Bureau of Communicable Disease

E. coli 0157:H7 Infection

What is E. coli O157:H7 infection?

E. coli are bacteria (germs) that normally live in the intestines of humans and animals. Although, most kinds of these bacteria are harmless, several can cause diarrhea. One particular type of E. coli called O157:H7 can cause severe diarrhea and kidney damage. In 2007, there were 27 cases of E. coli O157:H7 reported among New York City residents (rate of 0.3 cases per 100,000).

Who gets E. coli O157:H7 infections?

Anyone can become infected with E. coli O157:H7, but children are more likely to develop serious complications.

How is E. coli O157:H7 spread?

E. coli O157:H7 germs are mostly found in cattle. Food-borne infections are often associated with contaminated beef products that are not thoroughly cooked before eating. Other outbreaks have been traced to unpasteurized milk, or apple cider made from apples contaminated by cow manure. Direct person-to-person transmission can also occur.

What are the symptoms of E. coli O157:H7 infection?

People infected by E. coli O157:H7 can develop a range of symptoms. Some infected people may have mild diarrhea or no symptoms at all. Most cases develop severe diarrhea and abdominal cramps. Blood is often seen in the stool. Usually little or no fever is present. How soon after infection do symptoms appear? The symptoms usually appear about 3 days after exposure, with a range of 1 to 9 days.

How is infection with E. coli O157:H7 diagnosed?

Infection with E. coli O15:H7 can only be diagnosed by a special stool culture that is not performed in many laboratories. Public health authorities have advised doctors and laboratories to consider performing a special stool culture test if they suspect E. coli O157:H7, particularly in people with bloody diarrhea.

What is the treatment for E. coli O157:H7 infection?

Most people recover without antibiotics or other specific treatment in 5 to 10 days. Antibiotics are not generally recommended as they may increase the release of harmful toxins from the bacteria.

What complications can result from infection with E. coli O157:H7?

In some people, particularly children under five years of age, the infection can cause a complication called hemolytic uremic syndrome (HUS). This is a serious disease in which red blood cells are destroyed and the kidneys fail. Transfusions of blood or blood clotting factors as well as kidney dialysis may be necessary. A prolonged hospital stay is often required. Fortunately, most people with HUS recover completely, but it can be fatal.

How can infection with E. coli O157:H7 be prevented?

Cook meat thoroughly.

• Cook all ground beef and hamburger thoroughly.
• Make sure the cooked meat is brown throughout (not pink), and the juices run clear.
• Do not eat undercooked hamburger or other ground beef products.

Avoid unpasteurized foods and beverages.

• Drink only pasteurized milk and milk products.
• Avoid unpasteurized apple cider.

Keep raw meats and their juices away from other foods.

• Use separate cutting boards for raw meats and other foods.
• Use separate shopping bags for raw meats while food shopping.
• Wash counters and cooking tools with hot soapy water before and after preparing raw meats.

Wash your hands often.

• Make sure infected people, especially children, wash their hands carefully with soap and warm running water after using the toilet to reduce the risk of spreading the disease.
• Always thoroughly your wash hands with soap and warm running water before feeding infants, touching food, after using the toilet or changing diapers, and after handling raw meat.
• If you work in a child-care center where you change children's diapers, wash your hands carefully between changing each child's diapers. When using gloves, wash your hands and change gloves between each child.
• If you take care of persons who have an E. coli O157:H7 infection, or persons who have diarrhea, wash your hands after bathing patients, emptying bedpans, changing soiled linen, or otherwise coming in contact with stool.

Should an infected person stay home from work or school?

Casual contact at work or school is unlikely to transmit the infection. However, food handlers and children under the age of 5 who have an E. coli O157:H7 infection should stay home until two stool cultures (obtained two days apart) have tested negative for the bacteria. Food handlers must obtain approval from the Health Department before returning to their regular duties at work.

Last updated August 2008