Unfortunately, in more than 25 percent of cases studied, such prescriptions are useless because the infection stems from a virus, which cannot be treated with antibiotics. This overuse of antibiotics has a number of downsides, including that these types of drugs kill more of the “good” bacteria found in our bodies — which may lead to more side effects — and also contribute to the growth of antibiotic-resistant bacteria, according to Adam L. Hersh, M.D., Ph.D., an infectious disease expert, assistant professor of pediatrics at the University of Utah School of Medicine and senior author on a study published July 29, 2013, in the Journal of Antimicrobial Chemotherapy.
Discerning whether an infection is viral or bacterial can be tricky, according to Hersh, which probably accounts for much of the overuse of antibiotics. “It seems that the natural bias, when there is uncertainty about an infection’s cause, is to err on the side of prescribing antibiotics,” he says. “Our study found that the majority of prescriptions are for antibiotics that kill a wider range of bacteria, and that they are most likely to be given when they’re not needed, such as in cases of viral infections.”