Superbugs

Increasing antibiotic resistance in bacteria is a nice demonstration of:

  • The speed and effectiveness of evolutionary change.
  • The Law of Unintended Consequences
  • The danger of hospitals

Antibiotics are in effect poisons that don’t happen to affect humans, typically because they interfere with bacterial cell walls that our cells don’t have. It doesn’t take long in human terms for bacteria to develop resistance to antibiotics, though presumably it does take quite a while in bacteria terms. With regard to selection under extreme pressure from antibiotic poisons, bacteria have an advantage over more complex animals: they can evolve faster because they can exchange new genetic material directly rather than only passing it on to their children. This is isomorphic to cultural evolution in h humans: the way that a good idea can spread quickly through a human population.

The unintended consequences I see are three-fold. First, when the first antibiotics were used (i.e., penicillin) they were considered to be miracle drugs. People didn’t realize initially that miracles have a limited lifespan depending on how heavily you use them, and there are many penicillin resistant bacteria these days. Second, antibiotics were eventually spread through society in the form of soaps and creams. This turned out to be almost wholly counter-productive, in that it exposed bacteria to low levels of antibiotics, making it easier for them to evolve resistance before they were poisoned. Third, the industrial food system relies on antibiotics to keep animals alive and more-or-less well even though they live in exceedingly unhealthy conditions (packed in tightly, covered with feces, etc.). This has also greatly increased bacterial exposure to antibiotics, increasing resistance, thus unwittingly exchanging safer and cheaper food for increased danger in other areas of life.

The benefit of hospitals is that you can put experts and expensive equipment in one place where they can efficiently work to help people. The danger of hospitals is that you put all the sick people in the same place, which gives infections a steady supply of people who are weakened and less able to fight off infections. In effect hospitals become sanctuaries for infections. Two hundred years ago a hospital was not a place for healing; it was a place for dying. Modern medicine has changed that to an extraordinary degree. But antibiotic resistant bacteria remind us that is a hospital is a place you should go only when you have no other choice. Doctors making house calls is inefficient and expensive, but it would almost certainly be healthier for people who are not too sick to be cared for at home.

1 Comment »

  1. ncm said,

    March 2, 2010 @ 7:12 pm

    I think I read that the U.S. alone had something like 60,000 cases of superbug infections in hospitals in 2008. Apparently the overwhelming majority of cases were caused by hospital personnel not following sanitary procedures. I.e., at a very few hospitals that have experimented with strict use of checklists in intensive care wards, infection rates plummeted by more than an order of magnitude. It’s easy to believe that improved airflow design (particularly in waiting rooms — hold on, “waiting rooms”?!) could pick off another order of magnitude.

    Administrators of hospitals not using strict checklist procedures should be considered criminally negligent. That members of the medical profession are not spontaneously adopting these changes wholesale speaks volumes.

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