ost adults who go to their doctors with a sore throat leave with a prescription for an antibiotic. In only one of approximately ten cases is this prescription appropriate. Researchers from Massachusetts General Hospital recently published a study in the Journal of the American Medical Association suggesting that antibiotics are vastly over-prescribed for sore throats caused by viral infections.
Below, infectious disease specialist Dr. Jason Kendler describes why these prescription behaviors have become so common in our medical culture, and the grave risks they pose.
What is an antibiotic?
JASON KENDLER, MD: Antibiotics are natural or synthetic substances that work to either kill bacteria or limit the growth of bacteria. They are therefore used to treat certain types of bacterial infections.
Antibiotics only treat bacterial infections?
That is correct. There are a limited number of medications that have some effectiveness in treating viral infections, but antibiotics, strictly speaking, are used to treat bacterial infections.
What is the difference between a viral infection and a bacterial infection?
Both viral infections and bacterial infections can be quite severe, and one of the main differences between them is that our treatment of viral infections is generally limited, whereas we have many more treatment options for bacterial infections.
How do bacteria and viruses behave differently?
The growth of bacteria does not require the presence of living cells.
Viruses are much smaller than bacteria, and require living cells in order to live and replicate. As a result, they are often difficult to isolate or grow in culture. Bacteria will grow readily in culture and are more easily identified.
If, in the vast majority of cases, antibiotics are not effective in the treatment of viruses, why are they so often prescribed to patients with viral illnesses?
I think the main reason is that patients nowadays have been educated about infections, and have seen how antibiotics work. They've had an infection, taken antibiotics, and gotten better, or they have friends who have had infections, received antibiotics and gotten better. They therefore assume that if they have an infection, they require antibiotics. The truth is that oftentimes this isn't the case-many of these infections are caused by viruses and would have gotten better anyway. But they know that antibiotics are out there, and they will demand them from their physicians.
From the perspective of the physician, it's actually a lot easier to give antibiotics to someone with a viral infection than not, because a lot of times that's what the patient expects. It takes a fair amount of time to explain to a patient the facts about a viral infection-what it is, the fact that antibiotics don't work for viral infections, and that they will most likely get better anyway. Many busy physicians do not have the time to explain these things to patients.
How does a bacteria become antibiotic-resistant?
Bacteria are under tremendous pressure to survive. If there are a whole bunch of bacteria growing in a certain location where antibiotics are present, the only bacteria that will survive are the ones that are resistant to that antibiotic. So the presence of antibiotics in fact encourages resistance, and the bacteria that are resistant then grow and proliferate.
Incomplete treatment can also cause antibiotic resistance as well. If a person does not finish a course of antibiotics, this can increase the chances of future resistance.
Are there certain prescription behaviors that speed bacterial resistance to antibiotics?
We know from various studies that the more antibiotics we use, the more drug resistance we will see.
What are the dangers of over-prescribing antibiotics?
There aren't very many new antibiotics being generated by pharmaceutical companies and by research laboratories, so in the near future we really have to rely on the antibiotics that we already have. If we misuse and overuse the antibiotics that we have, it's quite possible that we will run out of treatment options for types of bacterial infections that are treatable today.
Many physicians are using very high-powered antibiotics for infections that would respond to simpler antibiotics. We should be reserving the stronger antibiotics for certain infections. If they are used for other infections or if they are used in patients with viral infections, we're just going to add to the problem of resistance.
Bacterial resistance is not the only risk of excessive use of antibiotics. The antibiotics we use today are relatively safe, but certain adverse reactions can occur. These range from mild yeast infections and stomach upset to severe diarrhea and allergic reactions that can be deadly.
What exactly do we have to fear from antibiotic resistance?
We have to fear the possibility of infections with bacteria that we cannot treat with antibiotics. There are some bacteria that have become resistant to commonly used antibiotics, which can of course be problematic when we treat patients with infections caused by these bacteria. For example, we are seeing dramatic increases in resistance to penicillin and other antibiotics in the treatment of streptococcus pneumoniae (a type of strep), which is the most common cause of bacterial sinus infections, ear infections, and lung infections (pneumonia). This resistance is limiting our ability to treat these infections, and forcing physicians to use newer, more powerful antibiotics to treat them. In the future, we are likely to see resistance to the newer, more powerful agents as well.
Is this a very real concern in the infectious disease community?
Yes. This is a problem that has been identified and a problem that members of the infectious disease community are trying to combat through educational programs and consensus statements.
Who do you think is primarily responsible for slowing the pattern of prescribing unnecessary antibiotics?
Rectifying this problem will require that physicians become more educated about the proper use of antibiotics, and will require that patients not demand antibiotics when they're not indicated.
Do you feel that doctors really understand the ramifications of this kind of prescribing behavior?
No, I don't think we do, and I think that's our own fault for not educating ourselves and educating others.
But even if a patient demands antibiotics, a physician doesn't have to prescribe them, right?
Yes. But I think one trend we've seen in recent years-with access to the Internet and with medical advertising on a grand scale-is that patients think that they are educated, and sometimes feel very strongly about their demands for treatment. The combination of a partially-educated and demanding patient community, and physicians who have very limited time to talk with patients, often leads to unnecessary prescriptions.
Jason S. Kendler, MD, Weill Medical College of Cornell University, New York
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