Escherichia Coli

Gastroenteritis caused by Escherichia Coli, Traveler's Diarrhea

What is Escherichia coli?

Escherichia coli is a bacterium normally found in the human digestive tract that is associated with various diseases. Although usually not a problem, under certain conditions, E. coli can cause an infection of the gastrointestinal tract resulting in gastroenteritis (inflammation of the stomach and intestine). It can also be the cause of certain types of pneumonia and urinary tract infections.

The various diseases caused by E. coli are due to several different strains of the bacteria (enteropathogenic, enterotoxigenic, enteroinvasive, enteroadherent, and enterohemorrhagic).

How is it diagnosed?

History: Symptoms of gastroenteritis caused by E. coli include abdominal cramps, loss of appetite, nausea and vomiting, diarrhea, and decreased energy. Pneumonia symptoms include chills, fever, chest pain, cough, and purulent (pus) or bloody sputum. Urinary tract infections usually involve pain or burning with urination.

Physical exam: In gastroenteritis caused by E. coli, the physical exam may reveal fever, abdominal tenderness, drowsiness, decreased blood pressure, or increased heart rate. Individual may have signs of dehydration including orthostatic blood pressure (blood pressure that changes with body position changes), dry mucous membranes, sunken eyes, and decreased skin tension (turgor). Individuals with pneumonia may present with fever and chest congestion. Urinary tract infections can cause lower abdominal tenderness and fever.

Tests for gastroenteritis include examination of the stool for white blood cells, and a stool culture to identify the E. coli organism. In cases of suspected pneumonia, a sputum culture is done to identify the E. coli organism. A culture may also be done on the blood or pleural fluid. A chest x-ray identifies areas of patchy infiltrates or accumulated fluid (pleural effusion). Although a urinalysis indicates a urinary tract infection, a culture of the urine is necessary to identify the E. coli organism and confirm the diagnosis.

How is it treated?

Treatment is related to the particular disease. Although gastroenteritis caused by Escherichia Coli is usually self-limited, replacement of fluid and electrolytes lost through vomiting or diarrhea is essential. These may need to be administered intravenously to prevent dehydration.


Antibiotics may be used if the condition warrants. Antibiotic therapy is usually effective against Escherichia Coli infections resulting in pneumonia or urinary tract infections.

Information Brand Generic Label Rating Zithromax Azithromycin On-Label
Cipro Cipro Ciprofloxacin On-Label Amoxil Amoxicillin On-Label
Minocycline 100 mg Minocin Minocycline On-Label Augmentin Amoxicillin/Clavulanate Off-Label
Ampicillin tablets Principen Ampicillin Off-Label

Imodium (Loperamide), Noroxin (Norfloxacin), Doryx (Doxycycline)

What might complicate it?

Complications can include septicemia (a life threatening condition), severe dehydration, or hemolytic uremic syndrome (HUS) in children.

Predicted outcome

Gastrointestinal diseases caused by Escherichia Coli are usually self-limited. Antibiotic therapy may shorten the course of illness. Most individuals recover within seven to ten days. If illness persists longer than ten days, further evaluation needs to be done to rule out parasites, other treatable pathogens, or noninfectious causes. Pneumonia and urinary tract infections caused by E. coli usually respond satisfactorily to appropriate antibiotic therapy.


Conditions with similar symptoms include ischemic colitis, other forms of gastroenteritis, and other infectious causes resulting in urinary tract infections or pneumonia.

Appropriate specialists

Internist, gastroenterologist and hematologist.

Last updated 17 December 2015

