…About Antibiotic Resistance.
"You and your favorite cheese—whether it's cheddar, Wensleydale, or a good aged goat brie—have something in common: You're both home to a constantly evolving menagerie of microbes. The bacteria inside you and your fermented dairy live together in a community called a biome, growing and changing in response to their environments. And they adapt to their homes—a cow's hide, a chunk of Swiss, or your gut—by stealing their neighbors' genes.
That genetic transfer has the ability to dramatically change a microbe. "You take this whole gene that you didn't have before, that has totally new functions that you've never had, and you just plop it into this bacterium and suddenly it can do this completely new and different thing," says Miriam Barlow, an antimicrobial resistance researcher at UC Merced. In humans, that's how antibiotic resistance can emerge—one bug evolves a mutation that helps it survive the onslaught of a drug, and it makes its way into the rest of the community. But to fully understand how resistance evolves, studying superbugs isn't enough: You need large, diverse bacterial boroughs to understand how bugs siphon off new genes.
The search for lively bacterial communities led Rachel Dutton, a microbiologist at UC San Diego, to cave-aged cheese wheels—the kind you can only pick up with both hands. She wanted to find an environment that would kill some bacteria, but let other interesting microbes survive. Microbes don't love cheese like humans do—it's acidic, salty, and dry for their tastes—but it's passable housing for some. If surviving antibiotics is like winning the lottery for a bacterium, inhabiting gruyere is like winning at bingo. "We have basically, in our freezer in lab, a few hundred vials of cheese," Dutton says.
That frozen cheese stockpile—which came from 10 different countries—provides plenty of microbes to survey. Dutton and her students isolate bacteria from a smidge of cheese rind, grow communities in petri dishes, then send samples off for genetic sequencing. "Each of these sequences is about four to five megabases, in other words, about 4 million A's, T's, G's and C's," says Kevin Bonham, a postdoc in Dutton's group. Bonham wrote code that lines up hundreds of bacterial species' genomes, plucks out each of their genes, and finds similarities between samples…"