Michael Specter has a piece in The New Yorker this week about whether bacteria, in addition to doing us harm, may also be helpful and even necessary for our survival. (It's behind a paywall, but if you don't subscribe to The New Yorker, you should.)
Specter begins with the story of the Nobel-Prize-winning discovery that the bacterium H. pylori is the principal cause of gastric and peptic ulcers, and that it is associated with an increased risk of stomach cancer. He also notes that the bacterium has been colonizing humans for 200,000 years. And then he quotes a researcher who wondered "how an organism as old as humans could survive if it caused nothing but harm."
Specter then pulls back from the narrative to tell us things we need to know before he can continue the story. "Since 1953, when James Watson and Francis Crick described the structure of DNA, we have looked upon our genes as our biological destiny…" It's a standard technique for breaking a narrative into pieces, and Specter uses it well–if too often. A column-and-a-half later, he gets back to the opening anecdote, adds a bit, and then pulls back again. "Bacteria have inhabited the earth for at least two-and-a-half billion years…"
Specter's piece is a fair wrap-up of what's known about the human microbiome, as researchers call the collection of microbes that live on and in the human body. It doesn't contain much that will be new to readers who've read two or three such articles, but it will undoubtedly be news to many readers.
Specter recaps what's known about the potential harm from antibiotics, which were among the titanic achievements of 20th century medicine. Now, however, evidence is accumulating that the disturbances that antibiotics create in the human gut could increase the risk of human obesity. To make the point, Specter reminds us that farm animals are dosed with antibiotics not to prevent infections but to speed their growth. If antibiotics make animals fatter, doesn't it seem plausible they would do the same to us?
And he has a nice analogy that I hadn't read before–maybe it's original with him:
Each of us seems more like a farm than like an individual assembled from a rulebook of genetic instructions. Medicine becomes a matter of cultivation, as if our bacterial cells were crops in a field.
Isn't that nice?
Specter ties things together nicely, and if you haven't read much about the human microbiome, this piece is a good place to start.
-Paul Raeburn
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