Final answer:
STEC infection leads to effacement of enterocytes in the large intestine, causing severe stomach cramps and bloody diarrhea. E. coli strains like EPEC and ETEC disrupt normal intestinal function through structural damage and toxin production. Management includes rehydration and, in severe or persistent cases, antibiotics.
Step-by-step explanation:
STEC infection results in effacement of enterocytes, leading to the destruction of the intestinal lining, which is particularly severe in the large intestine. The destruction of this lining is due to various mechanisms such as the production of Shiga toxin by certain strains like S. dysenteriae and the ability of other types of E. coli, such as Enteropathogenic E. coli (EPEC) and Enterotoxigenic E. coli (ETEC), to interfere with normal cell functions. EPEC, for instance, injects a protein called Tir that causes rearrangement of host cell actin, leading to pedestal formation on which the bacteria sit, a process crucial for the effacement. ETEC secretes toxins that cause chloride ions and water to be expelled from intestinal cells, resulting in diarrhea. In severe cases, the infection can lead to complications like hemolytic uremic syndrome (HUS) or chronic post-infection irritable bowel syndrome (IBS).
Patients suffering from such infections typically experience severe stomach cramps, bloody diarrhea, and vomiting. If the infection becomes systemic, it may lead to life-threatening conditions. To manage the symptoms and prevent dehydration, patients are advised to drink lots of fluids. In some cases, especially when symptoms persist or are severe, antibiotic treatment may be necessary.