fimH Gene Research Articles

Features of urinary Escherichia coli isolated from children with complicated and uncomplicated urinary tract infections in Mexico.

The Hospital Infantil de México Federico Gómez (HIMFG) is a tertiary care hospital in Mexico City where Escherichia coli is frequently isolated from the urine samples of pediatric patients with urinary tract infections. A collection of 178 urinary Escherichia coli (UEc) isolates associated with complicated and uncomplicated urinary tract infections were evaluated in this study. The patterns of resistance to 9 antibiotic classes showed that 60.7% of the UEc isolates had a highly multidrug-resistant (MDR) profile. Genetic diversity analyses of the UEc isolates showed a high variability and revealed 16 clusters associated with four phylogenetic groups, namely, groups A, B1, B2, and D. Phylogenetic group B2 was widely associated with the 16 clusters as well as with virulence and fitness genes. The virulence and fitness genes in the UEc isolates, which included fimbriae-, siderophore-, toxin-, and mobility-associated genes, were grouped as occurring at a low, variable, or high frequency. Interestingly, only the papF gene could be amplified from some UEc isolates, and the sequence analysis of the pap operon identified an insertion sequence (IS) element and gene loss. These data suggested pathoadaptability and the development of immune system evasion, which was confirmed by the loss of P fimbriae-associated agglutination in the UEc isolates. E. coli clone O25-ST131 had a prevalence of 20.2% among the UEc isolates; these isolates displayed both a highly MDR profile and the presence of the papGII, fimH, papGIII, iutD, sat, hlyA, and motA genes. In conclusion, the UEc isolates from complicated urinary tract infection (cUTI) were characterized as being MDR, highly genetically diverse, and associated with phylogenetic group B2 and many virulence and fitness genes. Additionally, gene loss and IS elements were identified in some UEc isolates identified as clone O25-ST131.

Frequency of fimH, magA and rmpA Genes among Klebsiella pneumoniae Isolates in Hospitalized Patients in Babol, Iran

Frequency of fimH, magA and rmpA Genes among Klebsiella pneumoniae Isolates in Hospitalized Patients in Babol, Iran

Adhesion of Salmonella to Pancreatic Secretory Granule Membrane Major Glycoprotein GP2 of Human and Porcine Origin Depends on FimH Sequence Variation.

Bacterial host tropism is a primary determinant of the range of host organisms they can infect. Salmonella serotypes are differentiated into host-restricted and host-adapted specialists, and host-unrestricted generalists. In order to elucidate the underlying molecular mechanisms of host specificity in Salmonella infection, we investigated the role of the intestinal host cell receptor zymogen granule membrane glycoprotein 2 (GP2), which is recognized by FimH adhesin of type 1 fimbriae found in Enterobacteriaceae. We compared four human and two porcine GP2 isoforms. Isoforms were expressed in Sf9 cells as well as in one human (HEp-2) and one porcine (IPEC-J2) cell line. FimH genes of 128 Salmonella isolates were sequenced and the 10 identified FimH variants were compared regarding adhesion (static adhesion assay) and infection (cell line assay) using an isogenic model. We expressed and characterized two functional porcine GP2 isoforms differing in their amino acid sequence to human isoforms by approximately 25%. By comparing all isoforms in the static adhesion assay, FimH variants were assigned to high, low or no-binding phenotypes. This FimH variant-dependent binding was neither specific for one GP2 isoform nor for GP2 in general. However, cell line infection assays revealed fundamental differences: using HEp-2 cells, infection was also FimH variant-specific but mainly independent of human GP2. In contrast, this FimH variant dependency was not obvious using IPEC-J2 cells. Here, we propose an alternative GP2 adhesion/infection mechanism whereby porcine GP2 is not a receptor that determined host-specificity of Salmonella. Salmonella specialists as well as generalists demonstrated similar binding to GP2. Future studies should focus on spatial distribution of GP2 isoforms in the human and porcine intestine, especially comparing health and disease.

Polyphyletic Nature of Salmonella enterica Serotype Derby and Lineage-Specific Host-Association Revealed by Genome-Wide Analysis.

