Tuesday, July 13, 2010

Microbes and us

Sounds pretty gross. From How Microbes Defend and Define Us.
In 2008, Dr. Khoruts, a gastroenterologist at the University of Minnesota, took on a patient suffering from a vicious gut infection of Clostridium difficile. She was crippled by constant diarrhea, which had left her in a wheelchair wearing diapers. Dr. Khoruts treated her with an assortment of antibiotics, but nothing could stop the bacteria. His patient was wasting away, losing 60 pounds over the course of eight months. “She was just dwindling down the drain, and she probably would have died,” Dr. Khoruts said.

Dr. Khoruts decided his patient needed a transplant. But he didn’t give her a piece of someone else’s intestines, or a stomach, or any other organ. Instead, he gave her some of her husband’s bacteria.

Dr. Khoruts mixed a small sample of her husband’s stool with saline solution and delivered it into her colon. Writing in the Journal of Clinical Gastroenterology last month, Dr. Khoruts and his colleagues reported that her diarrhea vanished in a day. Her Clostridium difficile infection disappeared as well and has not returned since.
But the real point is this.
Scientists are regularly blown away by the complexity, power, and sheer number of microbes that live in our bodies. “We have over 10 times more microbes than human cells in our bodies,” said George Weinstock of Washington University in St. Louis. But the microbiome, as it’s known, remains mostly a mystery. “It’s as if we have these other organs, and yet these are parts of our bodies we know nothing about.” …

A number of teams are working together to tackle this problem in a systematic way. Dr. Weinstock is part of the biggest of these initiatives, known as the Human Microbiome Project. The $150 million initiative was started in 2007 by the National Institutes of Health. The project team is gathering samples from 18 different sites on the bodies of 300 volunteers.

To make sense of the genes that they’re gathering, they are sequencing the entire genomes of some 900 species that have been cultivated in the lab. Before the project, scientists had only sequenced about 20 species in the microbiome. In May, the scientists published details on the first 178 genomes. They discovered 29,693 genes that are unlike any known genes. (The entire human genome contains only around 20,000 protein-coding genes.)

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