When the United Nations General Assembly meets in New York this week, on the agenda will be the overuse of antibiotics and the rapid spread of bacteria resistant to those lifesaving drugs.

The Centers for Disease Control and Prevention estimates that these “superbugs” cause 2 million illnesses and 23,000 deaths each year in the U.S. alone. Many of those infections, including MRSA and C. diff, originate in hospitals.

And a new study in JAMA Internal Medicine suggests that despite the growing concerns, many hospitals have failed to cut back on their overuse of the drugs, which could fuel the problem of drug-resistant bacteria.

In the most comprehensive study ever of antibiotic use in hospitals, CDC researchers looked at antibiotic prescribing patterns in almost 300 hospitals across the country, including 34 million hospital patients.

They concluded that between 2006 and 2012, 55 percent of hospital patients received at least one antibiotic while in the hospital or when being discharged. That was essentially the same as in previous years, though concerns about their overuse and the rise of drug-resistant bacteria had been rising steadily for years.

And while the researchers could not track antibiotic use in hospitals after 2012 because of changes in how the data were collected, they wrote that they do not believe prescribing patterns have changed much if at all since then.

That’s a worry, since recent studies show that roughly a third of antibiotics are prescribed when they aren’t needed, for things such as the flu and other viral infections that don’t respond to antibiotics. (Read more about when experts say antibiotics are and aren't needed.)

Read our special investigation "The Rise of Superbugs" and use our hospital ratings to compare hospitals in your area on infection rates and other measures.  

Another concern is that doctors reach too quickly for powerful, broad-spectrum drugs such as vancomycin and carbapenems when more-targeted drugs would be better choices.

In fact, the new study shows that use of those broad-spectrum drugs actually increased anywhere from three- to 18-fold, depending on the class, between 2006 and 2012.

Why do doctors continue to prescribe drugs that aren't needed and could potentially foster the spread of drug-resistant bacteria?

James Baggas, Ph.D., an epidemiologist at the CDC and the lead author of the new study, says that in some cases, providers might be unaware of treatment guidelines, or infections may be misdiagnosed, or doctors may rush too quickly to medications. "In some cases, additional information, especially bacterial cultures, will reveal that the patient does not have an infection, but often, the antibiotic therapy is not reassessed and is simply continued," he says.  

In an accompanying editorial, Ateev Mehrotra, M.D., and Jeffery Linder, M.D., both of Harvard Medical School, offer another explanation: “The overuse of antibiotics is not a knowledge problem or a diagnostic problem; it is largely a psychological problem,” they write. “We, as physicians, want to appear capable to our patients and not give the impression they have wasted either our time or their own."

To combat that, and the spread of drug-resistant bacteria, Consumer Reports has worked with professional medical groups like the American Academy of Family Physicians, as well as the CDC, on an effort to cut unnecessary prescribing by 20 percent over the next three years.