli isolates were obtained from Universiti Malaya Medical Centre (UMMC). Phylogrouping and the occurrence of virulence genes were investigated using polymerase chain reaction (PCR). Antimicrobial susceptibility of the isolates to different classes of antibiotics was determined using the Kirby Bauer Disc Diffusion method.

Results

The cUTI isolates were distributed differentially among both Extraintestinal Pathogenic E. coli (ExPEC) and non-ExPEC phylogroups. Phylogroup B2 isolates were observed to possess the highest average aggregative virulence score (7.17), a probable representation of the capability to cause severe disease. Approximately 50% of the cUTI isolates tested in this study were multidrug resistant against common antibiotics used to treat UTI. Analysis of the occurrence of virulence genes among different cUTI categories demonstrated that UPEC isolates of pyelonephritis and urosepsis were highly virulent and had the highest average aggregative virulence scores of 7.80 and 6.89 respectively, compared to other clinical categories. Relational analysis of the occurrence of phylogroups and virulence determinants of UPEC and ASB E. coli isolates showed that 46.1% of UPEC and 34.3% of ASB E. coli from both categories were distributed in phylogroup B2 and had the highest average aggregative virulence score of 7.17 and 5.37, respectively. The data suggest that UPEC isolates which carry virulence genes from all four virulence genes groups studied (adhesions, iron uptake systems, toxins and capsule synthesis) and isolates from phylogroup B2 specifically could predispose to severe UTI involving the upper urinary tract. Therefore, specific analysis of the genotypic characteristics of UPEC could be further explored by incorporating the combination of virulence genes as a prognostic marker for predicting disease severity, in an attempt to propose a more evidence driven treatment decision-making for all UTI patients. This will go a long way in enhancing favourable therapeutic outcomes and reducing the antimicrobial resistance burden among UTI patients.

Uropathogenic Escherichia coli in Mexico, an Overview of Virulence and Resistance Determinants: Systematic Review and Meta-analysis

BACKGROUND

Urinary tract infections (UTI) are one of the most common pathologies in Mexico and the majority are caused by uropathogenic Escherichia coli (UPEC). UPEC possesses virulence and resistance determinants that promote UTI development and affect diagnosis and treatment. This study aims to systematically review published reports of virulence genes, antibiotic resistance, and phylogenetic groups prevalent in clinical isolates of UPEC in the Mexican population.

METHODS

Systematic review with meta-analysis was performed following PRISMA guidelines. Articles in both English and Spanish were included. Total prevalence with a 95% confidence interval of each characteristic was calculated. Heterogeneity between studies and geographical areas was assessed by the Cochran Q test (Q), I-square (I²), and H-square (H²). Egger's test was used for risk of bias in publications and asymmetry evaluations.

RESULTS

Forty-two articles were analyzed. The most prevalent virulence genes were ecp (97.25%; n = 364) and fimH (82.34%; n = 1,422), which are associated with lower UTI, followed by papGII (40.98%; n = 810), fliC (38.87%; n = 319), hlyA (23.55%; n = 1,521), responsible for with upper UTI. More than 78.13% (n = 1,893) of the isolates were classified as multidrug-resistant, with a higher prevalence of resistance to those antibiotics that are implemented in the basic regimen in Mexico. The most frequently reported Extended Spectrum β-Lactamase (ESBL) was CTX-M-1 (55.61%; n = 392), and the predominant phylogroup was B2 (35.94%; n = 1,725).

CONCLUSION

UPEC strains are responsible for a large portion of both lower and upper UTI in Mexico, and their multi-drug resistance drastically reduces the number of therapeutic options available.

Susceptibility and Virulence of Enterobacteriaceae Isolated from Urinary Tract Infections in Benin

Enterobacteriaceae represent one of the main families of Gram-negative bacilli responsible for serious urinary tract infections (UTIs). The present study aimed to define the resistance profile and the virulence of Enterobacteriaceae strains isolated in urinary tract infections in Benin. A total of 390 urine samples were collected from patients with UTIs, and Enterobacteriaceae strains were isolated according to standard microbiology methods. The API 20E gallery was used for biochemical identification. All the isolated strains were subjected to antimicrobial susceptibility testing using the disc diffusion method. Extended-spectrum beta-lactamase (ESBL) production was investigated using a double-disc synergy test (DDST), and biofilm production was quantified using the microplate method. Multiplex PCR was used to detect uro-virulence genes, namely: PapG, IronB, Sfa, iucD, Hly, FocG, Sat, FyuA and Cnf, using commercially designed primers. More than 26% (103/390) of our samples were contaminated by Enterobacteriaceae strains at different levels. Thus, E. coli (31.07%, 32/103), Serratia marcescens (11.65%, 12/103), Klebsiella ornithinolytica (8.74%, 9/103), Serratia fonticola (7.77%, 8/103) and Enterobacter cloacae (6.80%, 7/103) were identified. Among the isolated strains, 39.81% (41/103) were biofilm-forming, while 5.83% (6/103) were ESBL-producing. Isolates were most resistant to erythromycin, cefixime, ceftriaxone and ampicillin (≥90%) followed by ciprofloxacin, gentamycin, doxycycline and levofloxacin (≥50%), and least resistant to imipenem (27.18%). In regard to virulence genes, Sfa was the most detected (28.15%), followed by IronB (22.23%), iucD (21.36%), Cnf (15.53%), PapG (9.71%), FocG (8.74%), Sat (6.79%), FyuA (5.82%) and Hyl (2.91%). These data may help improve the diagnosis of uropathogenic strains of Enterobacteriaceae, but also in designing effective strategies and measures for the prevention and management of severe, recurrent, or complicated urinary tract infections in Benin.

High Virulence and Multidrug Resistance of Escherichia coli Isolated in Periodontal Disease

Periodontal disease is caused by different gram-negative anaerobic bacteria; however, Escherichia coli has also been isolated from periodontitis and its role in periodontitis is less known. This study aimed to determine the variability in virulence genotype, antibiotic resistance phenotype, biofilm formation, phylogroups, and serotypes in different emerging periodontal strains of Escherichia coli, isolated from patients with periodontal disease and healthy controls. E. coli, virulence genes, and phylogroups, were identified by PCR, antibiotic susceptibility by the Kirby-Bauer method, biofilm formation was quantified using polystyrene microtiter plates, and serotypes were determined by serotyping. Although E. coli was not detected in the controls (n = 70), it was isolated in 14.7% (100/678) of the patients. Most of the strains (n = 81/100) were multidrug-resistance. The most frequent adhesion genes among the strains were fimH and iha, toxin genes were usp and hlyA, iron-acquisition genes were fyuA and irp2, and protectin genes were ompT, and KpsMT. Phylogroup B2 and serotype O25:H4 were the most predominant among the strains. These findings suggest that E. coli may be involved in periodontal disease due to its high virulence, multidrug-resistance, and a wide distribution of phylogroups and serotypes.

