Scientists probe how some microbes keep us healthy in an increasingly antibiotic resistant world.
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.
Still, evidence abounds that certain germs can indeed be helpful. Bacteria in the mouth may cause tooth decay but can also inhibit strep throat and pneumonia. Rats fed on a diet that promoted the growth of lactobacilli in the small intestine appear to be more resistant to food poisoning. And studies have found that children who grow up in large families or attend day care early—and are thus exposed to more germs—are less likely to develop allergies later in life.
Though no one really knows how to define and promote the proper balance between good and bad germs, Hamilton and others argue that at the very least it’s time to reassess our zeal to wipe out the bad ones. As noted on the Web site for the Alliance for the Prudent Use of Antibiotics (http:// www.healthsci.tufts.edu/apua/Ecology/EIA.html), the indiscriminate use of antibiotics can lead to drug-resistant germs that are hard to treat.
But, as Hamilton points out, all one need do is walk down the soap aisle in the grocery story to see that the battle against germs is no longer confined to research labs and hospitals. It’s become a marketing niche. Nearly every cleaning product now comes with an antibacterial formula and an aggressive advertising campaign.
At the same time, there are signs that we are starting to make peace with germs. Researchers have begun to talk about “probiotics”—the use of bacteria to treat and prevent illness. For example, scientists reported in August that a newly discovered, harmless virus called Hepatitis G somehow appears to slow the rapidly duplicating AIDS virus. And, Hamilton writes, a new spray containing indigenous chicken flora may render baby chicks salmonella-proof.
“Clearly, western medicine is approaching a crossroads in the quest to save more lives from infectious disease. The growing problem of antibiotic resistance and the emergence of new microbal threats had raised the call for new action,” Hamilton writes. “One response would be to intensify the war on germs still further. Another would be to accept the reality of where we stand.”
“We are not living in a bubble,” Tufts University scientist Stuart Levy told Hamilton. “We’ve emerged and evolved in the bacterial world and to try to get rid of bacteria is to try to get rid of the world.”
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