Escherichia coli O157:H7

Definition

Escherichia coli O157:H7 is a strain of the bacterium E. coli that can cause severe foodborne illness in humans. This pathogen is particularly known for its ability to produce Shiga toxin, which can lead to serious health complications such as hemolytic uremic syndrome (HUS). Understanding this strain is essential due to its significant impact on public health and food safety.

5 Must Know Facts For Your Next Test

1. E. coli O157:H7 is often associated with undercooked ground beef, unpasteurized milk, and contaminated fresh produce.
2. Infection with this bacterium can lead to symptoms like severe abdominal cramps, diarrhea (which may be bloody), and vomiting.
3. This strain of E. coli is particularly dangerous for young children and the elderly, who are more susceptible to severe complications.
4. Preventive measures include proper cooking of meats, washing hands thoroughly, and avoiding cross-contamination in food preparation.
5. Outbreaks of E. coli O157:H7 can lead to significant public health alerts and food recalls due to its potential severity.

Review Questions

• What are the common sources of E. coli O157:H7 infections, and how do these sources contribute to foodborne illnesses?
  • Common sources of E. coli O157:H7 infections include undercooked ground beef, unpasteurized dairy products, and contaminated fruits and vegetables. These sources contribute to foodborne illnesses because the bacteria can easily contaminate food during production or preparation processes. For instance, ground beef can be contaminated if the cattle carry the bacteria in their intestines. When not cooked properly, the bacteria survive and can cause severe gastrointestinal distress in those who consume it.
• Discuss the role of Shiga toxin in the pathogenicity of E. coli O157:H7 and its impact on human health.
  • Shiga toxin plays a crucial role in the pathogenicity of E. coli O157:H7 by damaging the lining of the intestines and disrupting protein synthesis within cells. This toxin can lead to severe health issues, including bloody diarrhea and hemolytic uremic syndrome (HUS), which can result in kidney failure. The presence of Shiga toxin makes this strain particularly dangerous and highlights the need for effective public health measures to prevent outbreaks.
• Evaluate the effectiveness of current preventive measures against E. coli O157:H7 outbreaks in the context of food safety regulations.
  • Current preventive measures against E. coli O157:H7 outbreaks include stringent food safety regulations that mandate proper cooking temperatures for meats, thorough washing of produce, and pasteurization of dairy products. These regulations have proven effective in reducing the incidence of infections; however, challenges remain due to factors like consumer behavior and food supply chain complexities. Continuous education about safe food handling practices is necessary to maintain low infection rates and ensure public health safety.

Related terms

Shiga toxin: A potent toxin produced by certain strains of E. coli, including O157:H7, which can cause severe damage to the intestines and kidneys.

Hemolytic Uremic Syndrome (HUS): A serious condition that can occur as a complication of E. coli O157:H7 infection, characterized by kidney failure, anemia, and low platelet count.

Foodborne illness: Illnesses caused by consuming contaminated food or beverages, often leading to symptoms like nausea, vomiting, diarrhea, and abdominal cramps.