In France, Salmonella Derby is one of the most prevalent serotypes in pork and poultry meat. Since 2006, it has ranked among the 10 most frequent Salmonella serotypes isolated in humans. In previous publications, Salmonella Derby isolates have been characterized by pulsed field gel electrophoresis (PFGE) and antimicrobial resistance (AMR) profiles revealing the existence of different pulsotypes and AMR phenotypic groups. However, these results suffer from the low discriminatory power of these typing methods. In the present study, we built a collection of 140 strains of S. Derby collected in France from 2014 to 2015 representative of the pork and poultry food sectors. The whole collection was characterized using whole genome sequencing (WGS), providing a significant contribution to the knowledge of this underrepresented serotype, with few genomes available in public databases. The genetic diversity of the S. Derby strains was analyzed by single-nucleotide polymorphism (SNP). We also investigated AMR by both genome and phenotype, the main Salmonella pathogenicity island (SPI) and the fimH gene sequences. Our results show that this S. Derby collection is spread across four different lineages genetically distant by an average of 15k SNPs. These lineages correspond to four multilocus sequence typing (MLST) types (ST39, ST40, ST71, and ST682), which were found to be associated with specific animal hosts: pork and poultry. While the ST71 and ST682 strains are pansusceptible, ST40 isolates are characterized by the multidrug resistant profile STR-SSS-TET. Considering virulence determinants, only ST39 and ST40 present the SPI-23, which has previously been associated with pork enterocyte invasion. Furthermore, the pork ST682 isolates were found to carry mutations in the fimH sequence that could participate in the host tropism of this group. Our phylogenetic analysis demonstrates the polyphyletic nature of the Salmonella serotype Derby and provides an opportunity to identify genetic factors associated with host adaptation and markers for the monitoring of these different lineages within the corresponding animal sectors. The recognition of these four lineages is of primary importance for epidemiological surveillance throughout the food production chains and constitutes the first step toward refining monitoring and preventing dispersal of this pathogen.

DetectionOf genesResponsible for BiofilmsFormedby Klebsiella pneumoniaeandEsherichia coliand their effect on innate immunity

Biofilms as a major virulence factor of bacteria ,therelationship between bacteria persistence in the urinary tract and genes responsible for biofilms production was studied. The aim is to detect the presence,frequency of the,fimA, fimH, mrkA and mrkD, genes and biofilms production in two species isolated from UTI patients and their effect on some innate immunity aspects. Sixty five isolates of E.coli and fifty of K.pneumoniae isolates were collected. All isolates were initially diagnosed as genus Esherichiacoli andKlebsiella pneumonia. Final identification for the isolates was done by Vitek 2 compact system. The ability to form biofilm was carried out by using Tissue culture plate method (TCP).Adhesion average to epithelial cells of E.coli and K.pneumoniae was studied. Detection of genes were done to by using PCR technique . Immunological experiments were done by using bactericidal activity and opsonization factor. UTI infection were more common in female than male. 75% (49/65) females, 25%(16/65) males ofE.coli isolates and 88% (44/50) females,12%(6/50) males of K.pneumoniaeisolates. Patients ages in children between (2 months -18years) in UTI caused by E.coli was 35%(23/65) while in k.pneumoniae was 74%(37/50),Ages between (18 years-50 years) in E.coli was 37%(24/65) while in K.pneumoniae was 18%(9/50) finally,Ages between (50 years-72years) in E.coli was 28%(18/65) while in K.pneumoniae was 8%(4/50).69% of E.coli isolates and 72% of k.pneumoniae isolates were higher biofilm producers. . Adhesion average to epithial cells of E.coli and K.pneumoniae was 42.9% and 44% respectively. Both E.coli and K.pneumoniae showed that 100% 0f the 12 isolate harbored the fimA, fimH, mrkA and mrkD genes. The bactericidal average was higher in E.coli than K.pneumoniae , P- value( 0.01) for mice injected with fimbriae, Opsonization factor was higher in E.coli than K.pneumoniae the P value (0.05) . Conclusion: A strong relationship between biofilms production and presence of genes of different species isolated from same clinical source that has effected on resistance of bacteria to innate immunity.

