scholarly journals Molecular Evolution of Typical Enteropathogenic Escherichia coli: Clonal Analysis by Multilocus Sequence Typing and Virulence Gene Allelic Profiling

2006 ◽  
Vol 189 (2) ◽  
pp. 342-350 ◽  
Author(s):  
David W. Lacher ◽  
Hans Steinsland ◽  
T. Eric Blank ◽  
Michael S. Donnenberg ◽  
Thomas S. Whittam
Keyword(s):  
Escherichia Coli ◽  
Multilocus Sequence Typing ◽  
Fragment Length Polymorphism ◽  
Allelic Variation ◽  
Virulence Gene ◽  
Rflp Analysis ◽  
Infantile Diarrhea ◽  
E Coli ◽  
Typical Epec ◽  
Enterocyte Effacement

ABSTRACT Enteropathogenic Escherichia coli (EPEC) infections are a leading cause of infantile diarrhea in developing nations. Typical EPEC isolates are differentiated from other types of pathogenic E. coli by two distinctive phenotypes, attaching effacement and localized adherence. The genes specifying these phenotypes are found on the locus of enterocyte effacement (LEE) and the EPEC adherence factor (EAF) plasmid. To describe how typical EPEC has evolved, we characterized a diverse collection of strains by multilocus sequence typing (MLST) and performed restriction fragment length polymorphism (RFLP) analysis of three virulence genes (eae, bfpA, and perA) to assess allelic variation. Among 129 strains representing 20 O-serogroups, 21 clonal genotypes were identified using MLST. RFLP analysis resolved nine eae, nine bfpA, and four perA alleles. Each bfpA allele was associated with only one perA allele class, suggesting that recombination has not played a large role in shuffling the bfpA and perA loci between separate EAF plasmids. The distribution of eae alleles among typical EPEC strains is more concordant with the clonal relationships than the distribution of the EAF plasmid types. These results provide further support for the hypothesis that the EPEC pathotype has evolved multiple times within E. coli through separate acquisitions of the LEE island and EAF plasmid.

scholarly journals Molecular Characterization of a Serotype O121:H19 Clone, a Distinct Shiga Toxin-Producing Clone of Pathogenic Escherichia coli

2002 ◽  
Vol 70 (12) ◽  
pp. 6853-6859 ◽  
Author(s):  
Cheryl L. Tarr ◽  
Teresa M. Large ◽  
Chris L. Moeller ◽  
David W. Lacher ◽  
Phillip I. Tarr ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Allelic Variation ◽  
Virulence Gene ◽  
Gene Profiling ◽  
Enzyme Electrophoresis ◽  
Sequencing Analysis ◽  
Chromosomal Dna ◽  
Waterborne Outbreak ◽  
E Coli

ABSTRACT Most illnesses caused by Shiga toxin-producing Escherichia coli (STEC) have been attributed to E. coli serotype O157:H7, but non-O157 STEC infections are now increasingly recognized as public health problems worldwide. The O121:H19 serotype is being isolated more frequently from clinical specimens and has been implicated in one waterborne outbreak. We used multilocus virulence gene profiling, a PCR-based assay, to characterize the virulence gene content of 24 isolates of serotype O121:H19 and nonmotile variants. We also performed multilocus enzyme electrophoresis and multilocus sequencing to establish the clonal relatedness of O121 isolates and to elucidate the relationship of O121 to common STEC clones. The 24 isolates were found to represent a single bacterial clone, as there was no allelic variation across 18 enzyme loci among the isolates. The complete nucleotide sequence of the intimin gene differed by four substitutions from that of the epsilon (Int-ε) allele of O103:H2 strain PMK5. The typical O121 virulence gene profile was similar to the profiles of enterohemorrhagic E. coli (EHEC) clones of E. coli: it included a Shiga toxin 2 gene (stx 2), two genes on the EHEC plasmid (toxB and ehxA), and the gene encoding intimin (eae). Despite the similarities, putative virulence genes distributed on O islands—large chromosomal DNA segments present in the O157:H7 genome—were useful for discriminating among STEC serotypes and the O121:H19 clone had a composite profile that was distinct from the profiles of the other major EHEC clones of pathogenic E. coli. On the basis of sequencing analysis with 13 housekeeping genes, the O121:H19 clone did not fall into any of the four classical EHEC and enteropathogenic E. coli groups but instead was closely related to two eae-negative STEC strains.