Prevalence of USP and hlyA Genes and Association with Drug Resistance in Uropathogenic Escherichia coli Isolated from Patients in a Tertiary Hospital from Southeast China

E. coli was cultured from the urine of patients from the tertiary hospital located in Southeast China from 2017 to 2019. The species were identified, drug sensitivity test was performed, and the presence of the virulence genes USP and hlyA was determined. A total of 483 strains of E. coli were isolated, including 132 from patients with urinary tract infection (UTI). The resistance to ciprofloxacin was more common in non-UTI patients, while resistance to gentamycin was significantly higher in the UTI group. In the UTI group, the proportions of isolated bacteria with the virulence USP (40.15%) and hlyA (8.33%) genes were significantly higher than in the non-UTI group (19.60 and 2.56%, respectively). The rate of resistance of E. coli toward levofloxacin in the USP⁺ group was significantly (p<0.05) higher than in the USP- group. Thus, we revealed the differences in the rate of drug resistance and prevalence of USP and hlyA between the UTI and non-UTI groups. Furthermore, the presence of the USP gene was found to be associated with greater resistance to levofloxacin.

Association between Escherichia coli with NotI-restriction resistance and urinary tract infections

BACKGROUND

Escherichia coli is the most common cause of urinary tract infections (UTIs). It is widely accepted that uropathogenic E. coli (UPEC) mainly emerge from the distal gut microbiota. Identification of bacterial characteristics that are able to differentiate UPEC from fecal commensal strains will facilitate the development of novel strategies to detect and monitor the spread of UPEC.

METHODS

Fifty fecal commensal, 83 UTI-associated and 40 biliary tract infection (BTI)-associated E. coli isolates were analyzed. The NotI restriction patterns of chromosomal DNA in the isolates were determined by pulse-field gel electrophoresis. The phylogenetic types and the presence of 9 known virulence genes of each isolate were determined by PCR analyses. Additionally, the susceptibilities of the isolates to antibiotics were revealed. Then the associations of NotI resistance with UTI-associated isolates, phylotypes, and antibiotic resistance were assessed.

RESULTS

NotI resistance was correlated with UTI-associated isolates, compared to the fecal isolates. Consistently, NotI-resistant isolates harbored a greater number of virulence factors and mainly belonged to phylotype B2. Additionally NotI resistance was correlated with chloramphenicol resistance among the bacteria. Among the fecal, UTI-associated and BTI-associated groups, the distribution of NotI-resistant group B2 isolates was correlated with UTI-associated bacteria.

CONCLUSION

NotI resistance alone is a potential marker for distinguishing fecal strains and UPEC, while the combination of NotI resistance and B2 phylogeny is a candidate marker to differentiate UPEC from fecal and other extraintestinal pathogenic E. coli. Additionally, NotI resistance may be valuable for assessing the potential of chloramphenicol resistance of E. coli.

Distribution of Pathogenicity Island Markers and Virulence Factors Genes of Extraintestinal Pathogenic Escherichia coli Isolates

Background: Extraintestinal pathogenic Escherichia coli (ExPEC) can colonize the urinary system with various virulence factors. Escaping from the host defense, can lead to serious infections, such as bacteremia and sepsis. Objectives: This study aimed to investigate the presence of phylogenetic groups, various virulence factor genes, and pathogenicity island (PAI) markers of extraintestinal and commensal E. coli isolates. Methods: Within January 2016 and December 2017, 50 E. coli isolates were isolated from simultaneous blood and urine samples of 25 patients hospitalized in Mersin University Faculty of Medicine, Turkey, and 50 commensal E. coli isolates were isolated from fecal 18 samples of healthy volunteers as the control group was included in the study. Phylogenetic groups, virulence factors genes, and PAI markers were determined by the multiplex polymerase chain reaction method. Results: The majority of ExPEC isolates were observed to be in phylogenetic group B2. All of the commensal E. coli isolates were detected in phylogenetic group A. The most predominant virulence factor gene was traT (80%). The most prevalent PAI marker was PAI IV536 (86%). However, the PAI I536, IJ96, and IIJ96 markers were not detected in any isolates. Only PAI IV536 was detected in commensal E. coli isolates. Conclusions: It was determined that E. coli isolates that cause uropathogenic and bloodstream infections contain a higher frequency of PAI than commensal isolates.

Resistência antimicrobiana em uroculturas de moradores das Zonas Norte e Nordeste de Porto Alegre

Introdução: Infecção urinária é motivo comum de consulta na Atenção Primária, requerendo tratamento empírico. Para a seleção do antimicrobiano, é necessário conhecer o perfil de resistência dos uropatógenos na comunidade. Objetivo: Analisar o perfil de resistência antimicrobiana em uroculturas realizadas em pacientes da Atenção Primária à Saúde do Serviço de Saúde Comunitária do Grupo Hospitalar Conceição, de julho de 2017 a junho de 2019. Métodos: Estudo transversal, observacional e descritivo com uroculturas de pacientes ambulatoriais das Unidades de Saúde do Serviço de Saúde Comunitária do Grupo Hospitalar Conceição, nas Zonas Norte e Nordeste de Porto Alegre, de julho de 2017 a junho de 2019. Os dados das uroculturas foram fornecidos pelo laboratório do Grupo Hospitalar e analisados por meio das proporções, por sexo, micro-organismo e resistência antimicrobiana. Resultados: Encontraram-se 2.000 uroculturas positivas no período, principalmente por Escherichia coli (75,50%), Klebsiella pneumoniae (7,80%), Staphylococcus saprophyticus (4,95%), Enterococcus specie (3,35%) e Proteus mirabilis (2,85%). Entre os antibióticos orais testados, a maior resistência foi para ampicilina (48,95%), seguida por sulfametoxazol+trimetoprima (25,85%), norfloxacino (18,05%), ciprofloxacino (18,00%), amoxicilina+clavulanato (11,05%) e nitrofurantoína (8,60%). Considerando-se apenas E. coli, as resistências foram 47,75% para ampicilina, 29,74% para sulfametoxazol+trimetoprima, 19,74% para norfloxacino e ciprofloxacino, 8,08% para amoxicilina+clavulanato e 1,99% para nitrofurantoína. Conclusões: O perfil de resistência antimicrobiana nas Zonas Norte e Nordeste de Porto Alegre sugere que sejam utilizados para tratamento empírico de infecção do trato urinário nessa localidade nitrofurantoína ou amoxicilina+clavulanato.

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.

Pathogen profile of urinary tract infections in Nephrology Unit

Introduction. Urinary tract infection (UTI) is one of the most common types of infection in both hospitalized and outpatient settings. The etiology is mostly bacterial, and the typical causative agent is uropathogenic Escherichia coli. There is a noticeable increase in drug resistance of pathogenic microorganisms.

The aim of the study was retrospective analyses of etiological agents of UTI and their antibiotic resistance patterns in Nephrology Unit patients.

Material and methods. An infection was diagnosed based on the patient’s symptoms and positive results of urine culture, carried out over 26 months. The clinical material was tested by using the VITEK system, the drug susceptibility of the emerged pathogens was identified.

Results. The most common etiological agents of UTI were Gram-negative rods: Escherichia coli (51.23%), Klebsiella spp. (19.3%) and Proteus spp. (13.68%). The analysis of drug resistance profiles of these pathogens showed a high percentage of strains resistant to broad-spectrum penicillins and fluoroquinolones. At the same time, it seems that E. coli isolates presented the most favorable pattern of drug susceptibility in this comparison.

