Hemorrhagic colitis (inflammation of the colon) is characterized by grossly bloody diarrhea and typically follows 2-7 days after Shiga toxin-producing E. coli O157:H7 (STEC) is ingested. In severe cases, a colectomy (surgery to remove all or part of the colon) may be necessary.
Hemorrhagic colitis is typically caused by Shiga toxins produced by E. coli O157:H7 binding to epithelial cells, such as those that line the intestines. After the E. coli attach, they produce Shiga toxins which is then released from the bacterium and transported inside the host cell. Once inside the host cell, Shiga toxins interferes with protein synthesis which causes the cell to die, either through apoptosis or necrosis. This process of intestinal epithelial cell destruction caused by Shiga toxin is called hemorrhagic colitis.
Watery diarrhea usually precedes the bloody diarrhea by one or two days. Other symptoms to look out for include:
- muscle pain
- fever (only in 5-20% of patients)
Bad Bug Book. 2001. Escherichia coli O157:H7. U.S. Food and Drug Administration. Online at http://www.foodsafety.gov/~mow/chap15.html.
Tarr PI, Neill MA. 2001. Escherichia coli O157:H7. Gastroenterology Clinics of North America. 303:3: 735-751.