Tuesday, November 26, 2013

Imagining a world without antibiotics

You've probably read it already; if not, do so.

I'd be long dead without antibiotics: several bouts of pneumonia plus other kid stuff I've forgotten about.

The drugs have been getting more and more resistant, as predicted. McKenna warns about regularly mixing antibiotics in animal feed--I gather it helps the critters grow more quickly. But it obviously speeds up the rate at which bacteria become immune. There are details..

However, the companies which sell antibiotics report that only 13 percent of all product sold were sold under the “performance enhancement,” or growth promotion, label. The rest is for animals who need medicine to prevent and treat illness! Therefore, looking at the total volume of product sold is not meaningful to this debate. Although everyone continues to harp on this 80 percent number, it is important to understand that there are many more livestock in the U.S. than there are people; most are larger and need a larger dose. Also critical to this discussion, the types of antibiotics used in humans are much different than those used in animals.

My main take-away from this (interested) party is the claim that the antibiotics used in humans aren't the same as in animals. It isn't clear if he means people get one penicillin derivative and animals get another: in fact one of the comments claims "In 2010, 70 percent of antibiotics sold for use in food animals were ionophores or tetracyclines."

Another says "Drug use is rarely effective to'compensate' for poor practices. A large percent of ontimicrobials, has been often stated, are ionophores. Ths effect of this class is to push the rumen microbial fermentation over to a more favorable volatile fatty acid ratio, improving the efficiency. Also, some work out of Minnesota suggests that the growth promotion effect in hogs with other antibiotics may be in fact a similar mode of action. Which seems to also be a common thread in the press lately about obseity and gut microbes in humans." Which is related to the "grow more quickly" that I thought common knowledge.

So things are a little more complicated than met the eye.

Butchering isn't a precision job, and some cross-contamination occurs with the gut bacteria. Even if the antibiotic residue is below the allowed value, the bacteria are still there and itching for a little sloppy meat handling. Or fertilizer handling--veggies fertilized with nice organic manure...

The companies' report of 13% may or may not be very useful. For oral antibiotics, what's to keep you from mixing an old batch into the big feed bin after the sick cow gets well? As long as the residues die away by the time you ship, who's to know?

I've thought that "provide for the common defence" applied just as well to epidemics as it does to merely human enemies. (No, the ordinary cold and flu season doesn't qualify; you're on your own. Think Spanish flu or bubonic plague.) Systematically building up antibiotic resistance seems like an activity designed to undermine the security of the state.

That said, I suspect that the next big plagues won't come out of American farms, but out of megacities. People share diseases pretty easily, and in a lot of the world the antibiotics can be a little old (I've heard of donated drugs arriving pre-expired), or will be taken only until the patient feels better. Another recipe for new plagues.

2 comments:

Larry Sheldon said...

Scarier--a world without immunizations.

Assistant Village Idiot said...

We brought pre-expired drugs of all sorts into Romania until about 2000, because they were better than nothing. After that, their standards - and ours- got higher.