E. coli O157:H7

Definition

E. coli O157:H7 is a highly virulent strain of the Escherichia coli bacterium that is a leading cause of foodborne illness and can lead to severe gastrointestinal complications. This pathogenic strain is known for its ability to produce Shiga toxin, a potent toxin that damages the lining of the intestines and can lead to life-threatening complications.

5 Must Know Facts For Your Next Test

1. E. coli O157:H7 is primarily transmitted through the consumption of contaminated food or water, with undercooked ground beef, unpasteurized dairy products, and contaminated produce being common sources of infection.
2. Symptoms of E. coli O157:H7 infection typically include severe abdominal cramps, watery diarrhea that may become bloody, and in some cases, vomiting.
3. The Shiga toxin produced by E. coli O157:H7 can cause damage to the lining of the intestines, leading to the development of hemorrhagic colitis, a condition characterized by severe bloody diarrhea.
4. Hemolytic uremic syndrome (HUS) is a life-threatening complication of E. coli O157:H7 infection, occurring in 5-15% of cases, and can lead to kidney failure, neurological issues, and even death.
5. Proper food handling, thorough cooking of meat, and good hygiene practices are essential in preventing E. coli O157:H7 infections, as this pathogen can survive in the environment and on surfaces for extended periods.

Review Questions

• Describe the key virulence factors of E. coli O157:H7 that contribute to its ability to cause severe gastrointestinal illness.
  • The primary virulence factor of E. coli O157:H7 is its ability to produce Shiga toxin, a potent cytotoxin that damages the lining of the intestines. This toxin can lead to the development of hemorrhagic colitis, characterized by severe bloody diarrhea. Additionally, E. coli O157:H7 can adhere to the intestinal epithelium and disrupt normal intestinal function, further contributing to the severe gastrointestinal symptoms associated with this pathogen.
• Explain the potential complications that can arise from an E. coli O157:H7 infection and discuss the mechanisms by which these complications develop.
  • The most serious complication of E. coli O157:H7 infection is the development of hemolytic uremic syndrome (HUS). HUS occurs when the Shiga toxin produced by the bacteria damages the lining of blood vessels, leading to the destruction of red blood cells and the formation of blood clots. These clots can then obstruct the kidneys, causing renal failure. Additionally, the Shiga toxin can also affect the central nervous system, leading to neurological complications. The severe nature of these complications underscores the importance of prompt recognition and appropriate medical treatment for E. coli O157:H7 infections.
• Evaluate the public health measures and preventive strategies that can be implemented to reduce the incidence of E. coli O157:H7 infections in the community.
  • Preventing E. coli O157:H7 infections requires a multifaceted approach involving both individual and community-level interventions. At the individual level, proper food handling, thorough cooking of meat, and good hygiene practices are crucial in reducing the risk of exposure. At the community level, public health authorities can implement measures such as strengthening food safety regulations, improving surveillance and outbreak detection, and educating the public on the importance of safe food preparation and handling. Additionally, research into the development of effective vaccines or alternative treatment strategies could significantly contribute to the prevention and control of E. coli O157:H7 infections, which remain a significant public health concern.

Related terms

Shiga Toxin: A powerful cytotoxin produced by E. coli O157:H7 and other Shiga-toxin producing E. coli strains that can cause severe damage to the intestinal lining and lead to potentially fatal conditions like hemolytic uremic syndrome.

Hemolytic Uremic Syndrome (HUS): A serious and potentially life-threatening complication of E. coli O157:H7 infection characterized by the destruction of red blood cells, kidney failure, and neurological issues.

Enterohemorrhagic E. coli (EHEC): A group of pathogenic E. coli strains, including O157:H7, that produce Shiga toxin and can cause severe bloody diarrhea and hemorrhagic colitis.