Glucose Decreases Virulence Gene Expression of Escherichia coli O157:H7

2012 ◽  
Vol 75 (4) ◽  
pp. 748-752 ◽  
Author(s):  
V. DELCENSERIE ◽  
G. LaPOINTE ◽  
T. CHARASLERTRANGSI ◽  
A. RABALSKI ◽  
M. W. GRIFFITHS
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Quorum Sensing ◽  
Shiga Toxin ◽  
Virulence Gene ◽  
Escherichia Coli O157 ◽  
Virulence Gene Expression ◽  
E Coli ◽  
Reverse Transcription Pcr ◽  
Enterocyte Effacement

Escherichia coli O157:H7 is responsible for a human toxico-infection that can lead to severe complications such as hemolytic uremic syndrome. Inside the intestine, E. coli O157:H7 forms typical attaching-effacing lesions and produces Shiga toxins. The genes that are responsible for these lesions are located in a pathogenicity island called the locus of enterocyte effacement (LEE). LEE gene expression is influenced by quorum sensing through the luxS system. In this study, the effect of glucose on the expression of several genes from LEE, on the expression of Shiga toxin genes, and on the expression of luxS was assessed with real-time, reverse transcription PCR. All concentrations of glucose (from 0.1 to 1%) were able to down-regulate genes from the LEE operon. A slight down-regulation of genes implicated in Shiga toxin expression was also observed but was significant for low doses of glucose (0.1 to 0.5%) only. A slight but significant increase in luxS expression was observed with 1% glucose. This confirms that in addition to quorum sensing, the presence or absence of nutrients such as glucose has an impact on the down- or upregulation of LEE-encoded virulence genes by the bacterium. The influence of glucose on the virulence of E. coli O157:H7 has received little attention, and these results suggest that glucose can have an important effect on the virulence of E. coli O157:H7.

scholarly journals Molecular and phenotypic typing of enteropathogenic Escherichia coli isolated in childhood acute diarrhea in Abuja, Nigeria

2017 ◽  
Vol 11 (07) ◽  
pp. 527-535 ◽  
Author(s):  
Casmir Ifeanyichukwu Cajetan Ifeanyi ◽  
Nkiruka Florence Ikeneche ◽  
Bassey Enya Bassey ◽  
Stefano Morabito ◽  
Caterina Graziani ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acute Diarrhea ◽  
Antimicrobial Agents ◽  
Virulence Gene ◽  
Enteropathogenic Escherichia Coli ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Typical Epec ◽  
Marked Resistance

Introduction: Enteropathogenic Escherichia coli (EPEC) causes infectious diarrhea among children in developing countries. However, in Nigeria, due to limited laboratory resources, the genetic diversity of its virulence factors, which include intimin subtypes, remains undefined. Methodology: EPEC isolates from diarrheic children 60 months of age and younger in Abuja, Nigeria, were analyzed. Polymerase chain reaction (PCR) for EPEC virulence gene, Hep-2 cell adherence, and serotyping were performed. EPEC strains were further subtyped by PCR for the identification of intimin subtype genes α (alpha), β (beta), γ1 (gamma-1), and έ (epsilon). Antibiotic resistance and extended-spectrum beta-lactamase (ESBL) production was determined by Clinical and Laboratory Standards Institute guidelines. Results: Overall, 18 (4.5%) out of 400 children with acute diarrhea had EPEC infection.  Typical EPEC (tEPEC) strains were detected in 14 (3.5%), whereas 4 (1.1%) were atypical EPEC (aEPEC). A total of 15 (83.3%) of the EPEC isolated belonged to β intimin subtype gene, while the remaining 3 EPEC isolates possessed the intimin έ subtype. No α and γ intimin subtypes were detected. Traditional EPEC serotypes O114:H14 were detected only in tEPEC strains. Marked resistance to β-lactam agents were observed but no ESBL-producing tEPEC or aEPEC was detected. Conclusions: This is the first report of intimin subtype genes in Abuja, Nigeria. EPEC isolates of diverse serotypes resistant to β-lactam antimicrobial agents were observed. These data will be useful in facilitating the characterization of intimin variants of EPEC and some Shiga toxin-producing E. coli (STEC) in humans and other animal species.

scholarly journals Multiple evolutionary trajectories for non-O157 Shiga toxigenic Escherichia coli

2019 ◽  
Author(s):  
Nabil-Fareed Alikhan ◽  
Nathan L. Bachmann ◽  
Nouri L. Ben Zakour ◽  
Nicola K. Petty ◽  
Mitchell Stanton-Cook ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Gene ◽  
Human Infection ◽  
Phylogenomic Analysis ◽  
E Coli ◽  
O Antigen ◽  
Food Borne Illness ◽  
Uremic Syndrome ◽  
Enterocyte Effacement ◽  
Genomic Regions