Conclusions. The alarming tendency of increasing drug resistance among pathogens causing UTIs to antibiotics such as penicillins or fluoroquinolones prompts a careful choice of drugs in empirical therapies. The most appropriate practice in this regard seems to be meticulous control of nosocomial infections and making therapeutic decisions based on the knowledge of local microbiological data.

Molecular Epidemiology of Multidrug-Resistant Uropathogenic Escherichia coli O25b Strains Associated with Complicated Urinary Tract Infection in Children

Background: Uropathogenic Escherichia coli (UPEC) has increased the incidence of urinary tract infection (UTI). It is the cause of more than 80% of community-acquired cystitis cases and more than 70% of uncomplicated acute pyelonephritis cases. Aim: The present study describes the molecular epidemiology of UPEC O25b clinical strains based on their resistance profiles, virulence genes, and genetic diversity. Methods: Resistance profiles were identified using the Kirby–Bauer method, including the phenotypic production of extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs). The UPEC serogroups, phylogenetic groups, virulence genes, and integrons were determined via multiplex PCR. Genetic diversity was established using pulsed-field gel electrophoresis (PFGE), and sequence type (ST) was determined via multilocus sequence typing (MLST). Results: UPEC strains (n = 126) from hospitalized children with complicated UTIs (cUTIs) were identified as O25b, of which 41.27% were multidrug resistant (MDR) and 15.87% were extensively drug resistant (XDR). The O25b strains harbored the fimH (95.23%), csgA (91.26%), papGII (80.95%), chuA (95.23%), iutD (88.09%), satA (84.92%), and intl1 (47.61%) genes. Moreover, 64.28% were producers of ESBLs and had high genetic diversity. ST131 (63.63%) was associated primarily with phylogenetic group B2, and ST69 (100%) was associated primarily with phylogenetic group D. Conclusion: UPEC O25b/ST131 harbors a wide genetic diversity of virulence and resistance genes, which contribute to cUTIs in pediatrics.

Relationship Between Antibiotic Resistance Patterns and O-Serogroups in Uropathogenic Escherichia coli Strains Isolated from Iraqi Patients

Background: The O-antigen is one of the uropathogenic Escherichia coli (UPEC) virulence factors used as a biomarker to classify E. coli strains. Objectives: In this study, the relationship between antibiotic resistance patterns and O-serogroups was investigated in UPEC strains isolated from patients with urinary tract infections (UTIs) in southern Iraq. Methods: A total of 100 UPEC isolates from the urine specimens of patients with UTIs within the age range of 4 months to 78 years in various southern Iraqi hospitals were collected (May 2017 to January 2018) and confirmed using biochemical tests (e.g., Analytical Profile Index 20E). Antibiotic susceptibility tests were performed using the disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines. The multiple polymerase chain reaction technique was applied to investigate the prevalence of O-serogroups. Results: The most frequent serogroups in the E. coli isolates were O8 (27.7%) and O25 (24.4%); however, serogroup O83 was not observed in the samples. Serogroups O75, O6, O16, and O18 had the lowest frequency (1.1%) among the examined isolates. Furthermore, 10% of the isolates did not belong to any of the examined serogroups. The phenotypic tests showed that the highest and the lowest resistance belonged to piperacillin (92%) and imipenem (5%), respectively. Serogroups O4 and O21 showed the highest drug resistance; nevertheless, serogroups O75, O18, and O1 showed the lowest drug resistance. Additionally, 94% of the isolates were resistant to three or more classes of antibiotics. Conclusions: According to the results, UPEC isolates showed high resistance to common antibiotics; however, they were sensitive to imipenem and amikacin. Serogroups O8 and O25 were the most common among UPEC isolates. Moreover, O4 and O21 showed the highest drug resistance. There was a direct relationship between antimicrobial resistance and O-serogroups in UPEC isolates.

Antibiotic Resistance and Virulence Genes of Escherichia coli Isolated from Patients with Urinary Tract Infections After Kidney Transplantation from Deceased Donors

Objective

This study aimed to determine the prevalence of antibiotic resistance and virulence genes of Escherichia coli strains among patients with urinary tract infections (UTIs) after kidney transplantation from deceased donors.

Methods

Between January 2014 and June 2018, 64 patients who received kidney transplants from deceased donors at our institution developed a UTI due to E. coli. Polymerase chain reaction was used to detect virulence genes in E. coli strains. The Kirby–Bauer method was used to evaluate the antibiotic susceptibility pattern of the isolates.

Results

Among the study cohort, 46 (71.9%) UTIs were community-acquired (CA), and 18 (28.1%) were hospital-acquired (HA). The percentages of isolated E. coli strains that showed antibiotic resistance were as follows: 92.2% to ampicillin, 76.6% to cefalotin, 81.3% to carbenicillin, 29.7% to ciprofloxacin, 62.5% to cotrimoxazole, 35.9% to gentamicin, 34.4% to levofloxacin, 28.1% to norfloxacin, 68.8% to pefloxacin, 57.8% to trimethoprim/sulfamethoxazole, and 20.3% to amikacin. HA E. coli showed higher resistance to ciprofloxacin, cotrimoxazole, trimethoprim/sulfamethoxazole and amikacin, compared with CA E. coli (P<0.05). The most prevalent virulence genes among the E. coli strains were fim (64.1%), followed by irp2 (56.3%), iroN (46.9%), pap GII (45.3%), sfa (31.3%), pap (25%), iuc (23.4%), pap GI (15.6%), pap GIII (14.1%), hly (9.4%), and cnf (4.7%). The irp2 and iroN genes were found more frequently in the HA E. coli than in the CA E. coli (P<0.05).

Conclusion

The E. coli strains, especially HA E. coli, isolated from UTI patients after kidney transplantation from deceased donors showed resistance to multiple antibiotics and harbored numerous virulence genes. These findings provide insight for genetic characterizations and epidemiological studies of E. coli strains causing UTIs in patients after kidney transplantation from deceased donors.

Frequency of hlyA, hlyB, hlyC and hlyD genes in uropathogenic Escherichia coli isolated from UTI patients in Shiraz

Background and objectives: One of the most important causes of urinary tract infections (UTI) is Escherichia coli. The infection is mainly due to the uropathogenic strain (UPEC), which has key virulence factors, including hemolysis. In this study, we evaluated the frequency of hlyA, hlyB, hlyC and hlyD genes in UPEC strains isolated from clinical samples from Shiraz city, Iran.

Materials and methods: 130 urine samples with suspected UTI were collected from Shiraz medical centers and cultured on blood agar and EMB media. Colonies were then characterized by biochemical methods. The genomes were extracted and the presence of hemolysis genes was detected by polymerase chain reaction (PCR) using hly gene specific primers and 16S rRNA. Drug resistance was assessed by using 10 antibiotic disks in the disk diffusion method, according to CLSI criteria.

Results: Out of the 130 collected UTI samples, 100 were identified as UPECs. Within isolates, the hlyD gene had the highest frequency – 95% – and hlyC had the lowest, with 23%. The frequencies of hlyA and hlyB genes were calculated as 50% and 43%, respectively. The rates of antibiotic resistance to Azithromycin, Ampicillin, Cefotaxime, Nalidixic Acid, Tetracycline, Trimethoprim-Sulfamethoxazole, Cefepime, Aztreonam, Gentamicin, and Nitrofurantoin were 95%, 86%, 68%, 66%, 65%, 64%, 51%, 46%, 44%, 14%, respectively. 98% of these isolates belonged to the MDR group.

