All blood, No stool: enterohemorrhagic Escherichia coli O157:H7 infection

Yoon, Jang Won; Hovde, Carolyn J.

doi:10.4142/jvs.2008.9.3.219

Cited by 67 publications

(51 citation statements)

References 150 publications

(197 reference statements)

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“…According to the stepwise evolutionary model for O157:H7 (8), strain G5101 was thought to be a precursor of SOR Ϫ , GUD Ϫ O157:H7 strains (9). It was previously assumed that clinical O157:H7 isolates carry a virulence plasmid resembling pO157 (24,30). However, in this study we showed that O157:H7 strains could carry virulence plasmids other than pO157.…”

Section: Discussioncontrasting

confidence: 47%

Complete DNA Sequence Analysis of Enterohemorrhagic Escherichia coli Plasmid pO157_2 in β-Glucuronidase-Positive E. coli O157:H7 Reveals a Novel Evolutionary Path

et al. 2012

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Strains of enterohemorragic Escherichia coli (EHEC) O157:H7 that are non-sorbitol fermenting (NSF) and ␤-glucuronidase negative (GUD ؊ ) carry a large virulence plasmid, pO157 (>90,000 bp), whereas closely related sorbitol-fermenting (SF) E. coli O157:H ؊ strains carry plasmid pSFO157 (>120,000 bp). GUD ؉ NSF O157:H7 strains are presumed to be precursors of GUD ؊ NSF O157:H7 strains that also carry pO157. In this study, we report the complete sequence of a novel virulence plasmid, pO157-2 (89,762 bp), isolated from GUD ؉ NSF O157:H7 strain G5101. PCR analysis confirmed the presence of pO157-2 in six other strains of GUD ؉ NSF O157:H7. pO157-2 carries genes associated with virulence (e.g., hemolysin genes) and conjugation (tra and trb genes) but lacks katP and espP present in pO157. Comparative analysis of the three EHEC plasmids shows that pO157-2 is highly related to pO157 and pSFO157 but not ancestral to pO157. These results indicated that GUD ؉ NSF O157:H7 strains might not be direct precursors to GUD ؊ NSF O157:H7 as previously proposed but rather have evolved independently from a common ancestor. N on-sorbitol-fermenting (NSF) enterohemorrhagic Escherichia coli (EHEC) of serotype O157:H7 frequently causes large outbreaks of severe enteric infections including bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome worldwide (7, 10). It has been proposed that highly pathogenic E. coli O157:H7 arose from an ancestral enteropathogenic E. coli (EPEC) O55:H7 through sequential acquisition of virulence factors, phenotypic traits, and serotypic change (8,9,28). In this evolutionary model for O157:H7, six clonal complexes (A1 to A6) carrying characteristic traits were proposed. Ancestral O55:H7 EPEC strains belong to clonal complexes (CCs) A1 and A2. The somatic (O) antigen change from O55 to O157 gave rise to a hypothetical intermediary (CC A3) (29). This was followed by a divergence in two separate O157 clonal lineages of nonmotile sorbitol-fermenting (SF) O157:H Ϫ strains (A4) and non-sorbitol-fermenting (NSF) O157:H7 strains (CC A5). The most typical O157:H7 phenotype at present (CC A6) is believed to have emerged from CC A5 strains by the loss of ␤-glucuronidase activity (GUD Ϫ ), caused by a mutational inactivation of the uidA (9). These CC A6 strains have spread widely into disparate locales and now account for most food-borne illness caused by EHEC (29).The pathogenicity of O157:H7 is among other factors associated with the possession of a large EHEC virulence plasmid. CC A6 strains carry pO157 (ϳ90 kb), and CC A4 strains carry a larger plasmid (ϳ120 kb), namely, pSFO157 (2). Different genes and gene clusters including the EHEC hemolysin (hly) operon located on pO157 have been linked to virulence (21, 23). pO157 furthermore carries katP, encoding a periplasmic catalase-peroxidase (3); a type II secretion system (etp operon) (22), toxB, involved in adherence (26); and espP, encoding a secreted serine protease (4). Although NSF O157 and SF O157 strains are closely related and share virulence facto...

