Foodborne E. Coli

by National Institute of Health

Outbreaks of foodborne disease caused by E. coli (Escherichia coli) bacteria have become a serious problem in this country. E. coli O157:H7 (one type of the bacteria) has caused illness and major disease outbreaks in the United States. The Centers for Disease Control and Prevention (CDC) estimates 73,000 cases of infection with E. coli O157:H7 and 61 deaths occur in this country each year.

While there are many types of E. coli bacteria, only certain types cause foodborne illness. Hundreds of harmless strains of E. coli can be found widely in nature, including the intestinal tracts of humans and other warm-blooded animals. Disease-causing strains, however, are a frequent cause of both intestinal and urinary-genital tract infections.

In 1982, scientists identified the first dangerous foodborne strain in the United States. The type of harmful foodborne E. coli most commonly found in this country is called O157:H7, which refers to chemical compounds found on the bacterium's surface. Cattle are the main sources of E. coli O157:H7, but these bacteria can be found in other domestic and wild mammals.

Several different strains of harmful E. coli can cause diarrheal disease.

Particularly dangerous types E. coli, such as E. coli O157:H7, produce one or more Shiga toxins that can severely damage the lining of your intestines and kidneys. These types of strains are called Shiga toxin-producing E. coli (STEC). STEC often causes bloody diarrhea and can lead to kidney failure in children or people with weakened immune systems.

Enterotoxigenic E. coli (ETEC), which produce a different toxin, can cause diarrhea. These strains typically cause so-called travelers' diarrhea because they commonly contaminate food and water in developing countries.

Enteropathogenic E. coli (EPEC) cause persistent diarrhea (lasting 2 weeks or more) and are more common in developing countries where they can be transmitted to humans through contaminated water or contact with infected animals.

Other types of E. coli, including O26:H11 and O111:H8, also have been found in the United States and can cause disease in people.

Transmission

E. coli O157:H7 and its toxins have been found in certain foods and liquids.

• Undercooked or raw hamburgers
• Salami
• Alfalfa sprouts
• Lettuce
• Unpasteurized milk, apple juice, and apple cider
• Contaminated well water

Other ways you can get infected with E. coli include

• Swallowing unchlorinated or underchlorinated water in swimming pools contaminated by human feces
• Swimming in sewage-contaminated water
• Having direct contact with an infected family member
• Having direct contact with infected child in a child care center

Symptoms

E. coli O157:H7 toxin can damage the lining of your intestines and cause other symptoms including

• Nausea
• Severe abdominal cramps
• Watery or very bloody diarrhea
• Fatigue

You might develop low-grade fever or vomiting. Symptoms usually begin from 2 to 5 days after you eat contaminated food or drink contaminated liquids and may last for 8 days. You should recover completely from the disease.

Diagnosis

Your health care provider can use lab tests to identify E. coli O157:H7 or Shiga toxin in your stool if you are infected. CDC recommends that any one who suddenly has diarrhea with blood get their stool tested for E. coli O157:H7.

Treatment

If you are like most people infected with E. coli O157:H7, you will get better within 5 to 10 days without treatment. Antibiotics are usually not helpful, and health care experts don't recommend taking antidiarrheal medicines.

Prevention

• Wash your hands thoroughly after going to the bathroom or changing diapers.
• Eat only thoroughly cooked ground beef.
• Cook ground beef products to an internal temperature of 160 degrees Fahrenheit.
• Avoid unpasteurized milk and juices.
• Wash fresh fruits and vegetables thoroughly before eating raw or cooked.
• Keep raw meat separate from ready-to-eat foods.

Complications

Hemolytic uremic syndrome (HUS), a serious complication of STEC, can lead to kidney failure. In North America, HUS is the most common cause of acute kidney failure in children, who are particularly prone to this complication. This life-threatening condition is usually treated in an intensive care unit of a hospital, sometimes with blood transfusions and kidney dialysis.

About 8 percent of people with HUS have other lifelong complications, such as high blood pressure, seizures, blindness, paralysis, and the effects of having part of their intestines removed.

About the Author

NIH is the nation's medical research agency - making important medical discoveries that improve health and save lives. The National Institutes of Health (NIH), a part of the U.S. Department of Health and Human Services, is the primary Federal agency for conducting and supporting medical research.