Frequency of virulence factors in high biofilm formation blaKPC-2 producing Klebsiella pneumoniae strains from hospitals

The aim of this study is to determine the frequency of virulence genes in high biofilm formation blaKPC-2 producing Klebsiella pneumoniae strains collected over a period of two years. A total of 43 non-repetitive high biofilm blaKPC-2 producing isolates were screened from 429 strains. The MIC of carbapenems (imipenem and meropenem) ranged from 4 to 32 μg/ml. The OD595 value of the biofilm ranged from 0.56 to 2.56. The K1, K2, K5, K20, K54, K57 genotypes, MLST and virulence factors, including entB, ybtS, mrkD, fimH, rmpA, allS, iutA, kfu, wcaG, aerobaction, fecIRA, shiF, magA and pagO gene, were determined by PCR. The results showed that, among the 43 isolates, 5 of 43 were K1 type, 25 of 43 were K2 type, 4 strains and 2 strains were K5 and K57 respectively. The MLST results showed that 23/43 strains were ST11, followed by ST433(4/43), ST107(4/43), ST690(4/43), ST304(2/43), ST2058(1/43), ST1(1/43), ST146(1/43), ST914(1/43), ST2636(1/43), ST2637(1/43). As to the virulence factors, all 43 strains carried entB, ybtS and mrkD gene, followed by fimH(38/43), rmpA(14/43), allS(34/43), iutA(27/43), kfu(25/43), wcaG(21/43), aerobaction(16/43), fecIRA(15/43), shiF(10/43), magA(5/43) and pagO(5/43). This study demonstrated that high frequency of virulence factors emerging in high biofim blaKPC-2 producing strains. It also suggested that we should continue to focus on the toxicity variation and it's high time to enhance clinical awareness to the infections causing by Klebsiella pneumoniae.

Virulence properties of uropathogenic Escherichia coli isolated from children with urinary tract infection in Korea.

Urinary tract infections (UTIs) are one of the most common types of bacterial infection in humans in various parts of the world and are caused mainly by uropathogenic Escherichia coli (UPEC). A total of 58 UPEC isolates from urine were characterized by serotyping and pulsed-field gel electrophoresis (PFGE). The majority of the UPEC strains belonged to serogroups O2 and O6. The UPEC strains were grouped under different pulsotypes and majority of them belonged to serogroups O2 and O6. Among the 14 virulence factors considered, 13 were present in various serogroups. The virulence genes fimH and sfa were present in all the isolates while none of the isolates carried lt-1. The strains exhibited 36 different virulence patterns, of which 11, referred to as UP (UPEC pattern) 1 to UP 11 were most common. Antibiotic resistance profiling of the UPEC isolates revealed that the serogroups O2 and O6 contain the highest number of resistant strains. The data from the current study depicting the distribution of UPEC strains among various serogroups and pulsotypes, and the occurrence of virulence genes and antibiotics resistance offer useful information on the epidemiological features of UPEC in Korea for the enhanced surveillance of potential emergence of UPEC.

Detection of virulence factors, phylogroups, serogroups and biofilm formation among CTX-M-1 positive Escherichia coli isolated from patients with pyelonephritis

Objectives: Urinary tract infections are among the most frequent infections caused by Escherichia coli isolates. The aims of this study were determination of antibiotic susceptibility and detection of virulence genes, phylogroups, serogroups and biofilm formation of E. coli isolates from patients with pyelonephritis. Methods: A total of 20 E. coli isolates were isolated from pyelonephritis. The antimicrobial susceptibility test was performed for eleven antibiotic disks. The biofilm formation assay was performed with Microtitre Tissue Plate (MTP) assay. The CTX-M1 gene and virulence genes including fimH, fyuA, traT, iutA, papII, kpsMII, ompT, ibeA, sfa, iroN, iucD, afaC, papI and papIII and also phylogroups and serogroups were detected with specific primers. Results: In the biofilm assay, one isolate produced strong biofilm. Among virulence encoding genes, 19 (95%) isolates amplified the all fimH, fyuA and traT genes, followed by iutA (90%, n=18), papII (75%, n=17), kpsMII (60%, n=12), ompT (55%, n=11), ibeA (30%, n=6), sfa (20%, n=5), and iroN=iucD=afaC=15%, (n=3), but none for papI and papIII. The majority (50%, n=10) of E. coli isolates from pyelonephritis belonged to the phylogroup B2, followed by phylogroups D and A (each equal to 20%, n=4) and B1 (10%, n=2). Seroproups included O25 (20%, n=4), O1 (15%, n=3), O4=O18=O75 (each equal to 10%, n=2), and O2=O12=O15=O16=1 (0.05%). Conclusion: The adhesive virulence factors play a critical role in the pathogenesis of pyelonephritis as their prevalence was high. Continued and vigilant surveillance is necessary to monitor the dissemination of antimicrobial resistance in uropathogens.

