Doctors in some hospitals prescribe up to three times as many antibiotics as doctors at other hospitals, putting patients at greater risk for deadly superbug infections, according to a federal study released Tuesday.

In addition, about one-third of the time, prescriptions to treat urinary tract infections and prescriptions for the drug vancomycin were given without proper testing or evaluation, or prescribed for too long, according to the Centers for Disease Control and Prevention.

During the past year, CDC officials have been raising the alarm about health threats from antibiotic resistance. Last fall, the CDC warned that the nation faces “potentially catastrophic consequences” if it doesn’t act quickly to combat the growing threat of antibiotic-resistant infections, which kill an estimated 23,000 Americans each year.

President Obama’s budget for the 2015 fiscal year proposes an additional $30 million for CDC initiatives to combat the growing crisis surrounding antibiotic resistance.

Tuesday’s report focuses on hospitals, where proper prescribing can have a direct and immediate impact on medical care and reduce infections, said CDC Director Thomas Frieden.

“We have to protect our antibiotics before our medicine chests run empty,” Frieden said in a teleconference with reporters. “Today, we’re getting specific about what hospitals can do.”

The CDC is strongly recommending that all hospitals, no matter how small, develop a seven-step antibiotic prescribing program that includes greater accountability and monitoring of antibiotic prescription and use, Frieden said. Key among those steps is an automatic reassessment within 48 hours of prescribing to make sure the drug choice is appropriate, he said.

John Combes, senior vice president at the American Hospital Association, said the organization has also been working on the issue and hopes to provide members with a tool kit later this year to help them set up antibiotic prescribing programs.

The study released Tuesday provides a more detailed look at antibiotic prescribing in hospitals and confirms the findings of previous studies that show antibiotic prescribing in hospitals is common and often incorrect.

The study looked at a variety of data on antibiotic use. One monitoring system used by all of the country’s acute-care hospitals found that from October 2012 to June 2013 – among 19 hospitals reporting antibiotic use for 266 patient-care locations – there was a threefold difference in usage rates in hospital medical-surgical wards.

Another data set showed that among 111 patients from 36 hospitals who were treated for urinary tract infections in 2011, 44 of them, or nearly 40 percent, did not have the proper testing or evaluation before antibiotics were prescribed. For 185 patients who received vancomycin, 66 patients, or more than 35 percent, did not have proper testing or evaluation.

The report also found decreasing the use of antibiotics that often lead to Clostridium difficile, or C. diff, by 30 percent could lead to 26 percent fewer of these deadly diarrheal infections. These drugs are known as broad-spectrum antibiotics that work against a wide range of bacteria.

In the United Kingdom, a concerted effort by hospitals against C. diff infections in recent years has led to more than a 50 percent reduction in the use of those broad-spectrum antibiotics and more than a 70 percent drop in the deadly infections, according to Arjun Srinivasan, the CDC’s associate director for healthcare associated infection prevention programs. Infectious disease experts called on hospitals to move quickly.

“Antibiotics are a precious resource, yet for decades we have not had a systematic approach in hospitals across the U.S. to ensure they are used wisely,” said Sara Cosgrove, a medicine and epidemiology professor at Johns Hopkins University and chair of the Society for Healthcare Epidemiology of America’s task force on antimicrobial stewardship.