scholarly journals Pathogenic Potential, Genetic Diversity, and Population Structure of Escherichia coli Strains Isolated from a Forest-Dominated Watershed (Comox Lake) in British Columbia, Canada

2014 ◽  
Vol 81 (5) ◽  
pp. 1788-1798 ◽  
Author(s):  
Abhirosh Chandran ◽  
Asit Mazumder
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Population Structure ◽  
Virulence Genes ◽  
Repetitive Element ◽  
Fingerprint Analysis ◽  
Pathogenic Potential ◽  
Content Type ◽  
E Coli ◽  
Heat Stable

ABSTRACTEscherichia coliisolates (n= 658) obtained from drinking water intakes of Comox Lake (2011 to 2013) were screened for the following virulence genes (VGs):stx1andstx2(Shiga toxin-producingE. coli[STEC]),eaeand the adherence factor (EAF) gene (enteropathogenicE. coli[EPEC]), heat-stable (ST) enterotoxin (variants STh and STp) and heat-labile enterotoxin (LT) genes (enterotoxigenicE. coli[ETEC]), andipaH(enteroinvasiveE. coli[EIEC]). The only genes detected wereeaeandstx2, which were carried by 37.69% (n= 248) of the isolates. Onlyeaewas harbored by 26.74% (n= 176) of the isolates, representing potential atypical EPEC strains, while onlystx2was detected in 10.33% (n= 68) of the isolates, indicating potential STEC strains. Moreover, four isolates were positive for both thestx2andeaegenes, representing potential EHEC strains. The prevalence of VGs (eaeorstx2) was significantly (P< 0.0001) higher in the fall season, and multiple genes (eaeplusstx2) were detected only in fall. Repetitive element palindromic PCR (rep-PCR) fingerprint analysis of 658E. coliisolates identified 335 unique fingerprints, with an overall Shannon diversity (H′) index of 3.653. Diversity varied among seasons over the years, with relatively higher diversity during fall. Multivariate analysis of variance (MANOVA) revealed that the majority of the fingerprints showed a tendency to cluster according to year, season, and month. Taken together, the results indicated that the diversity and population structure ofE. colifluctuate on a temporal scale, reflecting the presence of diverse host sources and their behavior over time in the watershed. Furthermore, the occurrence of potentially pathogenicE. colistrains in the drinking water intakes highlights the risk to human health associated with direct and indirect consumption of untreated surface water.

scholarly journals Evaluating the Pathogenic Potential of Environmental Escherichia coli by Using the Caenorhabditis elegans Infection Model

2013 ◽  
Vol 79 (7) ◽  
pp. 2435-2445 ◽  
Author(s):  
Alexandra Merkx-Jacques ◽  
Anja Coors ◽  
Roland Brousseau ◽  
Luke Masson ◽  
Alberto Mazza ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Caenorhabditis Elegans ◽  
Virulence Genes ◽  
Human Health Risk ◽  
Environmental Isolates ◽  
Pathogenic Potential ◽  
Content Type ◽  
E Coli ◽  
C Elegans ◽  
Infection Assay

ABSTRACTThe detection and abundance ofEscherichia coliin water is used to monitor and mandate the quality of drinking and recreational water. Distinguishing commensal waterborneE. coliisolates from those that cause diarrhea or extraintestinal disease in humans is important for quantifying human health risk. A DNA microarray was used to evaluate the distribution of virulence genes in 148E. colienvironmental isolates from a watershed in eastern Ontario, Canada, and in eight clinical isolates. Their pathogenic potential was evaluated withCaenorhabditis elegans, and the concordance between the bioassay result and the pathotype deduced by genotyping was explored. Isolates identified as potentially pathogenic on the basis of their complement of virulence genes were significantly more likely to be pathogenic toC. elegansthan those determined to be potentially nonpathogenic. A number of isolates that were identified as nonpathogenic on the basis of genotyping were pathogenic in the infection assay, suggesting that genotyping did not capture all potentially pathogenic types. The detection of the adhesin-encoding genessfaD,focA, andfocG, which encode adhesins; ofiroN2, which encodes a siderophore receptor; ofpic, which encodes an autotransporter protein; and ofb1432, which encodes a putative transposase, was significantly associated with pathogenicity in the infection assay. Overall,E. coliisolates predicted to be pathogenic on the basis of genotyping were indeed so in theC. elegansinfection assay. Furthermore, the detection ofC. elegans-infective environmental isolates predicted to be nonpathogenic on the basis of genotyping suggests that there are hitherto-unrecognized virulence factors or combinations thereof that are important in the establishment of infection.

