Escherichia coli O157:H7

Escherichia coli O157:H7 is a strain of the bacterium Escherichia coli (E. coli) that causes severe foodborne illness in humans. This strain is one of the Shiga toxin-producing types of E. coli, or STECs, which are responsible for most E. coli infections in the United States.

Characteristics

E. coli O157:H7 is a Gram-negative, rod-shaped bacterium that is capable of surviving in an environment with or without air (facultative anaerobe). It is distinguished by its ability to produce Shiga toxins, which are responsible for the damage to the lining of the intestine. This damage can lead to bloody diarrhea, a hallmark symptom of E. coli O157:H7 infection.

Transmission

E. coli O157:H7 is most commonly transmitted to humans through contaminated food or water. It can be found in raw or undercooked meat, especially ground beef, as well as in unpasteurized milk and juice. It can also be transmitted through contact with the feces of infected animals or people.

Symptoms and Treatment

Symptoms of E. coli O157:H7 infection typically begin 3-4 days after exposure and include severe stomach cramps, diarrhea (often bloody), and vomiting. Most people recover within a week, but some develop a severe, life-threatening type of kidney failure called hemolytic uremic syndrome (HUS).

Treatment for E. coli O157:H7 infection is primarily supportive, including rest and plenty of fluids. Antibiotics are not typically used, as they can increase the risk of HUS.

Prevention

Prevention of E. coli O157:H7 infection involves proper food handling and preparation, including thorough cooking of meat, avoidance of unpasteurized dairy products and juice, and frequent handwashing.

See Also

• Foodborne illness
• Hemolytic uremic syndrome
• Escherichia coli