Conclusion: This study shows diversity of hemolysis virulence factor in UPECs and unique UPEC drug resistance that would indicate a high antibiotic use in the general population.

Prospective Study in Children with Complicated Urinary Tract Infection Treated with Autologous Bacterial Lysates

Antimicrobial bacteria resistance is an important problem in children with recurrent urinary tract infections (rUTI), thus it is crucial to search for alternative therapies. Autologous bacterial lysates (ABL) may be a potential treatment for rUTI. Twenty-seven children with rUTI were evaluated for one year, urine and stool cultures were performed, 10 colonies of each culture were selected and those identified as Escherichia coli were characterized by serology. For patients who presented ≥105 UFC/mL, an ABL was manufactured and administered orally (1 mL/day) for a month. Twelve children were monitored for ≥1-year, 218 urine and 11 stool samples were analyzed. E. coli (80.5%) was the main bacteria isolated from urine and feces (72%). E. coli of classical urinary serotypes (UPEC), O25:H4, O75:HNM, and O9:HNM were identified in patients with persistent urinary infection (pUTI). In 54% of patients treated with ABL, the absence of bacteria was observed in urine samples after 3 months of treatment, 42% of these remained without UTI between 10-12 months. It was observed that the use of ABL controlled the infection for almost 1 year in more than 60% of the children. We consider it necessary to develop a polyvalent immunogen for the treatment and control of rUTI.

Waterborne Urinary Tract Infections: Have We Overlooked an Important Source of Exposure?

The presence of intestinal pathogenic Escherichia coli in drinking water is well recognized as a risk for diarrhea. The role of drinking water in extraintestinal infections caused by E. coli-such as urinary tract infections (UTIs)-remains poorly understood. Urinary tract infections are a leading cause of outpatient infections globally, with a lifetime incidence of 50-60% in adult women. We reviewed the scientific literature on the occurrence of uropathogenic E. coli (UPEC) in water supplies to determine whether the waterborne route may be an important, overlooked, source of UPEC. A limited number of studies have assessed whether UPEC isolates are present in drinking water supplies, but no studies have measured whether their presence in water may increase UPEC colonization or the risk of UTIs in humans. Given the prevalence of drinking water supplies contaminated with E. coli across the globe, efforts should be made to characterize UTI-related risks associated with drinking water, as well as other pathways of exposure.

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.

Microbiological profile of urinary tract infections in a tertiary medical facility in Western Mexico: An update

Urinary tract infections (UTIs) are one of the most important issues in modern medicine. In developing countries, the use of antibiotics is a common practice, and due to this, antibiotic resistance has increased. The objective of this research was to update and report on the microbiological profile of urinary tract infections based on the number of positive urine cultures (UCs), resistance, sensitivity, and the prevalence of bacterial strains. The results were obtained from the database of a tertiary medical facility in Western Mexico. The number of positive UCs was 1769 from inpatients and outpatients who were users of medical services in the hospital from January to December of 2017. The most commonly isolated microorganism was E. coli, with 1225 cases, of which 603 (49.2%) were ESBL (Extended-Spectrum Beta-Lactamase-producing bacteria) strains. The resistance rate of nitrofurantoin was 36.6%, and meropenem showed the most promising results with a resistance rate of only 7.1%. Resistances to quinolones and cephalosporins among the isolates investigated were 51%-67%. Based on our results, it is necessary to increase controls and to improve management protocols in order to achieve better medical practices by reducing antibiotic resistance.

Molecular, phylogenetic and antibiotic resistance analysis of enteroaggregative escherichia coli/uropathogenic Escherichia coli hybrid genotypes causing urinary tract infections

Background

Horizontal gene transfer of virulence genes (VGs) from different Escherichia coli pathotypes results in the evolution of hybrid strains. Hybrid genotypes of enteroaggregative E. coli and uropathogenic E. coli (EAEC/UPEC) have been reported in sporadic infections and outbreaks of extraintestinal origin. Yet, their association with routine infections is still underrated.

Materials and Methods

In this study, we analysed 163 isolates of E. coli from cases of urinary tract infection seeking hybrid (EAEC/UPEC) strains. Using multiplex polymerase chain reaction, we investigated VGs (adhesive and toxin genes) of UPEC along with EAEC marker genes (aap and agg R), ast A (toxin genes) and serine protease autotransporters of Enterobacteriaceae, pet (plasmid-encoded toxin) and pic (mucinase gene). Those UPEC strains which had characteristic defining genes of EAEC (agg R/aap or their combination) were considered UPEC/EAEC hybrids.

Results

Molecular predictors of EAEC (aap and aggR) were detected in 20.2% (33/163) of the strains. The pap C was also detected in 36% of the EAEC/UPEC hybrid strains. Phylogenetic analysis revealed that hybrid strains belonged to Group D (60.6%). Nearly 73.8% of UPEC and 75.7% of UPEC/EAEC hybrid strains were multidrug-resistant. Among UPEC isolates, 72.3% and in hybrid UPEC/EAEC, 78.7% isolates were able to produce biofilm.

Conclusions

Our results indicated a closer relationship among EAEC and UPEC, which suggested that some EAEC strains can be potential uropathogens. Ours is a first study documenting the existence of EAEC pathotypes VGs in UPEC strains of nosocomial origin; further studies are required to understand the diarrhoeagenic potential of these hybrids.

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.

Marked virulence and azole resistance in Candida albicans isolated from patients with periodontal disease

Candida albicans is an opportunistic fungus frequently associated with periodontal diseases. The objective of this study was to determine the expression patterns of virulence genes associated with those of azole resistance among the strains of C. albicans isolated from patients with periodontal disease. We isolated 80 strains of C. albicans from patients with periodontal disease enrolled from two dental clinics and their antifungal susceptibilities were evaluated using the disc diffusion method. C. albicans and its virulence genes were identified using PCR. The expressions of the virulence genes of C. albicans were analyzed using real-time PCR post in vitro infection of the cell line A549. The phenotype for resistance against azoles such as ketoconazole and fluconazole was observed in all analyzed strains (n = 80), which coincided with the high frequency of occurrence of the genes CDR1 and MDR1 associated with resistance. The frequencies of detection and expression of the genes HWP1 (47/15), ALS1 (80/66), ALS3 (70/30), LIP1 (78/44), LIP4 (77/65), LIP5 (79/58), LIP6 (79/58), PLB1 (79/65), and PLB2 (80/66) were found to be higher in the strains of C. albicans isolated from patients with moderate periodontitis and different expression patterns associated with those for azole resistance were identified. It could be elucidated that the high expression of virulence markers associated with azole resistance in C. albicans might be contributing to the chronicity of periodontal infections.

Significant association between genes encoding virulence factors with antibiotic resistance and phylogenetic groups in community acquired uropathogenic Escherichia coli isolates

BACKGROUND

Antibiotic resistance is an increasing phenomenon in many bacterial pathogens including uropathogenic Escherichia coli. Hypothetical anti-virulent agents could be a solution, but first clear virulence associated gene-pool of antibiotic resistant isolates have to be determined. The aim of this study is to investigate the significant associations between genes encoding VFs with antibiotic resistance and phylogenetic groups in UPEC isolates.

