How does Enterohemorrhagic E. coli (EHEC) cause disease?

How does Enterohemorrhagic E. coli (EHEC) cause disease?

• A. Through cholera toxin-like mechanism
• B. Attachment via fimbriae & intimin > effacement; Shiga-toxin producing causing hemorrhagic diarrhea
• C. Invasive necrosis only
• D. No toxins

Answer: (B)

Enterohemorrhagic E. coli causes disease through a combination of tight adherence to intestinal cells and a potent toxin. It uses fimbriae and the intimin/Tir system to attach to enterocytes and create attaching-and-effacing lesions, which disrupt the microvilli and impair absorption. In addition, it produces Shiga toxins (Stx1/Stx2) that inhibit protein synthesis in host cells, leading to cell injury and death. This toxin-mediated damage in the gut can cause hemorrhagic colitis and, if absorbed systemically, can trigger hemolytic uremic syndrome. This pattern is different from a cholera toxin–like secretory mechanism and from invasive necrosis alone, and it relies on toxins rather than being toxin-free.

Enterohemorrhagic E. coli causes disease through a combination of tight adherence to intestinal cells and a potent toxin. It uses fimbriae and the intimin/Tir system to attach to enterocytes and create attaching-and-effacing lesions, which disrupt the microvilli and impair absorption. In addition, it produces Shiga toxins (Stx1/Stx2) that inhibit protein synthesis in host cells, leading to cell injury and death. This toxin-mediated damage in the gut can cause hemorrhagic colitis and, if absorbed systemically, can trigger hemolytic uremic syndrome. This pattern is different from a cholera toxin–like secretory mechanism and from invasive necrosis alone, and it relies on toxins rather than being toxin-free.