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Escherichia coli O157 Pennington H. (2010) The Lancet 376 (9750): 1428-1435

Escherichia coli O157 Pennington H. (2010) The Lancet 376 (9750): 1428-1435. Dr. Claudio Scotti. GI tract infections in the UK. Campylobacter Rotavirus Salmonella Norovirus Cryptosporidium Giardia Shigella Escherichia coli O157. Escherichia coli.

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Escherichia coli O157 Pennington H. (2010) The Lancet 376 (9750): 1428-1435

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  1. Escherichia coli O157Pennington H. (2010) The Lancet 376 (9750): 1428-1435 Dr. Claudio Scotti

  2. GI tract infections in the UK Campylobacter Rotavirus Salmonella Norovirus Cryptosporidium Giardia Shigella Escherichia coli O157

  3. Escherichia coli • Six different groups of pathogenic E. coli: - EPEC: enteropathogenic - ETEC: enterotoxigenic - EHEC: enterohaemorrhagic (VTEC) - EIEC: enteroinvasive - EAEC: enteroaggregative - DAEC: diffuse-aggregative

  4. E. coli O157 in England & Wales

  5. Typical features • Abdominal pain • Five or more bowel movements in the day before presentation • Non-bloody diarrhoea, becoming bloody after 1-4 days • No fever • 10-15% of patients develop haemolytic uraemic syndrome (HUS) 5-13 days after the onset of diarrhoea

  6. Haemolytic uraemic syndrome • Acute onset of renal impairment with oliguria or anuria and high concentrations of serum urea and creatinine • Platelet counts less than 15x109 cells/L • Microangiopathic haemolytic anaemia with haemoglobin <10 g/dL and with fragmented red cells in a peripheral blood smear

  7. The first oubreak • 1982, in Oregon and Michigan, USA • Bloody diarrhoea and severe abdominal cramps after eating hamburgers in a restaurant chain • First outbreak in the UK: 1983

  8. The largest outbreak • Sakai City, Japan, in 1996 • Associated with white radish sprouts served as school meals • 7,966 cases • 2,764 microbiologically confirmed • 106 with haemolytic uraemic syndrome (HUS)

  9. The source of E. coli O157 • Ruminants, particularly cattle (prevalence between 0.2 and 48.8%) and sheep • 80% of transmission arise from the 20% of animals that are most infectious (supershedders) • Secondary spread (20% of outbreak cases)

  10. Transmission of E. coli O157

  11. Transmission of E. coli O157

  12. Transmission of E. coli O157 • Quantitative microbial risk assessment showed that the risk is 100 times greater for visits to pastures than for consumption of burgers in the northeast of Scotland • Heavy rain is frequently associated with outbreaks (e.g. Glastonbury festival in 1997)

  13. Isolation rates, UK 1984-2008

  14. Incidence of infection • Per 100,000: • 4.7 in Scotland • 4 in Canada • 2.87 in Ireland • 2.74 in Japan • 2.1 in England and Wales • 1.3 in the USA • 0.43 in Germany • 0.08 in France

  15. Disease caused by E. coli O157 • 1996, in central Scotland, associated with meat from a butcher: 279 individuals, 17 people died from the direct effects of infection • Irish outbreak, water-borne spread: 18 individuals, 2 children with HUS • 2010 English outbreak on an open farm: 17 developed HUS (8 of them receiving dialysis)

  16. Typical features • HUS is most common in children younger than 5 years • In England and Scotland, between 1997 and 2001, 226 (65%) of the 350 cases occurred in this age group • Once an infection has been established, no therapeutic interventions are available to lessen the risk of the development of the HUS

  17. Outcomes of HUS

  18. Extrarenal effects • Increase in pancreatic enzymes and oedema • Necrosis of the colon wall • Myocardial damage • CNS damage (25% of cases), with seizures, paralysis, coma • Deaths are usually associated with severe extra-renal complications

  19. Virulence factors • Two different Shiga toxins (Stx1, Stx2) • Correlation with bloody diarrhoea and HUS • Shiga toxin binds to glycosphingolipidglobotriaosylceramide (Gb3), a cell surface receptor • In the human kidney, Gb3 is present on glomerular endothelial cell types and various tubular epithelial cell types

  20. Virulence factors • Enterocyte effacement genes: mediate the intimate attachment of bacteria to the intestinal epithelium • Several plasmid-encoded genes promoting adherence • Upregulation of flagellar and chemotaxis genes

  21. Prevention (failure points) • Failure during or after milk pasteurisation • Rare and light cooking of hamburger patties • Failure in municipal water chlorination • Failure to prevent cross-contamination or ready-to-eat foods by direct or indirect contact with raw meat • Handwashing

  22. Conclusion • Ground beef outbreaks still occur in the USA but are now associated with home-made burgers • A vaccine that shows promise has been developed • Investigation of “supershedders” (> reduction of ruminant carriage)

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