Flask-shaped ulcers in the colon are characteristic of which organism?

Flask-shaped ulcers in the colon are a hallmark of infection caused by Entamoeba histolytica. This organism is known for causing amoebic dysentery, which is characterized by the formation of these specific ulcers due to the invasion of the intestinal mucosa. The ulcers have a distinctive inverted flask shape because they extend from a wider base towards a narrower top, reflecting the way in which the parasite invades and destroys tissue.

Entamoeba histolytica is transmitted through the fecal-oral route, often via contaminated water or food. It is important to recognize the clinical presentation associated with this infection, as it can lead to severe abdominal symptoms and complications, including colitis and systemic spread if left untreated. This underscores the relevance of identifying the organism correctly based on morphological features observed in clinical cases.

Other organisms listed do not cause flask-shaped ulcers in the colon. For instance, Giardia lamblia typically leads to a different type of gastroenteritis, characterized by malabsorption rather than ulceration. Clostridium difficile can cause colitis but through a different pathological mechanism, often resulting in pseudomembranous colitis rather than flask-shaped ulcers. Lastly, Salmonella enterica causes gastroenteritis that does not typically result