RESULTS

The majority of 248 UPEC isolates belonged to phylogenetic group B2 (67.3%). The maximum and minimum resistance was attributed to amoxicillin (90.3%) and both fosfomycin and imipenem (1.6%) respectively. 11.3% of isolates were resistant to all antibiotic agents except that of imipenem, nitrofurantoin and fosfomycin. These highly resistant isolates were placed only in group B2 and D. The most prevalent virulence gene was ompA (93.5%). The hlyA was the only virulence gene that was significantly more prevalent in the highly resistant isolates. The ompA, malX and hlyA genes were obviously more abundant in the antibiotic resistant isolates in comparison to susceptible isolates. The papC gene was associated with amoxicillin resistance (p-value = 0.006, odds ratio: 26.00).

CONCLUSIONS

Increased resistance to first line drugs prescribed for UTIs were detected in CA-UPEC isolates in our study.. Minimal resistance was observed against nitrofurantoin, fosfomycin and imipenem. Therefore, they are introduced for application in empirical therapy of UTIs. Fosfomycin may be the most effective antibiotic agent against highly resistant UPEC isolates. The presence of the ompA, malX and hlyA genes were significantly associated with resistance to different antibiotic agents. We assume that the ability of UPEC isolates to upgrade their antibiotic resistance capacity may occurs in compliance with the preliminary existence of specific virulence associated genes. But, more investigation with higher number of bacterial isolates, further virulence associated genes and comparison of gene pools from CA-UPEC isolates with HA-UPEC are proposed to confirm these finding and discovering new aspects of this association.

Virulence gene transcription, phylogroups, and antibiotic resistance of cervico-vaginal pathogenic E. coli in Mexico

The pathogenicity of Escherichia coli strains that cause cervico-vaginal infections (CVI) is due to the presence of several virulence genes. The objective of this study was to define the variability regarding the genotype of antibiotic resistance, the transcription profiles of virulence genes after in vitro infection of the vaginal cell line A431 and the phylogroup composition of a group of cervico-vaginal E. coli strains (CVEC). A total of 200 E. coli strains isolated from Mexican women with CVI from two medical units of the Mexican Institute of Social Security were analysed. E. coli strains and antibiotic resistance genes were identified using conventional polymerase chain reaction (PCR), and phylogroups were identified using multiplex PCR. Virulence gene transcription was measured through reverse-transcriptase real-time PCR after infection of the vaginal cell line A431. The most common antibiotic resistance genes among the CVEC strains were aac(3)II, TEM, dfrA1, sul1, and qnrA. The predominant phylogroup was B2. The genes most frequently transcribed in these strains were fimH, papC, irp2, iroN, kpsMTII, cnf1, and ompT, mainly in CVEC strains isolated from chronic and occasional vaginal infections. The strains showed a large diversity of transcription of the virulence genes phenotype and antibiotic resistance genotype, especially in the strains of phylogroups, B2, A, and D. The strains formed 2 large clusters, which contained several subclusters. The genetic diversity of CVEC strains was high. These strains have a large number of transcription patterns of virulence genes, and one-third of them carry three to seven antibiotic resistance genes.

Treatment Failure in Urinary Tract Infections: A Warning Witness for Virulent Multi-Drug Resistant ESBL- Producing Escherichia coli

Background

Global increase in the prevalence of virulent extended-spectrum beta-lactamase (ESBL)-producing uropathogenic Escherichia coli (UPEC), which is also multi-drug resistant (MDR), leads to increase in severity of urinary tract infections (UTIs), decrease in the efficacy of the first-line antibiotics, and therefore increase in the morbidity and mortality rates.

Methods

We investigated the distribution of ESBL-producing UPEC in 78 E. coli isolates from community-acquired UTI patients in southern Iran. The prevalence of three major ESBL genes, antimicrobial resistance patterns against 15 conventional antibiotic disks, and the presence of 11 important virulence genes that involve in the development and progression of UTIs were evaluated in these isolates.

Results

Of the UPECs, 34.6% were ESBL-positive and 96.3% of the ESBL-producers were MDR. Among the ESBL-producers, 100% harbored bla_CTX-M, 63% harbored bla_SHV, and 11.1% harbored bla_TEM genes. ESBL-producers showed a higher level of resistance to the tested cephalosporins, fluoroquinolones, trimethoprim-sulfamethoxazole, and tetracycline than non-ESBL producers. All isolates were resistant to the tested penicillins. Prevalence of resistance to about two-third of the tested antibiotics was higher than 50% and 93.6% of the isolates were MDR. High prevalence of virulence factors particularly the adhesins (82.1% csgA, 73.1% fimH genes) and siderophore (73.1% sitA gene) was seen in the UPECs. But fortunately in MDR isolates, the virulence score and prevalence of hemagglutinin (tsh), hemolysin toxin (hlyD) and invasin (ibeA) genes were lower than in non-MDR UPECs. Shockingly, among the 15 common antibiotics, only nitrofurantoin (<20% resistance) could be recommended as an appropriate drug for the treatment of UTIs due to our ESBL-producer UPECs.

Conclusion

The alarming level of virulent MDR ESBL-producer E. coli strains in this study necessitates the performing of an antibiotic stewardship program, regional screening of ESBL-producers and their virulence properties to select appropriate antibiotic, or designing new therapeutic methods for UTIs by inactivation of the essential virulence factors of UPECs.

Prevalence of Virulence Genes and Their Association with Antimicrobial Resistance Among Pathogenic E. coli Isolated from Egyptian Patients with Different Clinical Infections

Introduction

Escherichia (E.) coli can cause intestinal and extra-intestinal infections which ranged from mild to life-threatening infections. The severity of infection is a product of many factors including virulence properties and antimicrobial resistance.

Objectives

To determine the antibiotic resistance pattern, the distribution of virulence factors and their association with one another and with some selected resistance genes.

Methods

Virulence properties were analyzed phenotypically while antimicrobial susceptibility was tested by Kirby-Bauer agar disc diffusion method. In addition, 64 E. coli isolates were tested for 6 colicin genes, fimH, hlyA, traT, csgA, crl virulence genes and bla_−CTX-M-15, bla_−oxa-2, and bla_−oxa-10 resistance genes by polymerase chain reaction (PCR).

Results

Extra-intestinal pathogenic E. coli isolated from urine and blood samples represented a battery of virulence factors and resistance genes with a great ability to produce biofilm. Also, a significant association (P<0.05) among most of the tested colicin, virulence and resistance genes was observed. The observed associations indicate the importance and contribution of the tested factors in the establishment and the progress of infection especially with Extra-intestinal E. coli (ExPEC) which is considered a great challenging health problem.

Conclusion

There is a need for studying how to control these factors to decrease the rate and the severity of infections. The relationship between virulence factors and resistance genes is complex and needs more studies that should be specific for each area.

