Changing the way antibiotics are used

The results of the experiments outlined in the preceding section suggest that we humans had better think seriously about battling antibiotic resistance by trying to slow its progression rather than hoping we'll be able to deal with it after it occurs. To do that, we have to make real changes in how we use antibiotics — such as taking all our medicine. Taking only some of the antibiotics can create partially resistant bacteria, which may acquire subsequent mutations that make them even more resistant.

Here's just a little personal (and public) health note: Once you've knocked the infection down with the first half of the bottle, you've selected for the most resistant bacteria. The only way to kill those off is to finish the course of pills.

Another change is that people can use antibiotics less, which will decrease the selective pressure on the remaining sensitive bacteria. With fewer antibiotics around, sensitive bacteria would be less likely to be outcompeted by resistant bacteria. The idea is that, although humans can't stop using antibiotics to cure diseases, maybe we can stop hosing down the entire agricultural world with the same compounds we rely on to survive those diseases.

Antibiotics and agriculture

Of the millions of pounds of antibiotics used annually in the United States, less than half are used to treat human diseases. The majority of antibiotics are used in agriculture and not primarily for treating sick animals:

l Low doses of antibiotics are used as a food additive to increase animal growth rate. The mechanism by which low doses of antibiotics increase animal growth rate is unclear, but what is clear is that farms and feed-lots are growing reservoirs of antibiotic-resistance genes.

l Antibiotics are sprayed on fruit trees, resulting in a continuum of antibiotic concentrations starting from high at the center of the orchard and gradually fading to nothing at the edges of the antibiotic mist cloud. These continuous low doses of antibiotics in agricultural settings provide exactly the right situation for the evolution of fully resistant bacterial types.

Of the fraction of antibiotics in the United States that are used to treat human disease, evidence exists that many prescriptions are unnecessary. Patients want antibiotics even when they have no reason to think that their illness will respond to antibiotics — when they have the flu, for example — and the U.S. Centers for Disease Control and Prevention reports that more than 90 percent of physicians report feeling pressure to prescribe antibiotics that they know are unnecessary. So give your doctor a break!

For the past 60 years, antibiotics have allowed humans to live without fear of bacterial disease. With proper stewardship of this great resource, we can continue to enjoy the protections that antibiotics offer, but the point where we must take action to ensure the future efficacy of antibiotics is rapidly approaching. Scientists know with absolute certainty that bacteria will continue to evolve antibiotic resistance in response to human use of antibiotics. What is uncertain is whether we humans will make this evolution hard for them.

Was this article helpful?

0 0

Post a comment