Incidence and Characterization of Salmonella Isolated From Poultry Meat and its Products

This study was conducted on some poultry products include breast, thigh, shish tawook, shawarma, nuggets and luncheon ( 35 of each) collected from different supermarkets at El Menofiya Governorates for isolation and identification of Salmonella on XLD agar and S.S agar. The incidence on XLD were11.4% , 14.3%, 11.4%, 11.4%, 14.3% and 8.6% from breast, thigh, nuggets, shish tawook, shawerma and luncheon, respectively agar and the incidence of serologically identified Salmonella serotypes were Salmonella Enteritidis , Salmonella Typhimurium , Salmonella Kentucky and Salmonella Virchow. The incidence of Salmonella on S.S agar were 11.4% , 14.3%, 8.6%, 14.3%,11.4% and 5.7% from breast, thigh, nuggets, shish tawook, shawerma and luncheon, respectively and the incidence of serologically identified Salmonella serotypes were Salmonella Enteritidis , Salmonella molade ,Salmonella Kentucky , Salmonella Typhimurium and Salmonella Heidelberg . PCR results showed that fimH gene detected in Salmonella Molade. while hilA and fimH genes detected in Salmonella Heidlberg. And stn, hilA and fimH genes detected in Salmonella Typhimurium, Salmonella. Enteritidis, Salmonella Kentucky) and Salmonella Virchow.

Classification of Avian Pathogenic Escherichia coli (APEC) and Human Uropathogenic Escherichia coli (UPEC) in Phylogenetic Groups and Association with Pathogenicity In Vivo

Background: Avian pathogenic E. coli (APEC) and uropathogenic E. coli (UPEC) are responsible, respectively, for avian colibacillosis and for 80% of urinary tract infections in humans. E. coli control is difficult due to the absence of a reliable method to differentiate pathogenic and commensal strains. Genetic similarity between APEC and UPEC suggests a common ancestral origin and the capability of potentially pathogenic strains to affect human health. The classification in phylogenetic groups facilitates the identification of pathogenic strains. The objective of this work was to classify APEC and UPEC E. coli strains into phylogenetic groups and to associate it with in vivo pathogenicity.Materials, Methods & Results: 460 APEC and 450 UPEC strains, stored in BHI with glycerol at -80°C, were selected. APEC strains were isolated from cellulitis, respiratory tract and poultry litter of broiler flocks from Southern Brazil. The UPEC strains from urinary tract infection were provided by a hospital in Porto Alegre. After DNA extraction, APEC and UPEC strains were classified into four phylogenetic groups (A, B1, B2 and D) by a multiplex-PCR protocol for the detection of the chuA and yjaA genes and the TspE4.C2 DNA fragment. Phylogenetic groups were associated with pathogenicity indexes (PI), presented on a scale of 0 to 10, which were previously obtained through the inoculation of APEC strains in one-day-old chicks. Phylogenetic groups were also associated with the presence of 38 virulence-associated genes. The multiplex-PCR protocol was able to differentiate 100% of the APEC and UPEC strains in the four phylogenetic groups. The majority of APEC strains were classified into phylogenetic groups D (31.1%) and B2 (24.1%). On the other hand, the majority of UPEC strains were classified into B2 (53.6%). Among APEC strains, five genes (crl, mat, ompA, fimC and fimH) were detected in more than 80% of strains in all groups. Some genes showed a significant association with specific phylogenetic groups. Gene ireA was exclusively to group D, kpsMT II and cvaC to B2 and sat was exclusively to B1. Four genes (ireA, sfa/focCD, ibeA, tsh) were detected in more than 70% of UPEC strains in all phylogenetic groups. Gene iroN1 showed a significant association exclusively to group A, and iucD, papC and irp2 to B1 group. APEC isolated from poultry litter presented significantly lower PIs than those isolated from cellulitis and from birds with respiratory signs. The average PI from B2 group was significantly higher than that of D group. In addition, the PIs of the two groups were significantly higher than those of A and B1.Discussion: The high frequency of UPEC classified as B2 is in agreement with the literature. More virulent strains are usually classified into B2 group and some of them may be classified into D group. On the other hand, the distribution of APEC isolates in phylogenetic groups is characterized by variability and it is usually related to the origin of the isolates, as observed in the study. Since E. coli strains isolated from human and poultry face similar challenges in infection establishment of extraintestinal sites, they may share some virulence genes. In this study, most of the 38 genes presented a high frequency in both APEC and UPEC strains. As the distribution of APEC strains in phylogenetic groups showed a significant association with pathogenicity, multiplex-PCR becomes an important tool for screening the pathogenicity of strains isolated from the poultry production chain.

