Skip Navigation
Skip Website Tools

E. coli

Skip Content Marketing
  • Share this:
  • submit to facebook
  • Tweet it
  • submit to reddit
  • submit to StumbleUpon
  • submit to Google +


Hundreds of E. coli strains are harmless, including those that thrive in the intestinal tracts of humans and other warm-blooded animals. These strains are part of the protective microbial community in the intestine and are essential for general health. Other strains cause serious poisoning in humans by making a toxin called Shiga toxin. These bacteria are called “Shiga toxin-producing” E. coli, or STEC for short. The most commonly identified STEC in North America is E. coli O157:H7, according to the Centers for Disease Control and Prevention (CDC). CDC estimates that 265,000 STEC infections occur each year in the United States. Approximately 36 percent of these infections are caused by E. coli O157:H7.

Cattle are the main sources of E. coli O157:H7, but these bacteria are also in other domestic and wild mammals. The bacteria often cause bloody diarrhea and can lead to kidney failure, especially in young children or in people with weakened immune systems. Most illness has been associated with contaminated food or water, contact with an infected person, or contact with animals that carry the bacteria.

In addition to E. coli O157:H7, there are other serotypes of E. coli, named enterohemorrhagic E. coli, that cause the same serious illnesses. Other forms of E. coli that cause diarrheal disease include:

  • Enterotoxigenic E. coli (ETEC) is a leading bacterial cause of diarrhea in the developing world. Each year, about 210 million cases and 380,000 deaths occur, mostly in children, from ETEC, according to the World Health Organization. ETEC is the most common cause of traveler's diarrhea and affects troops deployed overseas.
  • Enteropathogenic E. coli (EPEC) is a bacterial cause of persistent diarrhea that can last 2 weeks or more. It spreads to humans through contact with contaminated water or infected animals and is common in developing countries. In industrialized countries, the frequency of these organisms has decreased, but they continue to be an important cause of diarrhea, according to CDC.

back to top

Last Updated November 15, 2011