scholarly journals Virulence Genes in Expanded-Spectrum-Cephalosporin-Resistant and -Susceptible Escherichia coli Isolates from Treated and Untreated Chickens

2015 ◽  
Vol 60 (3) ◽  
pp. 1874-1877 ◽  
Author(s):  
S. Baron ◽  
S. Delannoy ◽  
S. Bougeard ◽  
E. Larvor ◽  
E. Jouy ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Virulence Factors ◽  
Shiga Toxin ◽  
Virulence Genes ◽  
Phylogenetic Groups ◽  
Content Type ◽  
E Coli ◽  
Heat Stable ◽  
Intestinal Infections

This study investigated antimicrobial resistance, screened for the presence of virulence genes involved in intestinal infections, and determined phylogenetic groups ofEscherichia coliisolates from untreated poultry and poultry treated with ceftiofur, an expanded-spectrum cephalosporin. Results show that none of the 76 isolates appeared to be Shiga toxin-producingE. colior enteropathogenicE. coli. All isolates were negative for the major virulence factors/toxins tested (ehxA,cdt, heat-stable enterotoxin [ST], and heat-labile enterotoxin [LT]). The few virulence genes harbored in isolates generally did not correlate with isolate antimicrobial resistance or treatment status. However, some of the virulence genes were significantly associated with certain phylogenetic groups.

scholarly journals Subtilase Cytotoxin-Coding Genes in Verotoxin-Producing Escherichia coli Strains from Sheep and Goats Differ from Those from Cattle

2011 ◽  
Vol 77 (23) ◽  
pp. 8259-8264 ◽  
Author(s):  
José A. Orden ◽  
Pilar Horcajo ◽  
Ricardo de la Fuente ◽  
José A. Ruiz-Santa-Quiteria ◽  
Gustavo Domínguez-Bernal ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Human Disease ◽  
Virulence Genes ◽  
Small Ruminants ◽  
Human Beings ◽  
Content Type ◽  
Sheep And Goats ◽  
E Coli ◽  
Healthy Cattle ◽  
Subtilase Cytotoxin

ABSTRACTSubtilase cytotoxin (SubAB) from verotoxin (VT)-producingEscherichia coli(VTEC) strains was first described in the 98NK2 strain and has been associated with human disease. However, SubAB has recently been found in two VT-negativeE. colistrains (ED 591 and ED 32). SubAB is encoded by two closely linked, cotranscribed genes (subAandsubB). In this study, we investigated the presence ofsubABgenes in 52 VTEC strains isolated from cattle and 209 strains from small ruminants, using PCR. Most (91.9%) VTEC strains from sheep and goats and 25% of the strains from healthy cattle possessedsubABgenes. The presence ofsubABin a high percentage of the VTEC strains from small ruminants might increase the pathogenicity of these strains for human beings. Some differences in the results of PCRs and in the association with some virulence genes suggested the existence of different variants ofsubAB. We therefore sequenced thesubAgene in 12 strains and showed that thesubAgene in most of thesubAB-positive VTEC strains from cattle was almost identical (about 99%) to that in the 98NK2 strain, while thesubAgene in most of thesubAB-positive VTEC strains from small ruminants was almost identical to that in the ED 591 strain. We propose the termssubAB1to describe the SubAB-coding genes resembling that in the 98NK2 strain andsubAB2to describe those resembling that in the ED 591 strain.