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Section: Discussioncontrasting

confidence: 47%

Complete DNA Sequence Analysis of Enterohemorrhagic Escherichia coli Plasmid pO157_2 in β-Glucuronidase-Positive E. coli O157:H7 Reveals a Novel Evolutionary Path

et al. 2012

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“…EHEC strains are typically known for their ability to produce Shiga toxin and to induce A/E lesions in the host's gut epithelium. While these strains are pathogenic for humans, they can reside peacefully as reservoirs of infection in many production animal types including cattle, swine, and poultry (197). Disease outbreaks in humans are usually associated with the ingestion of some type of food product such as undercooked beef, fresh vegetables, unpasteurized milk and cider, and salami.…”

Section: Ehec and Stec Virulence Plasmidsmentioning

confidence: 99%

“…EHEC strains are a subset of Shiga toxin-producing E. coli (STEC) strains responsible for hemorrhagic colitis (HC) and hemolytic-uremic syndrome (HUS) in humans (197). Although E. coli strains of several serogroups are members of the EHEC pathotype, E. coli strains of the O157 serogroup are responsible for the most severe cases of these diseases (91,128).…”

Section: Ehec and Stec Virulence Plasmidsmentioning

confidence: 99%

“…While the annual health care burden associated with EHEC-caused infections is not overwhelming ($0.3 to $0.7 billion per year in the United States), the severity of the disease is alarming. In young children and the elderly particularly, this disease can progress to HUS, a development that is accompanied by a dramatic increase in rates of morbidity and mortality (197).…”

Section: Ehec and Stec Virulence Plasmidsmentioning

confidence: 99%

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Pathogenomics of the Virulence Plasmids ofEscherichia coli

Johnson

Nolan

2009

Microbiol Mol Biol Rev

376

369

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SUMMARY Bacterial plasmids are self-replicating, extrachromosomal elements that are key agents of change in microbial populations. They promote the dissemination of a variety of traits, including virulence, enhanced fitness, resistance to antimicrobial agents, and metabolism of rare substances. Escherichia coli, perhaps the most studied of microorganisms, has been found to possess a variety of plasmid types. Included among these are plasmids associated with virulence. Several types of E. coli virulence plasmids exist, including those essential for the virulence of enterotoxigenic E. coli, enteroinvasive E. coli, enteropathogenic E. coli, enterohemorrhagic E. coli, enteroaggregative E. coli, and extraintestinal pathogenic E. coli. Despite their diversity, these plasmids belong to a few plasmid backbones that present themselves in a conserved and syntenic manner. Thanks to some recent research, including sequence analysis of several representative plasmid genomes and molecular pathogenesis studies, the evolution of these virulence plasmids and the implications of their acquisition by E. coli are now better understood and appreciated. Here, work involving each of the E. coli virulence plasmid types is summarized, with the available plasmid genomic sequences for several E. coli pathotypes being compared in an effort to understand the evolution of these plasmid types and define their core and accessory components.

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“…A major and natural reservoir of Escherichia coli O157:H7 is healthy cattle ( Yoon andHovde 2008, Whitworth et al 2010). According to studies conducted both in Poland, the United Kingdom and the United States, Escherichia coli O157 isolation frequency from cattle is 0.…”

Section: Introductionmentioning

confidence: 99%

Influence of temperature on survival of Escherichia coli O157:H7 in stored cattle slurry with respect to environmental biosafety

Wroński¹,

Budzińska²,

Szejniuk³

et al. 2012

Polish Journal of Veterinary Sciences

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The aim of the study was to determine the influence of temperature, i.e. 4 and 20 o C on the Escherichia coli O157:H7 survival time in a stored cattle slurry in a laboratory model experiment. The results of this investigation indicated that the tested microorganisms underwent a gradual elimination in the cattle slurry, whereas their inactivation rate was clearly dependent on the temperature. A higher survival rate was found in Escherichia coli O157:H7 at 4 o C where a theoretical survival time of these microorganisms, determined using a regression analysis, amounted to 83 days. Our study indicates that there is a necessity for the slurry to undergo hygienization processes and that a constant monitoring of liquid animal excreta in search for pathogenic microorganisms is required.

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All blood, No stool: enterohemorrhagic Escherichia coli O157:H7 infection

Cited by 67 publications

References 150 publications

Complete DNA Sequence Analysis of Enterohemorrhagic Escherichia coli Plasmid pO157_2 in β-Glucuronidase-Positive E. coli O157:H7 Reveals a Novel Evolutionary Path

Complete DNA Sequence Analysis of Enterohemorrhagic Escherichia coli Plasmid pO157_2 in β-Glucuronidase-Positive E. coli O157:H7 Reveals a Novel Evolutionary Path

Pathogenomics of the Virulence Plasmids ofEscherichia coli

Influence of temperature on survival of Escherichia coli O157:H7 in stored cattle slurry with respect to environmental biosafety

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