CRISPRi Induced Suppression of Fimbriae Gene (fimH) of a Uropathogenic Escherichia coli: An Approach to Inhibit Microbial Biofilms.

Urinary tract infection (UTI) is one the common infections caused by the recalcitrant nature of biofilms, developed after the pathogen has adhered to the inner lining of the urinary tract. Although significant research has been made in recent years to control these types of infection, but as of yet, no approach has sufficiently been able to reduce the prevalence of UTIs. The main objective of this study was to prevent UTIs through targeting the fimH gene, which is the major virulent factor responsible for biofilm formation. The novelty of this work lies in the use of CRISPRi, a gene specific editing tool to control such types of infections. Accordingly, the system was designed to target fimH gene, responsible for bacterial adherence and this approach was successfully validated by performing microscopic, biofilm and adherence assays.

Type I fimbriae mediate in vitro adherence of porcine F18ac+ enterotoxigenic Escherichia coli (ETEC)

Type I fimbriae commonly expressed by Escherichia coli mediate initial attachment of bacteria to host epithelial cells. However, the role of type I fimbriae in the adherence of porcine enterotoxigenic E. coli (ETEC) to host receptors is unclear. In this study, we examined the role of type I fimbriae in the adherence and biofilm formation of F18ac+ ETEC by constructing mutant strains with deletion of type I fimbrial major subunit (fimA) or minor subunit (fimH). The data indicated that the isogenic ΔfimA and ΔfimH mutants showed significantly lower adherence to porcine epithelial IPEC-1 and IPEC-J2 cells as compared to the F18ac+ ETEC parent strain. In addition, the adherence of F18ac+ ETEC to both cell lines was blocked by the presence of 0.5% D-mannose in the cell culture medium. In addition, both mutant strains impaired their ability to form biofilm in vitro. Interestingly, the deletion of fimA or fimH genes resulted in remarkable up-regulation of the expression of adhesin involved in diffuse adherence (AIDA-I). These results indicated that type I fimbriae may be required for efficient adherence of F18ac+ ETEC to pig epithelial cells and, perhaps, biofilm formation.

Level of Fimbriation Alters the Adhesion of Escherichia coli Bacteria to Interfaces.

Adhesion of bacteria to interfaces is the first step in pathogenic infection, in biofilm formation, and in bioremediation of oil spills and other pollutants. Bacteria use a variety of surface structures to promote interfacial adhesion, with the level of expression of these structures varying in response to local conditions and environmental signals. Here, we investigated how overexpression of type 1 fimbriae, one such appendage, modifies the ability of Escherichia coli to adhere to solid substrates, via biofilm formation and yeast agglomeration, and to oil/water interfaces, via a microbial adhesion to hydrocarbon assay. A plasmid that enables inducible expression of E. coli MG1655 type 1 fimbriae was transformed into fimbriae-deficient mutant strain MG1655ΔfimA. The level of fimH gene expression in the engineered strain, measured using quantitative real-time PCR, could be tuned by changing the concentration of inducer isopropyl β-d-1-thiogalactopyranoside (IPTG), and was higher than that in strain MG1655. Increasing the degree of fimbriation only slightly modified the surface energy and zeta potential of the bacteria, but enhanced their ability to agglomerate yeast cells and to adhere to solid substrates (as measured by biofilm formation) and to oil/water interfaces. We anticipate that the tunable extent of fimbriation accessible with this engineered strain can be used to investigate how adhesin expression modifies the ability of bacteria to adhere to interfaces and to actively self-assemble there.

