Escherichia coli (E. coli)
|Common Name(s)||E. coli|
|Scientific Name(s)||Escherichia coli O157:H7|
|Physical Attributes||Gram-negative rod-shaped bacterium producing Shiga toxins|
|Mode(s) of Transmission||Contaminated, undercooked meat and leafy vegetables; person-to-person contact; drinking or swimming in contaminated water|
|Likely BW Form(s)||Aerosol; water contamination|
|Pathology||Severe bloody diarrhea and abdominal cramps; small percentage leads to complication called hemolytic uremic syndrome (HUS), in which the red blood cells are destroyed and the kidneys fail|
|Vector/Dormant Form||Intestine of healthy cattle, deer, goats, sheep, humans|
|Incubation Period||2-8 days|
|Fatality||Low; hemolytic uremic syndrome (HUS): 3%-5% with intensive care|
|Treatment||None; antibiotics and antidiarrheal agents should be avoided|
Escherichia coli O157:H7 is a leading cause of foodborne illness. Based on a 1999 estimate, 73,000 cases of infection and 61 deaths occur in the United States each year. E. coli O157:H7 is one of hundreds of strains of the bacterium Escherichia coli. Although most strains are harmless, this strain produces a powerful toxin that can cause severe illness. E. coli O157:H7 has been found in the intestines of healthy cattle, deer, goats, and sheep.
Infection with E. coli often leads to bloody diarrhea, and occasionally to kidney failure. People generally become ill from E. coli O157:H7 two to eight days (average of 3-4) after being exposed to the bacteria. Escherichia coli O157:H7 infection often causes severe bloody diarrhea and abdominal cramps. Sometimes the infection causes non-bloody diarrhea or no symptoms. Usually little or no fever is present, and the illness resolves in 5 to 10 days.
In some persons, particularly children under 5 years of age and the elderly, the infection can also cause a complication called hemolytic uremic syndrome (HUS), in which the red blood cells are destroyed and the kidneys fail. Strokes may result. About 8% of persons whose diarrheal illness is severe enough that they seek medical care develop this complication. In the United States, HUS is the principal cause of acute kidney failure in children, and most cases of HUS are caused by E. coli O157:H7.
People can become infected with E.coli O157:H7 in a variety of ways. Though most illness has been associated with eating undercooked, contaminated ground beef, people have also become ill from eating contaminated bean sprouts or fresh leafy vegetables such as lettuce and spinach. Person-to-person contact in families and child care centers is also a known mode of transmission. In addition, infection can occur after drinking raw milk and after swimming in or drinking sewage-contaminated water.
Most people recover without antibiotics or other specific treatment within 5 to 10 days. Antibiotics should not be used to treat this infection. There is no evidence that antibiotics improve the course of disease, and it is thought that treatment with some antibiotics could lead to kidney complications. Antidiarrheal agents, such as loperamide (Imodium®), should also be avoided.
In some people, E. coli O157:H7 infection can cause a complication called hemolytic uremic syndrome (HUS), a life-threatening condition that is usually treated in an intensive care unit. Blood transfusions and kidney dialysis are often required. With intensive care, the death rate for hemolytic uremic syndrome is 3%-5%.
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