scholarly journals Extraintestinal Pathogenic and Antimicrobial-Resistant Escherichia coli, Including Sequence Type 131 (ST131), from Retail Chicken Breasts in the United States in 2013

2017 ◽  
Vol 83 (6) ◽  
Author(s):  
James R. Johnson ◽  
Stephen B. Porter ◽  
Brian Johnston ◽  
Paul Thuras ◽  
Sarah Clock ◽  
...  
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
Virulence Genes ◽  
Meat Products ◽  
The United States ◽  
Sequence Type ◽  
The Other ◽  
Antibiotic Resistant ◽  
Content Type ◽  
E Coli

ABSTRACT Chicken meat products are hypothesized to be vehicles for transmitting antimicrobial-resistant and extraintestinal pathogenic Escherichia coli (ExPEC) to consumers. To reassess this hypothesis in the current era of heightened concerns about antimicrobial use in food animals, we analyzed 175 chicken-source E. coli isolates from a 2013 Consumer Reports national survey. Isolates were screened by PCR for ExPEC-defining virulence genes. The 25 ExPEC isolates (12% of 175) and a 2:1 randomly selected set of 50 non-ExPEC isolates were assessed for their phylogenetic/clonal backgrounds and virulence genotypes for comparison with their resistance profiles and the claims on the retail packaging label (“organic,” “no antibiotics,” and “natural”). Compared with the findings for non-ExPEC isolates, the group of ExPEC isolates had a higher prevalence of phylogroup B2 isolates (44% versus 4%; P < 0.001) and a lower prevalence of phylogroup A isolates (4% versus 30%; P = 0.001), a higher prevalence of multiple individual virulence genes, higher virulence scores (median, 11 [range, 4 to 16] versus 8 [range, 1 to 14]; P = 0.001), and higher resistance scores (median, 4 [range, 0 to 8] versus 3 [range, 0 to 10]; P < 0.001). All five isolates of sequence type 131 (ST131) were ExPEC (P = 0.003), were as extensively resistant as the other isolates tested, and had higher virulence scores than the other isolates tested (median, 12 [range, 11 to 13] versus 8 [range, 1 to 16]; P = 0.005). Organic labeling predicted lower resistance scores (median, 2 [range, 0 to 3] versus 4 [range, 0 to 10]; P = 0.008) but no difference in ExPEC status or virulence scores. These findings document a persisting reservoir of extensively antimicrobial-resistant ExPEC isolates, including isolates from ST131, in retail chicken products in the United States, suggesting a potential public health threat. IMPORTANCE We found that among Escherichia coli isolates from retail chicken meat products purchased across the United States in 2013 (many of these isolates being extensively antibiotic resistant), a minority had genetic profiles suggesting an ability to cause extraintestinal infections in humans, such as urinary tract infection, implying a risk of foodborne disease. Although isolates from products labeled “organic” were less extensively antibiotic resistant than other isolates, they did not appear to be less virulent. These findings suggest that retail chicken products in the United States, even if they are labeled “organic,” pose a potential health threat to consumers because they are contaminated with extensively antibiotic-resistant and, presumably, virulent E. coli isolates.

scholarly journals Estimating the Prevalence of Potential Enteropathogenic Escherichia coli and Intimin Gene Diversity in a Human Community by Monitoring Sanitary Sewage

2013 ◽  
Vol 80 (1) ◽  
pp. 119-127 ◽  
Author(s):  
Kun Yang ◽  
Eulyn Pagaling ◽  
Tao Yan
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Gene Diversity ◽  
Content Type ◽  
E Coli ◽  
Enteric Diseases ◽  
Detection Frequency ◽  
Alternative Approach ◽  
Prevalent Subtype ◽  
Qpcr Quantification