Virulence, resistance, and genetic relatedness of Escherichia coli and Klebsiella sp. isolated from mule foals

ABSTRACT Respiratory diseases are common in young horses but little is known about such infections in mule foals. This study aimed to characterize Escherichia coli and Klebsiella sp. isolated from tracheal wash (TW) and fecal samples (FS) of mule foals, with or without cytological evidence of respiratory disease. Strains were analyzed against 13 antimicrobials, for presence of Extended spectrum beta-lactamase (ESBL), and virulence genes. Phylogrouping and Randomic (RAPD)-PCR profiles were used to evaluate their genetic relatedness. E. coli strains from TW and FS showed greatest resistance to tetracycline, while Klebsiella strains were mainly resistant to ampicillin; multidrug resistance and ESBL production were also detected. The blaCTX gene prevailed among the E. coli isolates, while the blaSHV gene was more frequently found in K. pneumoniae. The fimH gene was detected in most of the isolates and multiple virulence factors were identified in three E. coli isolates. Most of the E. coli isolates belonged to the B1 phylogroup, but B2 strains displayed more virulence genes. The RAPD assay revealed genetic diversity among strains and was able to distinguish FS isolates from TW isolates. Knowledge of the bacteria associated with the respiratory tract of mule foals is important in the treatment of sick animals.

Nosocomial, Multidrug-Resistant Klebsiella pneumoniae Strains Isolated from Mexico City Produce Robust Biofilms on Abiotic Surfaces but Not on Human Lung Cells.

Klebsiella pneumoniae (Kpn) strains are a leading cause of hospital-acquired infections, including ventilator-associated pneumonia. Resistance to antibiotics, biofilm formation, and the production of certain fimbriae play an important role in the pathogenesis. We investigated the genetic relatedness, antibiotic resistance, virulence potential, and ability to form biofilms of Kpn strains isolated from hospital-acquired infections (n = 76). Strains were isolated at three major hospitals serving the largest metropolitan urban area in Mexico City, Mexico. Enterobacterial repetitive intergenic consensus (ERIC)-PCR demonstrated that clonal groups predominate in each hospital. Selected strains chosen from clonal groups (n = 47) were multidrug resistant (MDR, 83%), although the majority (∼70%) were susceptible to carbapenems. All strains produced robust biofilms on abiotic surfaces, and ∼90% harbored adhesin genes fimH, mrkA, and ecpA. The ultrastructure of biofilms was further studied by high-resolution confocal microscopy. The average height of Kpn biofilms on abiotic surfaces was ∼40 μm. We then assessed formation of biofilms on human lung cells, as a surrogate of lung infection. While Kpn strains formed robust biofilms on abiotic surfaces, studies on lung cells revealed attachment to human cells but scarce formation of biofilms. Gene expression studies revealed a differential temporal expression of an adhesin (ecpA) and a capsule (galF) gene when biofilms were formed on different substrates. Kpn strains isolated from nosocomial infections in Mexico City are MDR, although the majority are still susceptible to carbapenems and form more robust biofilms on polystyrene in comparison to those formed on human cells.

Association between virulence profile, biofilm formation and phylogenetic groups of Escherichia coli causing urinary tract infection and the commensal gut microbiota: A comparative analysis

