The doctor tried antibiotic after antibiotic, but the bacteria in the woman's body continued to proliferate. With only two drugs left, the doctor asked for my advice. An evolutionary biologist who studies antibiotic resistance, I suggested he use both drugs simultaneously. Since the two drugs had different modes of action, more mutations would be required for the bacteria to generate resistance to both drugs.
In truth, we had no idea what to do, and there wasn't enough justification to go with my theory. We know simultaneous drugs can stop resistance with HIV, but we have no idea about chronic bacterial infections. So the physician went with best practice--try one antibiotic until it fails, then switch to the other. The patient duly died, not from the heart failure that brought her into the hospital in the first place, but from the evolution of drug resistance among the bacteria in her body.
The Centers for Disease Control and Prevention claims that 23,000 Americans a year die from drug-resistant bacteria. There is a lot we can do. The bad news is, none of these actions will solve the problem alone.
Although we need science to provide solutions, the problems are fundamentally political. For example, it costs $1 billion to bring a new drug to market, and yet no market exists for antibiotics because their purchase price is so cheap and they are used for only short periods of time. Without government intervention, new antibiotics are unlikely to happen.
Decreasing the use of antibiotics on farms could substantially reduce resistance among some bacteria to drugs that are used both on farm animals and in humans, but it's not going to be a major solution because so many of the drugs we rely upon are used only in health-care settings.
Hygiene in hospitals is extremely important, but when a patient crashes and needs to be revived immediately, the nurse can't stand at the door and scrub down; he or she has to get in there. We can do hygiene better, but we can't do it perfectly.
An area where we can make a big difference is in antibiotic stewardship--prescribing the right drug, at the right dose, for the right duration, at the right time. The question is, "What is right?"
Consider duration of antibiotic use. We're all accustomed to 10-day or two-week courses, but where did these numbers come from? It turns out, almost all of them are completely arbitrary, and abiding by them may, in fact, be driving drug resistance.
Here's why. Antibiotic resistance can arise when susceptible bacteria are killed off by drugs, thereby releasing resistant bacteria from competition and enabling them to proliferate. In clinical trials, shorter durations of antibiotics (as little as three days) often are just as effective at improving health as longer durations, and some studies also show that drug resistance is reduced.
A British economist recently published an analysis suggesting that if we don't change our behaviors around antibiotic use, by the year 2050 more people will die of drug-resistant infections than of cancer, globally. That is scary. Science and policy need to work together to address this health problem.
This article first appeared in the Philadelphia Inquirer on August 5, 2016.
--Andrew F. Read
Andrew F. Read is the director of Penn State's Center for Infectious Disease Dynamics, Evan Pugh Professor of Biology and Entomology, and Eberly Professor of Biotechnology.