[PHILLY] Patients with a fever or congested lungs increasingly are being discouraged from taking antibiotics in the United States, and that’s a good thing. Those symptoms often are caused by viruses, in which case antibiotics ‐ which kill bacteria ‐ are the wrong approach.

But a new study finds that although antibiotics use has declined somewhat in the U.S., the nation remains the leading user of the drugs worldwide, with 3.3 billion doses administered in 2015. As many as one-third of these doses are thought to have been inappropriate, leading to the rise of "superbugs" ‐ bacteria that develop resistance to the medicines.

And in many countries, antibiotics use is increasing, the study authors reported Monday in Proceedings of the National Academy of Sciences.

From 2000 to 2015, antibiotics use per person jumped by 39 percent in a sample of 76 countries, the researchers found. The total number of doses consumed climbed even more, by 65 percent.

Some of that growth likely was beneficial, as it represented increased access to treatment in lower-income countries whose fortunes were improving, said lead author Eili Y. Klein, a fellow at the Center for Disease Dynamics, Economics and Policy, a nonprofit research institute in Washington.

But too often, antibiotics are deployed against infections that would be better addressed with preventive measures such as sanitation, said Klein, also an assistant professor of emergency medicine and epidemiology at Johns Hopkins University.