How does enteroinvasive E. coli (EIEC) cause disease?

How does enteroinvasive E. coli (EIEC) cause disease?

• A. It produces toxins that are excreted into lumen.
• B. It is an intracellular pathogen that invades the intestinal epithelium into submucosa and multiplies within macrophages.
• C. It remains extracellular and damages mucosa via toxins.
• D. It only attaches but does not invade.

Answer: (B)

Enteroinvasive E. coli causes disease by invading the intestinal mucosa and multiplying inside host cells, not by secreting toxins into the lumen. It behaves like Shigella, using invasion mechanisms to cross the intestinal epithelium, reach the submucosa, and be taken up by macrophages where it can replicate. This intracellular invasion triggers a strong inflammatory response, mucosal ulceration, and an inflammatory exudate, leading to dysentery-like symptoms such as fever, abdominal cramps, and bloody diarrhea. Because the illness comes from invasion and intracellular growth rather than toxin production, this description best fits the organism.

Enteroinvasive E. coli causes disease by invading the intestinal mucosa and multiplying inside host cells, not by secreting toxins into the lumen. It behaves like Shigella, using invasion mechanisms to cross the intestinal epithelium, reach the submucosa, and be taken up by macrophages where it can replicate. This intracellular invasion triggers a strong inflammatory response, mucosal ulceration, and an inflammatory exudate, leading to dysentery-like symptoms such as fever, abdominal cramps, and bloody diarrhea. Because the illness comes from invasion and intracellular growth rather than toxin production, this description best fits the organism.