E. coli (Escherichia coli) is the name of a germ, or bacterium, that lives in the digestive tracts of humans and animals.
There are many types of E. coli, and most of them are harmless. But some can cause bloody diarrhea. Some strains of E. coli bacteria (such as a strain called O157:H7) may also cause severe anemia or kidney failure, which can lead to death.
Other strains of E. coli can cause urinary tract infections or other infections.
You get an E. coli infection by coming into contact with the feces, or stool, of humans or animals. This can happen when you drink water or eat food that has been contaminated by feces.
E. coli can get into meat during processing. If the infected meat is not cooked to 160°F (71°C), the bacteria can survive and infect you when you eat the meat. This is the most common way people in the United States become infected with E. coli. Any food that has been in contact with raw meat can also become infected.
Other foods that can be infected with E. coli include:
Human or animal feces infected with E. coli sometimes get into lakes, pools, and water supplies. People can become infected when a contaminated city or town water supply has not been properly treated with chlorine or when people accidentally swallow contaminated water while swimming in a lake, pool, or irrigation canal.
The bacteria can also spread from one person to another, usually when an infected person does not wash his or her hands well after a bowel movement. E. coli can spread from an infected person's hands to other people or to objects.
The main symptoms of an E. coli O157:H7 infection are:
Some people do not notice any symptoms. Children are more likely than adults to have symptoms. Symptoms usually start 3 or 4 days after you come in contact with the E. coli.
Most people get better in about a week. They often don't see a doctor and don't know that E. coli caused their problems.
When E. coli causes serious problems with the blood or kidneys, symptoms include:
Your doctor may suspect that you have an E. coli infection after he or she asks you questions and does an exam. Your stool will probably be tested for E. coli.
E. coli infection usually goes away on its own. Your main treatment is to make yourself comfortable and drink sips of water. Diarrhea causes the body to lose more water than usual. This can lead to dehydration, which is especially dangerous for babies and older adults. Taking frequent, small sips of water will help prevent dehydration.
If you have bloody diarrhea that may be from an E. coli infection, do not take diarrhea medicine or antibiotics. These medicines can slow down the digestion process, allowing more time for your body to absorb the poisons made by the E. coli. Call your doctor instead.
In some people, E. coli infection causes serious problems with the blood and kidneys. These people may need blood transfusions or dialysis. Dialysis is a treatment that helps filter waste products from the blood when the kidneys aren't working right.
Food and water that are infected with E. coli germs look and smell normal. But there are some things you can do to prevent infection:
Learning about E. coli infection:
Children are more likely than adults to develop symptoms of E. coli O157:H7 infection. Most people with the infection will have:
Some people who are infected with the bacteria do not notice any symptoms. They may spread the bacteria to others without knowing it.
There are many conditions with symptoms similar to those of E. coli intestinal infection. Diagnosis of E. coli infection can be complicated by the fact that most bacterial infections that cause diarrhea are accompanied by a high fever. If you have no fever or only a mild fever, your doctor may suspect that something other than bacteria is causing your symptoms.
Bloody diarrhea is common in confirmed cases of E. coli intestinal infection, but the bacteria also should be considered a possible cause of non-bloody diarrhea.
For more information on when to call a doctor about non-bloody diarrhea, see:
Symptoms of E. coli infection usually end in about a week with no further problems. But severe blood and kidney problems may occur within 2 weeks after the onset of diarrhea. These problems can cause kidney failure and sometimes long-term disability or death in some children and older adults.
The medical evaluation for diarrhea that may be caused by E. coli O157:H7 bacteria usually starts with a physical examination and a medical history.
During the medical history, your doctor will ask questions about your symptoms, such as:
Infection with E. coli is easily mistaken for other conditions with similar symptoms, such as other infectious diseases.
A doctor may suspect you have E. coli infection if you have been exposed to the bacteria. During the medical history, your doctor may ask if you have:
During the physical examination, a doctor will usually:
Doctors who suspect E. coli infection will order a type of stool culture that detects strains of E. coli. Because the bacteria can leave the body in only a few days, the sample should be obtained as soon as possible after symptoms appear.
Other tests are sometimes used when the diagnosis is unclear, but these are not yet widely available.
If a child or older adult is diagnosed with E. coli infection, he or she may be watched for development of severe blood or kidney problems. Monitoring requires blood and urine tests to measure essential elements of blood and body fluids.
Treatment of infection with E. coli O157:H7 bacteria involves managing complications—mainly dehydration caused by diarrhea.
Most people recover from E. coli infections in 5 to 10 days without the need for medicine. Antibiotics are not recommended. Tell your doctor if you think you may have E. coli infection and are taking antibiotics.
Nonprescription or prescription diarrhea medicines usually are not used to treat E. coli infection. Many antidiarrheal products slow the rate at which food and waste products move through the intestines. This may allow more time for the body to absorb the poisons produced by the bacteria, increasing the risk of complications such as severe blood and kidney problems.
Avoid these nonprescription products if you have or suspect you have an E. coli infection:
Prescription diarrhea medicines may be harmful when given to a person with E. coli infection. A doctor may prescribe one of these medicines if he or she does not know that E. coli caused the diarrhea. Be sure to discuss your symptoms with your doctor. Sharing information is important to get the proper diagnosis of your condition.
Avoid these prescription medicines if you have or think you may have an E. coli infection:
Home treatment of infection with E. coli O157:H7 bacteria consists of keeping yourself comfortable and preventing the spread of the bacteria. If you aren't infected, take steps to prevent infection.
If you think that you or someone in your care may be infected with E. coli, contact a doctor immediately. Do not treat diarrhea symptoms with any nonprescription or prescription medicines.
Especially in children and adults age 65 and older, watch for symptoms of severe blood and kidney problems, such as fever, weakness, pale skin, or passing small amounts of urine. If any of these symptoms develop, see a doctor immediately.
Other Works Consulted
- American Academy of Pediatrics (2009). Escherichia coli diarrhea (including hemolytic-uremic syndrome). In LK Pickering et al., eds., Red Book: 2009 Report of the Committee on Infectious Diseases, 28th ed., pp. 294–298. Elk Grove Village, IL: American Academy of Pediatrics.
- American Public Health Association (2008). Diarrhea, acute. In DL Heymann, ed., Control of Communicable Diseases Manual, 19th ed., pp. 179–195. Washington, DC: American Public Health Association.
- Donnenberg MS (2010). Escherichia section of Enterobacteriaceae. In GL Mandell et al., eds., Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 7th ed., vol. 2, pp. 2820–2826. Philadelphia: Churchill Livingstone Elsevier.
- Donnenberg MS (2010). Infections due to Escherichia coli and other enteric Gram-negative bacilli. In EG Nabel, ed., ACP Medicine, section 7, chap. 8. Hamilton, ON: BC Decker.
- Procop GW, Cockerill F III (2001). Enteritis caused by Escherichia coli and Shigella and Salmonella species. In WR Wilson et al., eds., Current Diagnosis and Treatment in Infectious Diseases, pp. 548–556. New York: McGraw-Hill.
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
Current as ofSeptember 9, 2014
Current as of: September 9, 2014
To learn more, visit Healthwise.org
© 1995-2014 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.