AbstractBackgroundShiga toxigenic Escherichia coli (STEC) is an emerging global pathogen and remains a major cause of food-borne illness with more severe symptoms including hemorrhagic colitis and hemolytic-uremic syndrome. Since the characterization of the archetypal STEC serotype, E. coli O157:H7, more than 250 STEC serotypes have been defined. Many of these non-O157 STEC are associated with clinical cases of equal severity as O157. In this study, we utilize whole genome sequencing of 44 STEC strains from eight serogroups associated with human infection to establish their evolutionary relationships and contrast this with their virulence gene profiles and established typing methods.ResultsOur phylogenomic analysis delineated these STEC strains into seven distinct lineages, each with a characteristic repertoire of virulence factors. Some lineages included commensal or other E. coli pathotypes. Multiple independent acquisitions of the Locus for Enterocyte Effacement were identified, each associated with a distinct repertoire of effector genes. Lineages were inconsistent with O-antigen typing in several instances, consistent with lateral gene transfer within the O-antigen locus. STEC lineages could be defined by the conservation of clustered regularly interspaced short palindromic repeats (CRISPRs), however, no CRISPR profile could differentiate STEC from other E. coli strains. Six genomic regions (ranging from 500 bp - 10 kbp) were found to be conserved across all STEC in this dataset and may dictate interactions with Stx phage lysogeny.ConclusionsThe genomic analyses reported here present non-O157 STEC as a diverse group of pathogenic E. coli emerging from multiple lineages that independently acquired mobile genetic elements that promote pathogenesis.

scholarly journals Afa, a Diffuse Adherence Fibrillar Adhesin Associated with Enteropathogenic Escherichia coli

2002 ◽  
Vol 70 (5) ◽  
pp. 2681-2689 ◽  
Author(s):  
Rogéria Keller ◽  
Juana G. Ordoñez ◽  
Rosana R. de Oliveira ◽  
Luiz R. Trabulsi ◽  
Thomas J. Baldwin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Chromosomal Region ◽  
Enzyme Electrophoresis ◽  
Enteropathogenic Escherichia Coli ◽  
Epec Strain ◽  
Infantile Diarrhea ◽  
E Coli ◽  
Multilocus Enzyme Electrophoresis ◽  
Typical Epec

ABSTRACT O55 is one of the most frequent enteropathogenic Escherichia coli (EPEC) O serogroups implicated in infantile diarrhea in developing countries. Multilocus enzyme electrophoresis analysis showed that this serogroup includes two major electrophoretic types (ET), designated ET1 and ET5. ET1 corresponds to typical EPEC, whilst ET5 comprises strains with different combinations of virulence genes, including those for localized adherence (LA) and diffuse adherence (DA). Here we report that ET5 DA strains possess a DA adhesin, designated EPEC Afa. An 11.6-kb chromosomal region including the DA adhesin operon from one O55:H− ET5 EPEC strain was sequenced and found to encode a protein with 98% identity to AfaE-1, an adhesin associated with uropathogenic E. coli. Although described as an afimbrial adhesin, we show that both AfaE-1 and EPEC Afa possess fine fibrillar structures. This is the first characterization and demonstration of an Afa adhesin associated with EPEC.

Isolation of atypical enteropathogenic Escherichia coli from children with and without diarrhoea in Delhi and the National Capital Region, India

2010 ◽  
Vol 59 (10) ◽  
pp. 1156-1162 ◽  
Author(s):  
Pankaj Kumar Ghosh ◽  
Arif Ali
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Agents ◽  
Virulence Gene ◽  
Healthy Children ◽  
National Capital Region ◽  
Capital Region ◽  
E Coli ◽  
Atypical Epec ◽  
National Capital ◽  
Typical Epec

A total of 17 typical and atypical enteropathogenic Escherichia coli (EPEC) were isolated from 396 children with and without diarrhoea. Out of 12 EPEC isolates from patients with diarrhoea, 3 (25 %) were atypical EPEC while 9 (75 %) were typical EPEC. It was observed that atypical EPEC strains had colonized the intestines of healthy children and its isolation rates were higher in healthy children than in children with diarrhoea. Interestingly all of the atypical EPEC isolates carried a megaplasmid, mostly comparable with the size of EPEC adherence factor (EAF) encoding gene but no virulence gene was detected in this megaplasmid. Studies also indicated that multidrug resistance EPEC are emerging and all the atypical EPEC strains showed significantly less resistance to all antimicrobial agents used in this study than typical EPEC. This study also supports the opinion that Shiga toxin-producing E. coli does not pose a major threat to human health in India. Subtyping analysis reveals that eae-α1, eae-β2 and eae-λ could be common EPEC subtypes prevalent in children with diarrhoea in Delhi. The present study is believed to be the first report of the detection of atypical EPEC from children without diarrhoea and records of isolation of eae-γ1, eae-γ2 and the rare eae-λ subtype in India. The data also indicated that typical EPEC are a common cause of diarrhoea and atypical EPEC are emerging as colonizers of the intestine of children with and without diarrhoea in Delhi and the National Capital Region, India.