Variety of virulence factors are involved in the pathogenicity of Escherichia coli, the common cause of the urinary tract infections (UTIs). The aim of this study was to determine some virulence factors involved in the pathogenicity and the phylogenetic grouping of E. coli from UTIs compared with the E. coli isolates from gut microbiota (fecal flora). The isolates were tested for biofilm formation, haemagglutination, cell surface hydrophobicity (CSH), hemolysin production, phylogenetic grouping and the distribution of 6 known virulence genes. Isolates from UTIs showed a significantly higher prevalence of haemagglutination and hemolysin production compared with fecal flora (P ≤ 0.05), while biofilm formation and cell surface hydrophobicity (CSH) were not significantly different among the groups. Prevalence of virulence genes fimH, kpsMT ll, iutA, sat, hlyA, and cnf1 among all isolates were: 94.5%, 66.95%, 67.8%, 39%, 23.07% and 21.08%, respectively. The genes for hlyA, cnf1, kpsMT ll were found to be higher in UTI isolates compared to fecal flora (P ≤ 0.05). The frequency of the isolates in the phylogenetic groups B2, D, A and B1 were 36.7%, 31.3%, 16.2% and 15.6%, respectively. All the virulence genes except fimH were found to be significantly higher in the isolates of groups B2 and D. The results suggests that certain factors are necessary for the host colonization and infection and they are common in both virulent and non-virulent strains, and that the strains in the groups A and B1 having the lower virulence factors must acquire these factors when the condition is in favor of their dissemination to the urinary tract. In contrast the isolates in the groups B2 and D appeared to be potentially virulent.

Genetic diversity of extraintestinal Escherichia coli strains producers of beta-lactamases TEM, SHV and CTX-M associated with healthcare

There are few reports from Venezuela describing the genetic basis that sustains the pathogenic potential and phylogenetics of Escherichia coli extraintestinal strains isolated in health care units. To establish the genetic diversity of extraintestinal E. coli strains producers of betalactamases TEM, SHV and CTX-M associated with healthcare. We studied a collection of 12 strains of extraintestinal E. coli with diminished sensitivity to broad-spectrum cephalosporins. Antimicrobial susceptibility was determined by minimum inhibitory concentration. We determined the phylogenetic groups, virulence factors and genes encoding antimicrobial resistance using PCR, and clonal characterization by repetitive element palindromic-PCR rep-PCR. All strains showed resistance to cephalosporins and joint resistance to quinolones and aminoglycosides. The phylogenetic distribution showed that the A and B1 groups were the most frequent, followed by D and B2. We found all the virulence factors analyzed in the B2 group, and fimH gene was the most frequent among them. We found blaCTX-M in all strains,with a higher prevalence of blaCTX-M-8; two of these strains showed coproduction of blaCTX-M-9 and were genetically identified as blaCTXM-65 and blaCTX-M-147 by sequencing. The strains under study showed genetic diversity, hosting a variety of virulence genes, as well as antimicrobial resistance with no particular phylogroup prevalence. This is the first report of blaCTX-M alleles in Venezuela and in the world associated to non-genetically related strains isolated in health care units, a situation that deserves attention, as well as the rationalization of antimicrobials use.

Prevalence of Adherent-Invasive Escherichia coli with fimH Gene Isolated from Iranian Patients with Ulcerative Colitis

Background: Ulcerative colitis is a kind of inflammatory bowel disease that is considered as immunological response to commensal bacteria colonizing gut lumen. Adherent-invasive Escherichia coli strains are pathogens responsible for ulcerative colitis disease. These bacteria have special virulence factors, including type 1 fimbriae, which could be involved in inflammatory bowel disease. Objectives: The present study was conducted to determine the prevalence of adherent-invasive E. coli with fimH gene isolated from Iranian patients with ulcerative colitis. Methods: Sixty intestinal biopsy samples of 30 patients with ulcerative colitis and 30 individuals without inflammatory bowel disease were examined. Biopsies from rectum, descending, ascending, terminal ileum, and colon were taken during colonoscopy. Results: All biopsy samples were cultured for isolation of E. coli strains. Using polymerase chain reaction assay, the invasive plasmid antigen H and invasion-association locus genes were detected from both isolated bacteria and tissue specimens to confirm the presence of adherent-invasive E. coli. The frequency of adherent-invasive E. coli with type 1 fimbriae was much higher in patients with ulcerative colitis than control subjects. Among isolated bacteria, type 1 fimbriae of adherent-invasive E. coli were detected in 53.3% and 13.3% of ulcerative colitis patients and control subjects, respectively. In addition, from 60 biopsy samples, type 1 fimbriae were detected in 56.7% of ulcerative colitis patients but in 10% of healthy subjects. Conclusions: Subjects without inflammatory bowel disease had a high rate of E. coli strains than patients with ulcerative colitis via cultivation detection. We found a high rate of type 1 fimbriae of adherent-invasive E. coli in ulcerative colitis patients by polymerase chain reaction assay. It appears that the presence of adherent-invasive E. coli with type 1 fimbriae in the gastrointestinal tract of patients with ulcerative colitis is more likely than previously supposed.

