Dec. 18 (UPI) -- Using antibiotics from time-to-time within a large population creates a higher risk of resistance to the drugs than heavy use among a small population, according to a new study.
The study, published Tuesday in eLife, is the first to take a population-wide look at the link between the distribution of antibiotic use and resistance to those antibiotics.
"We know that efforts to reduce inappropriate use of antibiotics are critical to addressing the problem of antibiotic resistance," Yonatan Grad, a professor of immunology and infectious diseases and senior author of the study, said in a press release. "We wondered whether every antibiotic prescription contributes equally to resistance, and whether, as some previous research has suggested, the most effective way to minimize antibiotic resistance would be to focus on the small fraction of people who use most of the antibiotics."
The researchers compared prescription data for 60 million people in the United States from 2011-2014 to numbers from 2012-2015 in the ResistanceOpen database, a site that tracks antibiotic resistance across the country.
The team then examined 72 pairs of antibiotics and bacteria across the United States and found that the more a specific antibiotic is used, the less effective it becomes. This can lead to the rise of certain bacteria, researchers said.
For example, states with more use of the antibiotic drug quinolones have more cases of e-coli.
As they dug deeper, the researchers found that low-intensity use of antibiotics spread out into a large group increased the likelihood resistance versus intense use within a smaller group.
"Our results show that most antibiotic use is occasional -- by people taking just one antibiotic course in a year -- and that this occasional use is more closely linked with antibiotic resistance than intense, repeated use," Grad said.
Overuse has made antibiotics less effective at fighting gonorrhea, tuberculosis, and foodborne illnesses, according to the World Health Organization.
The organization points to the over-prescription of antibiotics to people and animals as one reason for the problem.
"Our findings suggest that combating inappropriate antibiotic use among people who don't take many antibiotics may be just as important, or more important, to fighting resistance than focusing on high-intensity users," said lead author Scott Olesen, a postdoctoral fellow in the Department of Immunology and Infectious Diseases. "More antibiotic use generally means more antibiotic resistance, but it seems like the number of people taking antibiotics might matter more than the amount they're taking."