ABSTRACTPresently, the understanding of bacterial enteric diseases in the community and their virulence factors relies almost exclusively on clinical disease reporting and examination of clinical pathogen isolates. This study aimed to investigate the feasibility of an alternative approach that monitors potential enteropathogenicEscherichia coli(EPEC) and enterohemorrhagicE. coli(EHEC) prevalence and intimin gene (eae) diversity in a community by directly quantifying and characterizing target virulence genes in the sanitary sewage. The quantitative PCR (qPCR) quantification of theeae,stx1, andstx2genes in sanitary sewage samples collected over a 13-month period detectedeaein all 13 monthly sewage samples at significantly higher abundance (93 to 7,240 calibrator cell equivalents [CCE]/100 ml) thanstx1andstx2, which were detected sporadically. The prevalence level of potential EPEC in the sanitary sewage was estimated by calculating the ratio ofeaetouidA, which averaged 1.0% (σ = 0.4%) over the 13-month period. Cloning and sequencing of theeaegene directly from the sewage samples covered the majority of theeaediversity in the sewage and detected 17 uniqueeaealleles belonging to 14 subtypes. Among them,eae-β2 was identified to be the most prevalent subtype in the sewage, with the highest detection frequency in the clone libraries (41.2%) and within the different sampling months (85.7%). Additionally, sewage and environmentalE. coliisolates were also obtained and used to determine the detection frequencies of the virulence genes as well aseaegenetic diversity for comparison.

scholarly journals Extended-Spectrum-β-Lactamase- and Plasmid AmpC-Producing Escherichia coli Causing Community-Onset Bloodstream Infection: Association of Bacterial Clones and Virulence Genes with Septic Shock, Source of Infection, and Recurrence

2020 ◽  
Vol 64 (8) ◽  
Author(s):  
Inga Fröding ◽  
Badrul Hasan ◽  
Isak Sylvin ◽  
Maarten Coorens ◽  
Pontus Nauclér ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Septic Shock ◽  
Prostate Biopsy ◽  
Virulence Genes ◽  
Multivariable Analysis ◽  
Bloodstream Infections ◽  
Content Type ◽  
E Coli ◽  
Extended Spectrum ◽  
Community Onset

ABSTRACT Invasive infections due to extended-spectrum-β-lactamase- and pAmpC-producing Escherichia coli (ESBL/pAmpC-EC) are an important cause of morbidity, often caused by the high-risk clone sequence type (ST131) and isolates classified as extraintestinal pathogenic E. coli (ExPEC). The relative influence of host immunocompetence versus microbiological virulence factors in the acquisition and outcome of bloodstream infections (BSI) is poorly understood. Herein, we used whole-genome sequencing on 278 blood culture isolates of ESBL/pAmpC-EC from 260 patients with community-onset BSI collected from 2012 to 2015 in Stockholm to study the association of virulence genes, sequence types, and antimicrobial resistance with severity of disease, infection source, ESBL/pAmpC-EC BSI low-risk patients, and patients with repeated episodes. ST131 subclade C2 comprised 29% of all patients. Factors associated with septic shock in multivariable analysis were patient host factors (hematologic cancer or transplantation and reduced daily living activity), presence of the E. coli virulence factor iss (increased serum survival), absence of phenotypic multidrug resistance, and absence of the genes pap and hsp. Adhesins, particularly pap, were associated with urinary tract infection (UTI) source, while isolates from post-prostate biopsy sepsis had a low overall number of virulence operons, including adhesins, and commonly belonged to ST131 clades A, B, and subclade C1, ST1193, and ST648. ST131 was associated with recurrent episodes. In conclusion, the most interesting finding is the association of iss with septic shock. Adhesins are important for UTI pathogenesis, while otherwise low-pathogenic isolates from the microbiota can cause post-prostate biopsy sepsis.

scholarly journals Virulence Genes and Molecular Typing of Different Groups of Escherichia coli O157 Strains in Cattle

2009 ◽  
Vol 75 (19) ◽  
pp. 6282-6291 ◽  
Author(s):  
István Tóth ◽  
Herbert Schmidt ◽  
Gábor Kardos ◽  
Zsuzsanna Lancz ◽  
Kristina Creuzburg ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Housekeeping Genes ◽  
Enzyme Analysis ◽  
Virulence Plasmid ◽  
O157 Strain ◽  
Pathogenic Potential ◽  
E Coli ◽  
Strain Collection ◽  
Genes Encoding

