E.coli-0157 the cause of hamburger disease and water contamination-Ask Dr. Paul Library
DEAR DR.PAUL: I heard that hamburger disease and water contamination are caused by E.coli. I read that there are many kinds of it. Which are dangerous? How can they be treated or prevented?
PEDIATRICIAN DR.PAUL Answers: I am glad you asked this question, because as the summer arrives we see more of these infections. The E.coli bacteria are one of many that can cause diarrhea and other problems such as urinary infections.
There are different types of E.coli bacteria. Some cause damage to the intestine and thus symptoms, others cause disease by a toxin or poison they secrete.
Clearly, one of the most dangerous types is E.coli 0157 - the E Coli that has been the cause of the recent tragedy in Walkerton, Ontario.
This particular type of E .coli is found in the intestines of cows and can contaminate ground beef. The infection is contracted by eating ground beef which contains this bacteria. E.coli 0157 can also infect humans if it gets into drinking water or swimming pool water. The infection usually is limited to diarrhea with some blood in it, and severe abdominal pain.
The complication of this infection, which occurs in 2-7% of people (mostly the young or very old), is called Hemolytic Uremic Syndrome(HUS). HUS can occur within a week or two after the initial infection.
In HUS, a toxin called verotoxin made by this bacteria causes the red blood cells to break down, resulting in severe anemia and the need for transfusion. This toxin also shuts down the kidneys causing kidney failure which in many cases requires dialysis.
I remember when I was a medical student in the early 1980's, I saw children with HUS, and we really did not know the cause. With time, research discovered that E.coli 0157 was the culprit.
Unfortunately, HUS has a mortality rate of close to 5%. Among the survivors there can be a high rate of long term complications. Antibiotics do not help, and recently there have been some studies on a medication given to people that have the infection which tries to absorb the toxin before it causes damage. The studies are ongoing and so far inconclusive. A stool test can easily confirm that a person is infected with this particular bacteria, for which there really is no specific treatment. Prevention of this infection is our best defense.
Here are some ways to prevent E.coli 0157 infection:
- Make sure hamburger (ground beef) meat is well cooked - gray is not enough; The temperature of the meat should be 70 degrees(Celsius).
- Be careful not to put cooked burgers on the same plate as the raw (uncooked) burgers.
- Make sure that frozen hamburgers are well cooked (they tend to need longer cooking times)
- Make sure that drinking water and water you swim in is chlorinated and properly monitored.
- If a child has the infection, make sure you prevent its spread by very thorough hand washing.
- Avoid unpasteurized juices and raw milk.
- Wash uncooked fresh foods thoroughly.
- Clean and disinfect all cooking surfaces after use.
- And finally, always practise good personal hygiene (handwashing. etc).