Good Germs, Bad Germs

Scientists probe how some microbes keep us healthy in an increasingly antibiotic resistant world.


| November-December 2001



Any woman who has ever done battle with a urinary tract infection will vouch for the notion that the human body can harbor both good germs and bad germs. Bad bacteria in the bladder can turn life into a series of miserable trips to the bathroom. But at the same time, good bacteria can keep yeast that lives harmlessly in the vagina in check. Unfortunately, antibiotics don’t discriminate, so women who take these bacteria-killing drugs often trade a bladder infection for a nasty yeast infection.

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As raw as that deal sounds, it may be the least of our problems when it comes to the downside of the battle against disease-causing germs. In our fervor to stamp out infectious disease, we may be creating new health threats by tampering with the microbe-laden ecosystems in our bodies and in our environment. So says science writer Gary Hamilton in the British environmental journal The Ecologist Report (June 2001).

“Our sense of germs is highly biased,” he writes. “We see how they make us sick but not how they keep us healthy. We view infection as synonymous with disease when it’s not—if it were, we’d all be dead. Thus, in fighting a no-holds-barred war on germs, we may be making a big mistake.”

To understand how this bias can blind us to the complex dynamic between germs and health, consider the case of Helicobacter pylori. In the early 1980s, this spiral-shaped bacterium replaced stress and bad diet as the major suspected cause of stomach ulcers. But, as drug companies rushed to find ways to rid the body of H. pylori, that theory began to unravel. The bacteria seemed much more ubiquitous than first thought, making the ulcer link less certain.

“This doesn’t rule out a link between the germ and disease,” Hamilton writes. “It does, however, suggest a more complex relationship. . . . The more one scans the roster of infectious disease, the more one sees similar murkiness in what we like to view as a straightforward cause-and-effect relationship.”

Rather than view all germs as bad, some scientists are looking more closely at the symbiotic relationships between the human body and various bacteria, fungi, viruses, and protozoa. We have a lot to learn about how the body manages to tolerate and even benefit from these live-in microbes. “After all, many of the germs invading the body are closely related to known pathogens in the environment, and many trigger an immune response when they inadvertently move from one part of the body to another,” Hamilton writes.