I just read the most fascinating book. If you happen to like biology and history of science, which I do.
Apparently a lot has been learned since I took AP Biology in high school (and, just to date me, one of my most vivid memories of that class is my teacher flipping on the television because the Challenger had just blown up). Meaning, we never learned about molecular phylogeny or horizontal gene transfer in the caveman days; nor am I going to explain those things in a blog post. But I did double-check with my own 17-year-old who just took his AP Biology class, and I'm happy to report my taxpayer dollars were at work. With a few probing questions I discovered he had learned about these new-to-me concepts. Knowledge marches on.
Anywho. The reason I do bring all that up here is that (1) it was an awesome book, which I highly recomment, and (2) the author David Quammen did touch on antibiotic use in the meat industry.
As you probably know, antibiotic use is widespread in Big Meat not because the cows and such are always coming down with pneumonia, but rather because folks noticed it helps the livestock gain weight faster. And faster weight gain equals less time to market equals cheaper meat for us consumers.
As you probably also know, the world has a growing problem with antibiotic-resistant microbes, which the widespread application of antibiotics to industrial livestock only makes worse by leaps and bounds. In the caveman days (i.e., when I learned biology), we thought this was because of straightforward Darwinian natural selection: you hit the wee bugs with the antibiotics, and whatever survived lived to reproduce another day, and after awhile that was all that you were left with, the survivors.
It turns out the wee bugs have much faster-working crafty methods. As Quammen explains,
resistance to multiple antibiotics among bacteria spreads horizontally. It can happen by conjugation. It can happen by transduction. It can happen in a sudden leap. Consequently, it has become a dire problem. And the problem is especially severe in hospitals, where such huge volumes and such variety of antibiotics are used, selecting for resistant bacterial strains that then infect people who are already ill.
I had no idea before I read The Tangled Tree that resistance was a problem as early as 1955, when penicillin had been in use only from 1942 onward, or that MRSA emerged as a worldwide concern by 1972! And I had no idea that resistance could spread so rapidly through so many avenues, making natural selection look poky and harmless by comparison.
Quammen blames the overuse of antibiotics on patients and on livestock. I can't help your hypochondria (except to urge you to let your healthy microbiota flourish as much as you can, rather than wiping it out with antibiotics unless you absolutely must), but I can encourage you to buy meat not produced by relying on antibiotics.
Globally, total consumption of antimicrobials (that is, drugs against dangerous microbial fungi as well as bacteria) by livestock was roughly 126 million pounds, with China using even more than the United States, and Brazil in third place. Most of that total goes into cattle, chickens, and pigs. A significant fraction of it involves drugs that are also important in human medicine.
...So there's an extraordinary amount of evolutionary pressure, out there in the world, forcing bacteria to acquire resistance or die. But the most startling aspects of the trend have been how speedily resistance has spread and how many different kinds of bacteria have acquired multiple resistance--that is, resistance not just to one antibiotic but also to whole arsenals of different kinds.
In addition to rapid spread of multiple resistance, Quammen discusses a study published in the New England Journal of Medicine about the spread of resistance from the bacteria in chicken guts to human guts:
...[The] intestinal bacteria of chickens, if the birds ate tetracycline-laced feed, acquired resistance to the antibiotic within a week. Less expected, more worrying, was that the bacteria in the bowels of farm workers on the same site acquired the same resistance over a period of months.
How? It's complicated. Meaning, do read the book.
Now, meat raised without antibiotics is more expensive. Of course, because it takes longer to raise. But I think most of us eat more meat than we need to, and once my teenage boy heads off to college, I plan on reducing the meat the rest of us consume significantly. If we reduce overall meat consumption, then the meat we do eat can be better meat. Pastured. Raised without antibiotics.
Ask our Market farmers how they raise theirs this week. And grab some vegetables, while you're at it. This book didn't mention it, but other gut books have: the best way to keep nasty bugs from taking hold in your gut is to keep all the good bacteria prosperous, numerous and healthy. And that takes lots of vegetables and fiber.
Oh, and try not to touch anything or have any open wounds the next time you're in a hospital.