E. coli — friend or foe?

Philip J. Goscienski, M.D.

May 2010

E. coli is a bacterium with a horrible reputation but each of us is carrying around a few ounces of it in our intestinal tract without suffering any ill effects. It's part of a large family of germs and like any family most members are quite benign, a few get into occasional trouble and some are truly black sheep.

The name that we're familiar with because of its sometimes deadly strains is a short version of Escherichia coli. It was named after a German physician, Theodor Escherich. He found it within the human colon late in the 19th century, hence its scientific-sounding but merely descriptive name.

For most mammals, including humans, E. coli is one of the more common germs, part of our normal flora that we not only tolerate but that help us in various ways. Most of the several dozen strains serve as protective barriers to more dangerous germs that occasionally find their way into us via contaminated food. Residing primarily in the large intestine, E. coli produces some of the vitamin K that we require for normal blood clotting.

Disease-producing strains cause their damage in various ways, mostly by producing toxic chemicals that injure the lining of the intestine. As a group, E. coli is the most common cause of traveler's diarrhea. Certain strains are capable of invading the urinary bladder, especially in women. A particular strain, O157:H7, makes headlines from time to time by causing outbreaks of severe illness, often marked by kidney failure.

Undercooked ground beef is one of the most common vehicles for outbreaks of E. coli infections but that's no reason to become a vegetarian. Several kinds of vegetables have been the source of contamination and one of the best-known outbreaks in recent years was due to raw spinach.

It's not likely that we can avoid all infections due to E. coli or other germs such as Salmonella but thorough cooking, especially for ground meat, is a good start. Rare hamburgers are luscious but persons at high risk of serious illness from E. coli such as young infants, elderly persons or those with poor immune systems should avoid them. Leafy, salad-type vegetables that are meant to be eaten raw should be washed thoroughly. Don't take a chance on raw greens at all when you're traveling in countries that are known for traveler's diarrhea. You might encounter a not-so-friendly E. coli.

Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at drphil@stoneagedoc.com.