Comparative Study between Community Acquired and Hospital Acquired UTI Caused by E. Coli

Background : Uropathogenic Escherichia coli (UPEC) are the primary causative agent of urinary tract infection (UTIs). The pathogenic potential of E.coli strains depends on the presence of virulence markers, which in turn are associated with the severity of the infection. Objectives: To compare the presence of five virulence genes (fimH, PAI, papG, hlyA, traT), antibiotic susceptibility between community acquired (CA) and hospital acquired (HA) UPEC strains. Methodology : A total of 62 UPEC strains divided into 2 groups, 28 CA and 34 HA were tested for antimicrobial resistance against 15 drugs using the disc diffusion method. Screening and confirmatory tests for extended spectrum β lactamases were done as described by clinical laboratory standard institute (CLSI). Strains were tested for the five virulence genes by multiplex polymerase chain reaction. Results: FimH gene was the most detected one in the 62 UPEC strains followed by PAI, papG, hlyA, traT (33.87%, 27.42%, 20.97%, 11.29%, 6.45% respectively). No statistical difference was found between CA and HA as regard gene detection. A positive correlation was found between detection of one gene (PAI) and CA (p-value<0.001), detection of multiple genes with urinary catheter in HA (p-values was <0.001). Antibiotic resistance to ceftazidime, cefepime, amikacin, ciprofloxacin, levofloxacin, cotrimoxazole and nitrofurantoin were significantly higher in HA than CA (p-values were 0.009, 0.011, 0.035, 0.001, 0.017, 0.025 and 0.002 respectively). ESBL producing strains, MDR and Quinolone resistance were significantly higher in HA than CA (p-values were 0.028, <0.001 and 0.050 respectively). Conclusion : There was no statistical difference between CA and HA as regard the presence of virulence genes. Antibiotic resistance did not correlate with the studied virulence genes.

Biofilm Formation and Antimicrobial Resistance Pattern of Uropathogenic E. Coli : Comparison of Phenotypic and Molecular Methods

Background: Biofilm structure is considered an important virulence factor and is associated with UPEC that is formed within the bladder and act as a reservoir for recurrent or/and persistent infection. Biofilm is formed from multiple adherent colonies surrounded by polysaccharide matrix that protects bacterial pathogens from an innate immune response and have major role in antibiotic resistance. Objectives: to determine biofilm production in UPEC phenotypically and genotypically by detection of the genes responsible for biofilm production (pap, fimH and sfa) and to assess their correlation with multi-drug resistance. Methodology: A total 278 catheterized and non-catheterized urine samples from clinically suspected UTI patients were processed by standard microbiological procedures. One hundred E. coli were isolated and analyzed for the production of biofilm by modified congo-red agar (MCRA) and microtitre plate (MTP) methods. Subsequently, the antimicrobial susceptibility test was performed by Kirby Bauer-disk diffusion method for both the biofilm and non-biofilm-producing E. coli strains. The presence of pap, fimH and sfa virulence genes was examined by conventional multiplex PCR assay. Results: One hundred UPEC were isolated from 278 catheterized and non-catheterized urine samples (35.97 %). A positive biofilm phenotype was detected in 75% and 68% on MCRA and MTP respectively. UPEC isolates in catheter-associated infection produced biofilm by MTP (73.0%) and MCRA (81.1%) methods. E. coli strains forming biofilm had significantly higher resistance to antibiotics than non-biofilm producer strains regarding tetracycline, cefotaxime, ciprofloxacin and amikacin. The frequency of detection of the virulence genes (fimH, Pap and sfa) among biofilm producing UPEC were 89.7 % vs. 81.3 %, 80.9 % vs. 73.3 % and 67.6 % vs. 61. 3 % as detected by MTP vs. MCRA respectively. Conclusion: Biofilm formation was more common in catheterized patients and there was an association between biofilm production and antimicrobial resistance. PCR was more reliable for the detection of biofilm forming UPEC as compared to MCRA and MTP methods. The adhesion gene fimH was the most common among those uropathogenic E. coli strains.