Medicine & USMLE

Enterohemorrhagic E. Coli (EHEC)

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Bacteria - Gram Negative
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  10. Salmonella Overview
  11. Salmonella typhi
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  14. Yersinia enterocolitica
  15. Escherichia coli: Overview
  16. Enterohemorrhagic E. Coli (EHEC)
  17. Enterotoxigenic E. Coli (ETEC)
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  • Enterohemorrhagic E. coli (EHEC)
    • Virulence Factors
      • O157:H7 is most common EHEC serotype in US
      • Produces Shiga-like toxin (verotoxin)
        • inactivates 60s ribosomal subunit, stopping protein production and leading to cell death
        • Major mediator of pathogenicity; toxin-mediated enterocyte death and intestinal hemorrhage
        • Similar to the mechanism of shiga toxin in Shigella spp.
          • Contrast vs. Shigella, where toxin plays minor role in pathogenesis
    • Transmission
      • Ingested via undercooked meat (beef)
        • unpasteurized milk, contaminated water are also sources
    • Presentation
      • Bloody Diarrhea
      • May be complicated by Hemolytic-uremic syndrome (HUS)
        • Triad of hemolytic anemia, thrombocytopenia, and kidney injury