Not all E. coli is bad E. coli: E. coli gets bad press, but it has beneficial uses

Q.

I have heard in the press about all these E. coli epidemics and have heard that E. coli is pretty dangerous. But I have also heard that E. coli is found in everyone's intestines.

My daughter had a urinary tract infection with E. coli, her pediatrician was not that concerned and it was easily treated with antibiotics. How can all this be so; that E. coli can be extremely dangerous, or just a mild infection or just nothing at all?

A.

We are all ecosystems.

We have a large number of bacteria, and a few other things such as yeast, just hanging around.

Certainly, there is some give and take. For example, some bacteria make vitamin K for us, which helps in blood clotting. Mostly, they seem like mysterious co-travelers.

Mostly, organisms hang out in two different places: the large intestine (colon); or the upper airway (nose, mouth, throat, sinuses).

Generally, these are places where no harm is done. But there are bacteria in all of us that could kill us if they ended up in the wrong area.

Sometimes the bacteria, taking advantage of a breakdown in our defenses, grow in parts of our body that they shouldn't.

An example is a burst appendix.

There are showers of bacteria that get into the abdomen outside of the intestine. These are the same normal bacteria that live in our gut every day.

Escherichia coli is a universal organism in humans - and in nearly all mammalian species.

E. coli is so common that we know more about it than any other organism.

Long before we broke the genetic code in humans, we knew the code of E. coli.

E. coli is now used to produce medicines by coaxing the bacteria to produce proteins.

This leads to such drugs such as insulin, growth hormones and factor VIII for hemophiliacs.

So what about the "bad" E. coli?

It often is said that the clothes make the man. I suppose that is true for E .coli as well.

They don't wear clothes, but they do wear antigens, or substances that differentiate a particular E. coli strain.

There are many different "O" antigens (several hundred, in fact), and several different "H" antigens.

The nasty E. coli that has contaminated spinach and beef is called E. coli O157:H7.

You don't find it just anywhere, and you don't find it in healthy people.

Among the animals you do find it in are asymptomatic cattle, although the exact percentage of cattle that have the bacteria is debatable.

E. coli O157:H7 can cause bloody diarrhea, fever and all sorts of neurological conditions in infected people, as well as the rare but nasty illness called hemolytic uremic syndrome, or HUS.

HUS usually is found in children and affects the way blood clots (or unclots) and can be fatal.

The urinary tract infections are one of those "wrong place" infections.

The bladder is usually a pretty good barrier at preventing the spread of infection.

Occasionally, the bladder will get overwhelmed, but this is uncommon in kids who do not have renal system anomalies or immune problems.

Another interesting use of bacteria is in promoting health.

We know that during gastrointestinal illness, giving certain live bacteria help the symptoms.

For example, the easiest way to do this is to feed sick kids yogurt, which is a culture of a bacteria called Lactobacillus.

Acidophilus or Bifidobacteria are two other types of bacteria that may help as well.

We also know that your normal ecosystem can get knocked out of whack by antibiotic use as well.

Using these substances may help alleviate some of the intestinal side effects.

There is a lot more to tell about the intricacies of our bodies and their relationship to microorganisms.

When you see your son or daughter tonight, why not give him or her a big hug and say, "My sweet child, you are my favorite ecosystem."

(5/13/07)

Dr. Norton's column appears on the second Monday of each month in the Milwaukee Journal Sentinel and is reposted here. Contact Dr. Norton by phone at (414) 228-4800 or via e-mail.

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