Wearable Bacteria, Fecal Enemas, and Matching Lesbians

The NIH sets out to study the human body's resident bacteria.

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Scientists know some interesting facts about the microbes we wear on—and in—our bodies. And as of today, they're poised to learn a lot more.

They know, for example, that healthy skin is crawling with dozens of varieties of bacteria. On any given day, the left and right sides of a person tend to carry the same species, but the species she's covered in today may be very different from the ones she'll be wearing a few months from now.

They also know we each have far more bacteria living inside us than we have cells in our body. Intestinal bacteria have been estimated to exceed human cells by a factor of 10, and most of them aren't bad. In fact, people can get quite sick when their normal intestinal "flora" die. Some people with diarrhea-inducing imbalances in their colonic ecosystems have gotten better after doctors inserted a healthy person's fecal matter into their anuses. Gross but true. And approximately one in three people carries Staphylococcus aureus in his or her nose. That pathogen is nothing to sniff at: The antibiotic-resistant form known as MRSA is a growing threat to otherwise healthy people, and a recent study of European veterinarians found that 12.5 percent of them were unknowingly carrying that dangerous strain.

Then there's this fact about lesbian couples: In sickness and in health, partners appear to share similar sets of vaginal bacteria. All women have numerous kinds of bacteria living in their vaginal secretions, and each woman seems to have her own slightly unique set. If a woman's bacterial community becomes imbalanced, she can develop a condition called bacterial vaginosis. And if one lesbian in a monogamous couple has BV, her partner is many times more likely than normal to have it as well, suggesting that one can transmit her imbalanced vaginal ecosystem to the other.

But those fun facts aren't enough to satisfy microbiologists, it seems. They want to know more about the bugs that live on our skin, in our intestines and noses, and in—as a government press release put it today—"the female urogenital tract." These, along with the mouth, are the regions of the body that the National Institutes of Health will pay scientists to explore as part of a new research effort called the Human Microbiome Project.

The NIH announced today that it will grant scientists a total of $115 million in taxpayer money over the next five years to decode the genomes of hundreds of microbes that live in or on the human body. Some of the bugs may be associated with BV, diarrhea, or perhaps even skin disorders like eczema. Others will be harmless—or even helpful—residents of our bodies.

The project's purpose is not to provide bloggers with fodder for holiday cocktail parties, though it may do that too. According to the press release, which quotes NIH Director Elias Zerhouni: "It is essential that we understand how microorganisms interact with the human body to affect health and disease. This project has the potential to transform the ways we understand human health."

Update 12/20/07, 12 p.m.: Thanks to Monado at Science Notes, I just noticed a fascinating new post on Aetiology that says more than you might want to know about fecal matter transplants.