Up With Germs!

It's time for a microbes' rights movement.

Too long have we reviled the misunderstood microbe as an evil to be sprayed, slathered or scrubbed away. It is time to say, "Germs, we're sorry."

That is basically what a fascinating new exhibit at the American Museum of Natural History in New York is doing. "The Secret World Inside You" is a paean to the trillions of microbes that live on and in each of us.

Until just recently, says genomic scientist Robert DeSalle, co-curator of the exhibit, most people thought of microbes only in terms of illness. Today researchers are realizing we let a few bad apples influence our outlook. "There are so few bad bacteria in our bodies relative to the good ones that it gives all microbes a bad rap," says DeSalle.

Consider this: Mice bred to have guts completely bereft of bacteria — sterile — "are much happier when you put some microbes into them," DeSalle says. It is normal for us all to be crawling with microscopic critters.

Many of those critters are on display at the museum, magnified a zillion times, and just be glad they're normally microscopic. Attractive, they aren't. But scientists are actually starting to think of them sort of like genes. We each have our own "microbiome" — a set of microbes that lives on and in us. No two people's microbiomes are the same, and our microbiomes change depending on what we eat, where we live and even our age.

Most significantly, they change when we take antibiotics. These kill off a whole lot of microbes, some bad but many good. It can take a long time for them to grow back, and not all of them will. It's sort of like replanting a garden after a nuclear attack. That's why doctors are trying to prescribe antibiotics more sparingly these days.

We're not at all sure what all the different microbes do yet (there can be 100 to 200 different microbial species in your mouth alone), but more and more, scientists are beginning to suspect that they play a big role not just in sickness, body odor and tooth decay — all that bad stuff — but actually in fighting off disease.

You have probably heard by now (if only because it's so weird) of fecal transplants. That is, taking the fecal matter from someone healthy and transplanting it into the gut of someone sick. People suffering from Clostridium difficile infections, an illness of the gastrointestinal tract, have been cured when they received someone else's stool.

How come? Apparently, some of those germs that we're so grossed out by actually conquer the illness. Score one for the germs!

What could be stranger than a fecal transplant? How about the idea that some microbes — or some constellation of them — could be responsible for how we behave?

The exhibit discusses an experiment involving two breeds of mice. The "anxious" breed lingered for several minutes before leaping off a platform to explore a new space. The "impulsive" breed lingered for just a few seconds. When scientists exchanged their gut microbes — just the stuff swishing around in their intestines — guess what. The anxious group jumped off a minute earlier, and the impulsive mice now waited a minute longer.

The mice did not receive new organs or new genes or new training. Just some new germs.

So next time you're reaching for antibacterial goop and it's not because you're about to perform surgery or handle a newborn, remember: Most germs are our friends.

Er ... most microbes are our friends, I mean.

Old habits die hard.

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