How does Enterohemorrhagic e coli differ from the that is normal flora in intestinal tract?
* Toxin production: EHEC produces one or more Shiga toxins (Stx1 and/or Stx2), which are potent cytotoxins responsible for the severe symptoms of EHEC infection. Normal flora E. coli strains do not produce Shiga toxins.
* Pathogenicity: EHEC strains are pathogenic and can cause serious illnesses such as hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS), especially in young children and the elderly. Normal flora E. coli strains are generally harmless or may have beneficial roles in the gut.
* Colonization: EHEC strains have specific virulence factors that enable them to adhere to and colonize the intestinal mucosa, facilitating the production and release of Shiga toxins. Normal flora E. coli strains have different colonization mechanisms and do not cause significant harm to the host.
* Transmission: EHEC is transmitted through the ingestion of contaminated food or water, or through contact with infected animals or individuals. Normal flora E. coli strains are acquired through the environment and are part of the gut microbiome.
Overall, Enterohemorrhagic E. coli differs from normal flora E. coli in terms of serotype, toxin production, pathogenicity, colonization, and transmission. While normal flora E. coli strains are usually harmless or even beneficial, EHEC strains have the potential to cause severe illnesses and require specific precautions to prevent infection.