ABSTRACT Characterization of an Escherichia coli O157 strain collection (n = 42) derived from healthy Hungarian cattle revealed the existence of diverse pathotypes. Enteropathogenic E. coli (EPEC; eae positive) appeared to be the most frequent pathotype (n = 22 strains), 11 O157 strains were typical enterohemorrhagic E. coli (EHEC; stx and eae positive), and 9 O157 strains were atypical, with none of the key stx and eae virulence genes detected. EHEC and EPEC O157 strains all carried eae-gamma, tir-gamma, tccP, and paa. Other virulence genes located on the pO157 virulence plasmid and different O islands (O island 43 [OI-43] and OI-122), as well as espJ and espM, also characterized the EPEC and EHEC O157 strains with similar frequencies. However, none of these virulence genes were detected by PCR in atypical O157 strains. Interestingly, five of nine atypical O157 strains produced cytolethal distending toxin V (CDT-V) and carried genes encoding long polar fimbriae. Macro-restriction fragment enzyme analysis (pulsed-field gel electrophoresis) revealed that these E. coli O157 strains belong to four main clusters. Multilocus sequence typing analysis revealed that five housekeeping genes were identical in EHEC and EPEC O157 strains but were different in the atypical O157 strains. These results suggest that the Hungarian bovine E. coli O157 strains represent at least two main clones: EHEC/EPEC O157:H7/NM (nonmotile) and atypical CDT-V-producing O157 strains with H antigens different from H7. The CDT-V-producing O157 strains represent a novel genogroup. The pathogenic potential of these strains remains to be elucidated.

scholarly journals Occurrence of Virulence Genes Associated with Diarrheagenic Pathotypes in Escherichia coli Isolates from Surface Water

2012 ◽  
Vol 79 (1) ◽  
pp. 328-335 ◽  
Author(s):  
Jatinder P. S. Sidhu ◽  
Warish Ahmed ◽  
Leonie Hodgers ◽  
Simon Toze
Keyword(s):  
Escherichia Coli ◽  
Health Risks ◽  
High Frequency ◽  
Aquatic Ecosystems ◽  
Virulence Genes ◽  
Storm Water ◽  
Storm Events ◽  
Widespread Occurrence ◽  
Content Type ◽  
E Coli

ABSTRACTEscherichia coliisolates (n= 300) collected from six sites in subtropical Brisbane, Australia, prior to and after storm events were tested for the presence of 11 virulence genes (VGs) specific to diarrheagenic pathotypes. The presence ofeaeA,stx1,stx2, andehxAgenes specific for the enterohemorrhagicE. coli(EHEC) pathotype was detected in 56%, 6%, 10%, and 13% of isolates, respectively. The VGsastA(69%) andaggR(29%), carried by enteroaggregative (EAEC) pathotypes, were frequently detected inE. coliisolates. The enteropathogenicE. coli(EPEC) genebfpwas detected in 24% of isolates. In addition, enteroinvasiveE. coli(EIEC) VGipaHwas also detected in 14% of isolates. During dry periods, isolates belonging to the EAEC pathotype were most commonly detected (23%), followed by EHEC (11%) and EPEC (11%). Conversely, a more uniform prevalence of pathotypes, EPEC (14%), EAEC (12%), EIEC (10%), EHEC (7%), and ETEC (7%), was observed after the storm events. The results of this study highlight the widespread occurrence of potentially diarrheagenic pathotypes in the urban aquatic ecosystems. While the presence of VGs inE. coliisolates alone is insufficient to determine pathogenicity, the presence of diarrheagenicE. colipathotypes in high frequency after the storm events could lead to increased health risks if untreated storm water were to be used for nonpotable purposes and recreational activities.

scholarly journals Genome Signatures of Escherichia coli O157:H7 Isolates from the Bovine Host Reservoir

