E. coli (Escherichia coli) is a bacterial species found in the intestines of humans and animals. The presence of E. coli in the gut is both normal and beneficial to human health, as it prevents other harmful bacteria and pathogens from colonizing the gut. However, there are some small groups of pathogenic E. coli that can cause severe illness.
The most dangerous type of E. coli, known as E. coli O157:H7, causes severe, bloody diarrhea and can sometimes lead to kidney failure and even death. E. coli O157:H7 belongs to a group of bacteria that produce a toxin called Shiga toxin, known as a Shiga toxin-producing E. coli (STEC). Many of these STECs can make you just as sick as E. coli O157:H7.
Another severe complication associated with E. coli infection is hemolytic uremic syndrome (HUS), a condition brought about when E. coli toxins destroy red blood cells, injuring the kidneys. HUS can require intensive care treatment, kidney dialysis, and blood transfusions.
The U.S. Centers for Disease Control and Prevention (CDC) estimates that Shiga toxin-producing E. coli cause more than 265,000 illnesses each year in the U.S., with more than 3,600 hospitalizations and 30 deaths.
E. coli is spread through the feces of infected humans and animals and it can contaminate just about anything that can be ingested. Common sources include ground beef, unpasteurized meat, juice, dairy products, raw fruits and vegetables, and contaminated drinking water. Swimming in contaminated water and petting or handling livestock such as cows, sheep, and goats without thoroughly washing hands afterward are other ways people often become sickened by E. coli.
E. coli outbreaks occur every year in the U.S., but some of the largest outbreaks have been linked to fast food restaurants. In 1993, a five-state outbreak caused by contaminated meat in Jack in the Box restaurants sickened several hundred customers and led to the deaths of four children. Similar outbreaks occurred in Wisconsin Sizzler restaurants in 2000, which sickened more than 60 people and led to the death of a 3-year-old girl, and in five Taco Bell restaurants in 2006, when more than 70 customers were sickened, including eight who suffered from kidney failure as a result.
Also in 2006, two massive outbreaks of E. coli that federal authorities linked to raw spinach sickened about 200 people. Three people died after eating raw spinach and 31 suffered from kidney failure. Investigators eventually determined that the spinach had been grown on a cattle ranch that leased its land to a spinach grower.