Antimicrobial resistance of Escherichia coli isolated from retail foods in northern Xinjiang, China

To determine antimicrobial resistance, 431 samples of retail foods purchased at different supermarkets in Northern Xinjiang were examined in this study. There were 112 Escherichia coli strains that were isolated, with approximately 26% of the samples contaminated by E. coli. The detection rate of E. coli isolated from pork was the highest (59.6%), followed by mutton (52.6%), retail fresh milk (52.4%), duck (36.4%), beef (35.3%), chicken (33.3%), and ready-to-eat food (12.9%); the E. coli detection rate for fish and vegetables was <11%. The result showed that the 112 isolates were mostly resistant to tetracycline (52%), followed by ampicillin (42%), compound trimethoprim/sulfamethoxazole (37%), amoxicillin (33%), and nalidixic acid (32%), imipenem resistance was not detected. One hundred isolates carried at least one antimicrobial resistance gene. The detection rate of resistance genes of our study was as follows: tetA (38%), tetB (27%), bla OXA (40%), bla TEM (20%), floR (20%), sul1 (16%), sul2 (27%), aad Ala (19%), aadB (11%), strA (28%), and strB (24%); tetC and bla PSE were not detected. Virulence genes fimC, agg, stx2, fimA, fyuA, papA, stx1, and eaeA were found in 52, 34, 21, 19, 6, 3, 2, and 2 isolates, respectively; papC was not detected. There was a statistically significant association between fimC and resistance to ciprofloxacin (p = .001), gentamicin (p = .001), amikacin (p = .001), levofloxacin (p = .001), and streptomycin (p = .001); between fimA and resistance to tetracycline (p = .001), ampicillin (p = .001), compound trimethoprim/sulfamethoxazole (p = .001), and amoxicillin (p = .003); between agg and resistance to gentamicin (p = .001), tetracycline (p = .001), ciprofloxacin (p = .017), and levofloxacin (p = .001); and between stx2 and resistance to ampicillin (p = .001), tetracycline (p = .001), compound trimethoprim/sulfamethoxazole (p = .002), and amoxicillin (p = .015).

Phylogenetic Group/Subgroups Distributions, Virulence Factors, and Antimicrobial Susceptibility of Escherichia coli Strains from Urinary Tract Infections in Hatay

INTRODUCTION

Nosocomial and community acquired urinary tract infections (UTIs) are one of the most encountered infections in the world.

METHODS

This study aimed to determine the antibiotic susceptibility, phylogeny, and virulence genes of 153 Escherichia coli strains isolated from UTIs. Antimicrobial susceptibility of the isolates to different classes of antimicrobials was determined by the VITEK-2 automated system. Presence of virulence genes and phylogenetic groups were investigated by PCR.

RESULTS

Regarding susceptibility to antimicrobials, ampicillin resistance was most abundant (67.3%), followed by amoxicillin-clavulanic acid (50.9%); least abundant was resistance to amikacin (1.3%) and nitrofurantoin (1.3%). Multi drug resistance (MDR) was observed in 34.6% of the isolates, and all isolates were found to be susceptible to imipenem, meropenem and fosfomycine. The majority of the isolates belonged to the phylogenetic group B23 (35.9%), followed by A1 (20.9%), D1 (18.9%), D2 (12.4%), A0 (%5.9), B1 (3.9%) and B2 (1.9%). Among E. coli strains examined, 49% had iucD, 32.7% papE-F, 26.1% papC, 15% cnf2, 11.1% sfa, 7.8% cnf1, 1.3% afaE, 1.3% afaD, 1.3% hlyA, 0.7% f17a-A, 0.7% clpG and 0.7% eaeA genes.

CONCLUSIONS

Our research demonstrated that virulence factors were distributed among different phylogroup/subgroups, which play a role in UTIs pathogenesis in humans. For this reason, complex and detailed studies are required to determine the relationship between virulence factors and specific E. coli strains that cause UTIs in humans.

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.

Effect and Analysis of Bacterial Lysates for the Treatment of Recurrent Urinary Tract Infections in Adults

Urinary tract infection (UTI) is a relevant public health problem, economically and socially affecting the lives of patients. The increase of antimicrobial bacterial resistance significantly hinders the treatment of UTIs, raising the need to search for alternative therapies. Bacterial lysates (BL) obtained from Escherichia coli and other pathogens have been used to treat different infectious diseases with promising results. This work aims to evaluate the effect and composition of an autologous BL for the treatment and control of recurrent UTIs in adults. The results show remission in 70% of the patients within the first three months after the administration of BL, while the infection is maintained under control for 6-12 months. The analysis by liquid chromatography-mass spectrometry (LC-MS) of the BL fractions recognized by the sera of patients shows the presence of cytosolic proteins, fimbriae, OMPs, and LPS. Our study demonstrates that the autologous BL contributed to the treatment and control of recurrent UTIs in adults, and its composition shows that different surface components of E. coli are potential immunogens that could be used to create a polyvalent protective vaccine.

Antibiotic Resistance Among Uropathogenic Escherichia coli

Urinary tract infections (UTIs) belong to the most common community-acquired and nosocomial infections. A main etiological factor of UTIs is uropathogenic Escherichia coli (UPEC). This review describes the current state of knowledge on the resistance of UPEC to antibiotics recommended for the treatment of UTIs based on the available literature data. Nitrofurantoin and fosfomycin are recommended as first-line therapy in the treatment of uncomplicated cystitis, and the resistance to these antimicrobial agents remains low between UPEC. Recently, in many countries, the increasing resistance is observed to trimethoprim-sulfamethoxazole, which is widely used as the first-line antimicrobial in the treatment of uncomplicated UTIs. In European countries, the resistance of UPEC to this antimicrobial agent ranges from 14.6% to 60%. The widespread use of fluoroquinolones (FQs), especially ciprofloxacin, in the outpatients is the cause of a continuous increase in resistance to these drugs. The resistance of UPEC to FQs is significantly higher in developing countries (55.5–85.5%) than in developed countries (5.1–32.0%). Amoxicillin-clavulanic acid is recommended as first line-therapy for pyelonephritis or complicated UTI. Resistance rates of UPEC to amoxicillin-clavulanic acid are regionally variable. In European countries the level of resistance to this antimicrobial ranges from 5.3% (Germany) to 37.6% (France). Increasing rates of UPEC resistance to antimicrobials indicate that careful monitoring of their use for UTI treatment is necessary.

Whole-genome sequence analysis of multidrug-resistant uropathogenic strains of Escherichia coli from Mexico

Background: Escherichia coli is the main bacterium associated with urinary tract infections (UTIs), including cystitis and pyelonephritis. Uropathogenic E. coli (UPEC) harbors numerous genes that encode diverse virulence factors contributing to its pathogenicity. The treatment of UTIs has become complicated due to the natural selection of E. coli strains that are multiresistant to several groups of antibiotics regularly used in clinical settings such as hospitals. Genomic reports of the global composition and distribution of the antibiotic resistance and virulence genes of these pathogenic strains are lacking in the Mexican population.

Purpose and methods: The aim of this study was to globally characterize the genomes of a group of UPEC strains by massive parallel sequencing to determine the prevalence and distribution of virulence and antibiotic resistance genes associated with different serotypes and phylogenetic groups.

Results: The strains exhibited 138-197 virulence genes and 29 antibiotic resistance genes related to antibiotics that are commonly used in clinical practice. 

Conclusions: These findings are relevant to the definition of new strategies for treating urinary tract infections in public hospitals and private practice. To further define the epidemiological distribution and composition of these virulence and antibiotic resistance genes, larger studies are needed.