scholarly journals Molecular Characterization Reveals Similar Virulence Gene Content in Unrelated Clonal Groups of Escherichia coli of Serogroup O174 (OX3)

2007 ◽  
Vol 190 (4) ◽  
pp. 1344-1349 ◽  
Author(s):  
Cheryl L. Tarr ◽  
Adam M. Nelson ◽  
Lothar Beutin ◽  
Katharina E. P. Olsen ◽  
Thomas S. Whittam
Keyword(s):  
Escherichia Coli ◽  
Severe Disease ◽  
Virulence Gene ◽  
Gene Profiling ◽  
Gene Content ◽  
Farm Animals ◽  
Shiga Toxins ◽  
E Coli ◽  
Uremic Syndrome ◽  
Enterocyte Effacement

ABSTRACT Most severe illnesses that are attributed to Shiga toxin-producing Escherichia coli are caused by isolates that also carry a pathogenicity island called the locus of enterocyte effacement (LEE). However, many cases of severe disease are associated with LEE-negative strains. We characterized the virulence gene content and the evolutionary relationships of Escherichia coli isolates of serogroup O174 (formerly OX3), strains of which have been implicated in cases of hemorrhagic colitis and hemolytic uremic syndrome. A total of 56 isolates from humans, farm animals, and food were subjected to multilocus virulence gene profiling (MVGP), and a subset of 16 isolates was subjected to multilocus sequence analysis (MLSA). The MLSA revealed that the O174 isolates fall into four separate evolutionary clusters within the E. coli phylogeny and are related to a diverse array of clonal groups, including enteropathogenic E. coli 2 (EPEC 2), enterohemorrhagic E. coli 2 (EHEC 2), and EHEC-O121. Of the 15 genes that we surveyed with MVGP, only 6 are common in the O174 strains. The different clonal groups within the O174 serogroup appear to have independently acquired and maintained similar sets of genes that include the Shiga toxins (stx 1 and stx 2) and two adhesins (saa and iha). The absence of certain O island (OI) genes, such as those found on OI-122, is consistent with the notion that certain pathogenicity islands act cooperatively with the LEE island.

scholarly journals A Localized Adherence-Like Pattern as a Second Pattern of Adherence of Classic Enteropathogenic Escherichia coli to HEp-2 Cells That Is Associated with Infantile Diarrhea

1999 ◽  
Vol 67 (7) ◽  
pp. 3410-3415 ◽  
Author(s):  
Isabel C. A. Scaletsky ◽  
Margareth Z. Pedroso ◽  
Carlos A. G. Oliva ◽  
Rozane L. B. Carvalho ◽  
Mauro B. Morais ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acute Diarrhea ◽  
Gastrointestinal Symptoms ◽  
Secretory Diarrhea ◽  
Persistent Diarrhea ◽  
Infantile Diarrhea ◽  
E Coli ◽  
Typical Epec ◽  
Relationship Of

ABSTRACT Escherichia coli strains that cause nonbloody diarrhea in infants are known to present three distinct patterns of adherence to epithelial cells, namely, localized (LA), diffuse (DA), and aggregative (AA) adherence. Strains with LA (typical EnteropathogenicEscherichia coli [EPEC]) are well recognized as a cause of secretory diarrhea, but the role of strains with DA (DAEC) is controversial, and strains with AA (EAEC) have been more frequently related to persistent diarrhea whereas its relationship with acute diarrhea is not well defined. To determine the relationship of the different types of E. coli adherence patterns with acute diarrhea (lasting less than 14 days) and persistent diarrhea (lasting more than 14 days) in São Paulo, Brazil, we studied stool specimens from 40 infants under 1 year of age with diarrhea and 40 age-matched control infants without any gastrointestinal symptoms. Twenty-eight (35.0%) of eighty cases yielded adherent E. coli (HEp-2 cells). Strains with localized and aggregative adherence were associated with acute and persistent diarrhea. A total of 11.2% of the adherent strains were typical EPEC serotypes and hybridized with the enteroadherence factor probe; 5.0% were EAEC and hybridized with the EAEC probe. DAEC strains were isolated from 10.0% of patients and 7.5% of controls and did not hybridize with the two probes used (daaC and AIDA-I). Strains with a localized adherence-like pattern (atypical EPEC) were found significantly more frequently (P = 0.028) in cultures from children with diarrhea (17.5%) than in controls (2.5%).

