Diarrhea (cont.)

Disease-causing bacteria usually invade the small intestines and colon and cause enterocolitis (inflammation of the small intestine and colon). Bacterial enterocolitis is characterized by signs of inflammation (blood or pus in the stool, fever) and abdominal pain and diarrhea. Campylobacter jejuni is the most common bacterium that causes acute enterocolitis in the U.S. Other bacteria that cause enterocolitis include Shigella, Salmonella, and EPEC. These bacteria usually are acquired by drinking contaminated water or eating contaminated foods such as vegetables, poultry, and dairy products.

Enterocolitis caused by the bacterium Clostridium difficile is unusual because it often is caused by antibiotic treatment. Clostridium difficile is also the most common nosocomial infection (infection acquired while in the hospital) to cause diarrhea. Unfortunately, infection also is increasing among individuals who have neither taken antibiotics or been in the hospital.

E. coli O157:H7 is a strain of E. coli that produces a toxin that causes hemorrhagic enterocolitis (enterocolitis with bleeding). There was a famous outbreak of hemorrhagic enterocolitis in the U.S. traced to contaminated ground beef in hamburgers (hence it is also called hamburger colitis). Approximately 5% of patients infected with E. coli O157:H7, particularly children, can develop hemolytic uremic syndrome (HUS), a syndrome that can lead to kidney failure. Some evidence suggests that prolonged use of anti-diarrhea agents or use of antibiotics may increase the chance of developing HUS.

Source: MedicineNet.com
http://www.medicinenet.com/diarrhea/article.htm