Pathogenic Strain

• Specific strains such as O157:H7 can cause a gastrointestinal illness that may be followed by organ failure, especially the kidneys.
  
  

Onset

• The symptoms of E. coli O157:H7 infections usually begin three to four days after being exposed to the bacteria. However, the onset period can vary from one day to more than a week.
  
  

Course

• An infection of E. coli O157:H7 is usually self-limiting and resolves within about a week in patients with a healthy immune system. However, this strain can be life-threatening in patients with compromised immune systems.
  
  

Progression

• Diarrhea is the most common symptom of E. coli infections. It's typically mild but can become severe and bloody in immunocompromised patients. Additional symptoms include abdominal pain, nausea and vomiting.
  
  

Complications

• Hemolytic uremic syndrome is the most common complication of an E. coli infection. This condition is a form of kidney failure that causes the abnormal breakdown of blood cells in the body.