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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
anemia or kidney failure, which can lead to
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.
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
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.
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
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
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
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:
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
other conditions with similar symptoms, such as other infectious
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
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
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
Treatment of infection with
E. coli O157:H7 bacteria involves managing
dehydration caused by diarrhea.
develop symptoms of
severe blood or kidney problems, such as
anemia or kidney failure, your treatment may
Most people recover from
E. coli infections in 5 to 10 days without the need for
Antibiotics are not recommended. Tell your doctor if
you think you may have E. coli infection and are taking
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
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
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
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
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.
Current as of:
June 4, 2014
E. Gregory Thompson, MD - Internal Medicine & W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
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