Genetic diversity and antibiotic susceptibility of uropathogenic Escherichia coli isolates from kidney transplant recipients

Purpose

Uropathogenic Escherichia coli (UPEC) strains are a common cause of transplant rejection, morbidity, and mortality among kidney transplant recipients. The virulence of UPEC strains differs based on their pathogenicity islands (PAIs) and susceptibility to antibiotics. The present study evaluates the clonal relationship and antibiotic susceptibility of UPEC PAI-genotypes among Escherichia coli (E. coli) isolates from kidney transplant patients.

Patients and methods

A total of 115 Escherichia coli (E. coli) isolates were collected from kidney transplant recipients with acute urinary tract infections (UTIs). Isolates were typed based on the presence of PAI-markers, and random amplified polymorphic DNA (RAPD). The disk diffusion method was performed for the antibiotic susceptibility pattern of isolates.

Results

According to the PAI-specific virulence markers, 69 (60%), 21 (18.3%), and 25 (21.7%) isolates were identified as genotypes related to UPEC 536, UPEC J96, and UPEC CFT073 strains, respectively. PAI III536 genotypes were the most prevalent genotype in this study. The findings showed a high-sensitivity to imipenem (93.9%) and nitrofurantoin (91.3%) and a low-sensitivity to trimethoprim/sulfamethoxazole (36.5%). Clonal association and similar antibiotic susceptibility pattern were seen in the PAI-related genotypes.

Conclusion

Due to a similar pattern of antibiotic susceptibility of these clonal groups and increased resistance to some important antibiotics such as trimethoprim/sulfamethoxazole in the treatment of urinary tract infections, especially in kidney transplant patients, the spread of these clones should be considered as a serious concern.

EAST1 toxin: An enigmatic molecule associated with sporadic episodes of diarrhea in humans and animals

EAST1 is produced by a subset of enteroaggregative Escherichia coli strains. This toxin is a 38-amino acid peptide of 4100 Da. It shares 50% homology with the enterotoxic domain of STa and interacts with the same receptor. The mechanism of action of EAST1is proposed to be identical to that of STa eliciting a cGMP increase. EAST1 is associated with diarrheal disease in Man and various animal species including cattle and swine. Nevertheless, as EAST1-positive strains as well as culture supernatants did not provoke unequivocally diarrhea either in animal models or in human volunteers, the role of this toxin in disease is today still debated. This review intent is to examine the role of EAST1 toxin in diarrheal illnesses.

Snapshot of Phylogenetic Groups, Virulence, and Resistance Markers in Escherichia coli Uropathogenic Strains Isolated from Outpatients with Urinary Tract Infections in Bucharest, Romania

BACKGROUND

Urinary tract infections (UTIs) caused by Uropathogenic Escherichia coli (UPEC) are among the most common infections worldwide, including Romania. To the best of our knowledge, this is the first study performed on a significant number of community-acquired (CA) UPEC strains isolated from Romanian outpatients, aiming to evaluate and establish potential correlations among the phylogenetic groups (PG), resistance profiles, and the virulence factors (VF) genes of the CA-UPEC isolates.

MATERIALS/METHODS

The present study was performed on a total of 787 UPEC nonrepetitive isolates consecutively isolated during one month from outpatients with CA-UTIs, visiting one of the biggest laboratories in Bucharest, Romania, receiving patients from all over the country. The strains identification was performed by MALDI TOF and the susceptibility patterns were tested using Microscan according to CLSI guidelines. PCR assays were performed to detect the presence of different VFs (fimH gene encoding for type 1 fimbriae, afaBC for A fimbriae, sfaDE for S fimbriae, KpsMTII for capsule, hlyA for haemolysin A, hlyD for haemolysin D, and cnf-1 for tumor necrosis factor), the phylogenetic groups (PG) A, B1, B2, and D, and the extended spectrum beta-lactamases (ESBLs) genes.

RESULTS

The 787 CA-UPEC strains were isolated predominantly from female patients (90.95%) of >30 years (~74%). The resistance rates were 47.52% for ampicillin, 41.16% for tetracycline, 24.39% for cotrimoxazole, 19.18% for amoxicillin-clavulanic acid, 15.50% for cefazolin, 14.99% for ciprofloxacin, and 14.86% for levofloxacin; 35.19% of the investigated strains were MDR and 9.03% ESBL producers (from which 42.25% were positive for blaCTX-M, 38.02% for blaTEM, and 19.71% for blaSHV). FimH was the most frequent virulence gene (93.90%) followed by hlyD (44.34%); afaBC (38.24%); KpsMTII (32.65%); sfaDE (23.88%); hlyA (12.45%); and cnf-1 (7.75%). The distribution of the analyzed UPEC strains in phylogenetic groups was different for non-MDR and MDR strains. Overall, 35% of the strains belonged to the phylogenetic group B2 (harboring the yjaA gene); 27% to group B1 (confirmed by the presence of the TspE4C2 fragment); 16% to group D; and 22% to group A. The CA-UPEC strains included in PG B1 and PG B2 proved to be the most virulent ones, the number of strains carrying multiple VFs (>3) being significantly larger as compared to strains belonging to PG A and PG D) (p<0,0001). The presence of one or two ESBL genes was significantly associated (p =0.0024) with PGs A and D.

CONCLUSIONS

Our findings showed that the community UPEC strains circulating in Bucharest, Romania, belong predominantly to group B2 and >90% harbored the fimH gene. High MDR resistance rates were observed, as well as extended VF profiles, highlighting the importance of this type of studies for improving the epidemiological surveillance and the therapeutic or prophylactic management of the respective infections, in the context of antibiotic resistance emergence.

A Relationship Between O-Serotype, Antibiotic Susceptibility and Biofilm Formation in Uropathogenic Escherichia coli

Uropathogenic Escherichia coli (UPEC) is a well-known pathogen that has perturbed the medical scenario because of its resistance to diverse therapeutic drugs and its ability to form a biofilm. Different O-serogroups are the prevalent cause of urinary tract infections (UTIs) along with their ability to form a biofilm. The present research aimed to assess antibiotic susceptibility, biofilm formation, and serotyping of UPEC isolates in conjunction with the demographic data. Antibiotic susceptibility was determined using the Kirby-Bauer method and biofilm formation was assessed phenotypically and at the molecular level. Serotyping was performed by multiplex PCR. A significant proportion of the total of 120 UPECs was isolated from women (p < 0.05). Most isolates were resistant to cefotaxime, ceftazidime, and tetracycline, but maintained their sensitivity to imipenem. O₂₅, O₁₅, O₈, and O₇₅ were the most commonly detected serogroups. Moreover, O₂₅, O_15, and O₈ were the highest biofilm-producing serogroups among the UPEC isolates. Serogroups O₇₅ and O₂₁ were significantly associated with diabetic patients and subjects with renal disease, respectively (p < 0.05). Overall, our results show that UTI incidence in women should be a subject of concern. The high prevalence of the O₂₅ serogroup associated with a specific antibiotic profile and a high percentage of biofilm formation suggests a close relation between serogroups and characteristic features of UPEC isolates.