scholarly journals Genome evolution and the emergence of pathogenicity in avian Escherichia coli

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Leonardos Mageiros ◽  
Guillaume Méric ◽  
Sion C. Bayliss ◽  
Johan Pensar ◽  
Ben Pascoe ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Association Studies ◽  
Virulence Gene ◽  
Systemic Infection ◽  
Disease Status ◽  
Evolutionary Mechanisms ◽  
Sustainable Food ◽  
E Coli ◽  
Common Birds ◽  
Systemic Infections

AbstractChickens are the most common birds on Earth and colibacillosis is among the most common diseases affecting them. This major threat to animal welfare and safe sustainable food production is difficult to combat because the etiological agent, avian pathogenic Escherichia coli (APEC), emerges from ubiquitous commensal gut bacteria, with no single virulence gene present in all disease-causing isolates. Here, we address the underlying evolutionary mechanisms of extraintestinal spread and systemic infection in poultry. Combining population scale comparative genomics and pangenome-wide association studies, we compare E. coli from commensal carriage and systemic infections. We identify phylogroup-specific and species-wide genetic elements that are enriched in APEC, including pathogenicity-associated variation in 143 genes that have diverse functions, including genes involved in metabolism, lipopolysaccharide synthesis, heat shock response, antimicrobial resistance and toxicity. We find that horizontal gene transfer spreads pathogenicity elements, allowing divergent clones to cause infection. Finally, a Random Forest model prediction of disease status (carriage vs. disease) identifies pathogenic strains in the emergent ST-117 poultry-associated lineage with 73% accuracy, demonstrating the potential for early identification of emergent APEC in healthy flocks.

scholarly journals Clinical and Molecular Correlates of Escherichia coli Bloodstream Infection from Two Geographically Diverse Centers in Rochester, Minnesota, and Singapore

2018 ◽  
Vol 62 (10) ◽  
Author(s):  
Shehara M. Mendis ◽  
Shawn Vasoo ◽  
Brian D. Johnston ◽  
Stephen B. Porter ◽  
Scott A. Cunningham ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Odds Ratio ◽  
Virulence Gene ◽  
Fluoroquinolone Resistance ◽  
Content Type ◽  
E Coli ◽  
Gene Profiles ◽  
Clonal Distribution ◽  
To Receive ◽  
Community Onset

ABSTRACT Escherichia coli bacteremia is caused mainly by sequence type complex 131 (STc131) and two clades within its fluoroquinolone-resistance-associated H30 subclone, H30R1 and H30Rx. We examined clinical and molecular correlates of E. coli bacteremia in two geographically distinct centers. We retrospectively studied 251 unique E. coli bloodstream isolates from 246 patients (48 from the Mayo Clinic, Rochester, MN [MN], and 198 from Tan Tock Seng Hospital, Singapore [SG]), from October 2013 through March 2014. Isolates underwent PCR for phylogroup, STc, blaCTX-M type, and virulence gene profiles, and medical records were reviewed. Although STc131 accounted for 25 to 27% of all E. coli bacteremia isolates at each site, its extended-spectrum-β-lactamase (ESBL)-associated H30Rx clade was more prominent in SG than in MN (15% versus 4%; P = 0.04). In SG only, patients with STc131 (versus other E. coli STc isolates) were more likely to receive inactive initial antibiotics (odds ratio, 2.8; P = 0.005); this was true specifically for patients with H30Rx (odds ratio, 7.0; P = 0.005). H30Rx comprised 16% of community-onset bacteremia episodes in SG but none in MN. In SG, virulence scores were higher for H30Rx than for H30R1, non-H30 STc131, and non-STc131 isolates (P < 0.02 for all comparisons). At neither site did mortality differ by clonal status. The ESBL-associated H30Rx clade was more prevalent and more often of community onset in SG, where it predicted inactive empirical treatment. The clonal distribution varies geographically and has potentially important clinical implications. Rapid susceptibility testing and clonal diagnostics for H30/H30Rx might facilitate earlier prescribing of active therapy.

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