2011 ◽  
Vol 77 (9) ◽  
pp. 2916-2925 ◽  
Author(s):  
Mark Eppinger ◽  
Mark K. Mammel ◽  
Joseph E. LeClerc ◽  
Jacques Ravel ◽  
Thomas A. Cebula
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Phylogenomic Analysis ◽  
Genotypic Differences ◽  
Pathogenic Potential ◽  
Content Type ◽  
E Coli ◽  
A Genome ◽  
Major Interest ◽  
Host Reservoir

ABSTRACTCattle comprise a main reservoir of Shiga toxin-producingEscherichia coliO157:H7 (STEC). The significant differences in host prevalence, transmissibility, and virulence phenotypes among strains from bovine and human sources are of major interest to the public health community and livestock industry. Genomic analysis revealed divergence into three lineages: lineage I and lineage I/II strains are commonly associated with human disease, while lineage II strains are overrepresented in the asymptomatic bovine host reservoir. Growing evidence suggests that genotypic differences between these lineages, such as polymorphisms in Shiga toxin subtypes and synergistically acting virulence factors, are correlated with phenotypic differences in virulence, host ecology, and epidemiology. To assess the genomic plasticity on a genome-wide scale, we have sequenced the whole genome of strain EC869, a bovine-associatedE. coliO157:H7 isolate. Comparative phylogenomic analysis of this key isolate enabled us to place accurately bovine lineage II strains within the genetically homogenousE. coliO157:H7 clade. Identification of polymorphic loci that are anchored both in the chromosomal backbone and horizontally acquired regions allowed us to associate bovine genotypes with altered virulence phenotypes and host prevalence. This study catalogued numerous novel lineage II-specific genome signatures, some of which appear to be associated intimately with the altered pathogenic potential and niche adaptation within the bovine rumen. The presented extended list of polymorphic markers is valuable in the development of a robust typing system critical for forensic, diagnostic, and epidemiological studies of this emerging human pathogen.

scholarly journals Genomic Diversity and Virulence Profiles of Historical Escherichia coli O157 Strains Isolated from Clinical and Environmental Sources

2014 ◽  
Vol 81 (2) ◽  
pp. 569-577 ◽  
Author(s):  
Lydia V. Rump ◽  
Narjol Gonzalez-Escalona ◽  
Wenting Ju ◽  
Fei Wang ◽  
Guojie Cao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
The United States ◽  
Genomic Diversity ◽  
Severe Illness ◽  
Pathogenic Potential ◽  
Content Type ◽  
E Coli ◽  
Virulence Markers ◽  
Virulence Potential ◽  
Food Borne

ABSTRACTEscherichia coliO157:H7 is, to date, the majorE. coliserotype causing food-borne human disease worldwide. Strains of O157 with other H antigens also have been recovered. We analyzed a collection of historic O157 strains (n= 400) isolated in the late 1980s to early 1990s in the United States. Strains were predominantly serotype O157:H7 (55%), and various O157:non-H7 (41%) serotypes were not previously reported regarding their pathogenic potential. Although lacking Shiga toxin (stx) andeaegenes, serotypes O157:H1, O157:H2, O157:H11, O157:H42, and O157:H43 carried several virulence factors (iha,terD, andhlyA) also found in virulent serotypeE. coliO157:H7. Pulsed-field gel electrophoresis (PFGE) showed the O157 serogroup was diverse, with strains with the same H type clustering together closely. Among non-H7 isolates, serotype O157:H43 was highly prevalent (65%) and carried important enterohemorrhagicE. coli(EHEC) virulence markers (iha,terD,hlyA, andespP). Isolates from two particular H types, H2 and H11, among the most commonly found non-O157 EHEC serotypes (O26:H11, O111:H11, O103:H2/H11, and O45:H2), unexpectedly clustered more closely with O157:H7 than other H types and carried several virulence genes. This suggests an early divergence of the O157 serogroup to clades with different pathogenic potentials. The appearance of important EHEC virulence markers in closely related H types suggests their virulence potential and suggests further monitoring of those serotypes not implicated in severe illness thus far.

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