O-serogroups of multi-drug resistant cervicovaginal Escherichia coli harboring a battery of virulence genes

Multi-drug resistant cervicovaginal Escherichia coli (CVEC) infections are a serious health problem. The aim of this study is to determine the patterns of virulence genes, antibiotic resistance and O-serogroups of CVEC isolated in Mexico. Two hundred strains of CVEC were isolated from women attending two Clinics at the Instituto Mexicano del Seguro Social. E. coli O-serogroups and virulence markers were identified by PCR. Antibiotic susceptibility was determined using the Kirby-Bauer disc-diffusion method. Serogroups O25 (50%), O75 (9%) and O15 (7.5%) were the most frequent among the CVEC strains isolated. The frequencies for antibiotic resistance were ampicillin 97%, (n = 194); carbenicillin 93.5%, (n = 187); cefalotin 77%, (n = 154); and nitrofurantoin 71%, (n = 142). The frequency of multiresistant isolates (3-12 drugs) was 197 (98.5%). The most frequent virulence genes found were feoB (91.5%), fimH (89.5%), kpsMT11 (75%), iutA (66%), and iroN (59%). One hundred and four distinct patterns of virulence markers with antibiotic-resistance genes associated with O-serogroups were identified amongst CVEC isolates. In conclusion: most CVEC strains isolated were multiresistant to antibiotics, belonged to three O-serogroups, and possessed a battery of virulence factors. This knowledge may lead to improved guidelines and standards for treating cervicovaginal infections.

Urinary tract infection: Pathogenicity, antibiotic resistance and development of effective vaccines against Uropathogenic Escherichia coli

Urinary tract infections (UTIs) are recognized as one of the most common infectious diseases in the world that can be divided to different types. Uropathogenic Escherichia coli (UPEC) strains are the most prevalent causative agent of UTIs that applied different virulence factors such as fimbriae, capsule, iron scavenger receptors, flagella, toxins, and lipopolysaccharide for their pathogenicity in the urinary tract. Despite the high pathogenicity of UPEC strains, host utilizes different immune systems such as innate and adaptive immunity for eradication of them from the urinary tract. The routine therapy of UTIs is based on the use of antibiotics such as β-lactams, trimethoprim, nitrofurantoin and quinolones in many countries. Unfortunately, the widespread and misuse of these antibiotics resulted in the increasing rate of resistance to them in the societies. Increasing antibiotic resistance and their side effects on human body show the need to develop alternative strategies such as vaccine against UTIs. Developing a vaccine against UTI pathogens will have an important role in reduction the mortality rate as well as reducing economic costs. Different vaccines based on the whole cells (killed or live-attenuated vaccines) and antigens (subunits, toxins and conjugatedvaccines) have been evaluated against UTIs pathogens. Furthermore, other therapeutic strategies such as the use of probiotics and antimicrobial peptides are considered against UTIs. Despite the extensive efforts, limited success has been achieved and more studies are needed to reach an alternative of antibiotics for treatment of UTIs.

Distribution of virulence genes and their association with antimicrobial resistance among uropathogenic Escherichia coli isolates from Iranian patients

BACKGROUND

Urinary tract infections (UTIs) are one of the most frequent diseases encountered by humans worldwide. The presence of multidrug-resistant (MDR) uropathogenic Escherichia coli (UPEC) harboring several virulence factors, is a major risk factor for inpatients. We sought to investigate the rate of antibiotic resistance and virulence-associated genes among the UPECs isolated from an Iranian symptomatic population.

METHODS

A total of 126 isolates from inpatients with UTI from different wards were identified as UPEC using the conventional microbiological tests. After identification of UPECs, all the isolates were subjected to antimicrobial susceptibility test and polymerase chain reaction (PCR) to identify the presence of 9 putative virulence genes and their association with the clinical outcomes or antimicrobial resistance.

RESULTS

The data showed that the highest and the lowest resistance rates were observed against ampicillin (88.9%), and imipenem (0.8%), respectively. However, the frequency of resistance to ciprofloxacin was found to be 55.6%. High prevalence of MDR (77.8%) and extended-spectrum β-lactamase (ESBL) (54.8%) were substantial. PCR results revealed the frequency of virulence genes ranged from 0 to 99.2%. Among 9 evaluated genes, the frequency of 4 genes (fimH, sfa, iutA, and PAI marker) was > 50% among all the screened isolates. The iutA, pap GII, and hlyA genes were more detected in the urosepsis isolates with significantly different frequencies. The different combinations of virulence genes were characterized as urovirulence patterns. The isolates recovered from pyelonephritis, cystitis, and urosepsis cases revealed 27, 22, and 6 virulence patterns, respectively. A significant difference was determined between ESBL production with pap GII, iutA, and PAI marker genes.

CONCLUSIONS

Our study highlighted the MDR UPEC with high heterogeneity of urovirulence genes. Considering the high rate of ciprofloxacin resistance, alternative drugs and monitoring of the susceptibility profile for UPECs are recommended.

An evaluation of multidrug-resistant Escherichia coli isolates in urinary tract infections from Aguascalientes, Mexico: cross-sectional study

BACKGROUND

Uropathogenic Escherichia coli (UPEC) are one of the main bacteria causing urinary tract infections (UTIs). The rates of UPEC with high resistance towards antibiotics and multidrug-resistant bacteria have increased dramatically in recent years and could difficult the treatment.

METHODS

The aim of the study was to determine multidrug-resistant bacteria, antibiotic resistance profile, virulence traits, and genetic background of 110 E. coli isolated from community (79 isolates) and hospital-acquired (31 isolates) urinary tract infections. The plasmid-mediated quinolone resistance genes presence was also investigated. A subset of 18 isolates with a quinolone-resistance phenotype was examined for common virulence genes encoded in diarrheagenic and extra-intestinal pathogenic E. coli by a specific E. coli microarray.

RESULTS

Female children were the group most affected by UTIs, which were mainly community-acquired. Resistance to trimethoprim-sulfamethoxazole, ampicillin, and ampicillin-sulbactam was most prevalent. A frequent occurrence of resistance toward ciprofloxacin (47.3%), levofloxacin (43.6%) and cephalosporins (27.6%) was observed. In addition, 63% of the strains were multidrug-resistant (MDR). Almost all the fluoroquinolone (FQ)-resistant strains showed MDR-phenotype. Isolates from male patients were associated to FQ-resistant and MDR-phenotype. Moreover, hospital-acquired infections were correlated to third generation cephalosporin and nitrofurantoin resistance and the presence of kpsMTII gene. Overall, fimH (71.8%) and fyuA (68.2%), had the highest prevalence as virulence genes among isolates. However, the profile of virulence genes displayed a great diversity, which included the presence of genes related to diarrheagenic E. coli. Out of 110 isolates, 25 isolates (22.7%) were positive to qnrA, 23 (20.9%) to qnrB, 7 (6.4%) to qnrS1, 7 (6.4%) to aac(6')lb-cr, 5 (4.5%) to qnrD, and 1 (0.9%) to qnrC genes. A total of 12.7% of the isolates harbored blaCTX-M genes, with blaCTX-M-15 being the most prevalent.

CONCLUSIONS

Urinary tract infection due to E. coli may be difficult to treat empirically due to high resistance to commonly used antibiotics. Continuous surveillance of multidrug resistant organisms and patterns of drug resistance are needed in order to prevent treatment failure and reduce selective pressure. These findings may help choosing more suitable treatments of UTI patients in this region of Mexico.