As part of the study, researchers also found that available drug classes used to treat urinary tract infections are losing their overall effectiveness. According to the CDC, they are the second-most common type of infection.
"These findings are especially disturbing because there are few new antibiotics to replace the ones that are becoming less effective," said Ramanan Laxminarayan, director of the Center for Disease Dynamic's Extending the Cure project, which addresses antibiotic resistance. "New drug development needs to target the types of drug-resistant bacteria that cause these infections."
The project has released details of the research on its website that tracks changes in antibiotic drug use and resistance.
Center for Disease Dynamics, http://www.cddep.org/map