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'Superbugs' infiltrate hospitals, communities

By Anita Manning, USA TODAY

WASHINGTON — Drug-resistant bacteria are taking hold in hospitals and in the community, adding urgency to the need for new antibiotics and better infection-control measures, said scientists meeting here.

Among the most worrisome of these superbugs is MRSA, or methicillin resistant staphylococcus aureus, a germ once found primarily in hospitals. But it's popping up so often outside of health care settings that it is, "arguably, a true pandemic," said Steven Projan of Wyeth Research in Cambridge, Mass., who spoke at the Interscience Conference on Anti-microbial Agents and Chemotherapy, ending Monday.

Community-acquired MRSA usually causes boils and skin rashes but can lead to serious infections that require hospitalization. The strains found in hospitals, which generally infect the most seriously ill patients, cause blood infections, surgical site infections and pneumonia. Hospital- and community-acquired strains are different, researchers said, but both types are increasing. And in some areas they account for more than half of all staph infections.

"The prevalence of this is so high, it has fundamentally changed the way physicians treat (staph infections)," said David Hooper of Massachusetts General Hospital. "You have to treat for the possibility of MRSA" by prescribing a more potent antibiotic, usually vancomycin.

That in turn fuels the growing resistance to vancomycin of intestinal bacteria called enterococci, said Vincent Jarlier of Groupe Hôpital Pitié-Salpetrière in Paris. "Certainly the huge quantity of vancomycin used because of the MRSA epidemic is part of the (vancomycin-resistant enterococci) epidemic," he said. These resistant bacteria cause hard-to-treat intestinal infections.

MRSA infections are even showing up in animals, said veterinarian Scott Weese of Ontario Veterinary College at the University of Guelph, Canada. The bacteria may be passed from people to their pets, and vice versa, he said.

Among other drug-resistant bugs:

•Clostridium difficile, which causes diarrhea in hospital patients, is becoming more common, more toxic and more resistant to antibiotics, said Lance Peterson of Evanston (Ill.) Northwestern health care. Infections often can be treated, but there is a 16%-21% relapse rate, said Thomas Louie of the University of Calgary, Canada, and these may require repeated treatments, costing thousands of dollars to cure.

•Acinetobacter baumannii, which causes pneumonia and other infections and is found almost exclusively in hospitals, is developing resistance to several antibiotics and in some areas is resistant to all drugs, said Yehuda Carmeli of Tel Aviv Sourasky Medical Center in Israel. "The U.S. has been relatively spared," he said. But in his hospital, "in many cases we don't have any effective treatments."

Only a handful of new antibiotics are being developed to combat these resistant bugs. "There seems to be very little going into the pipeline," said Richard White, chief scientific officer of Vicuron Pharmaceuticals. Many large drug companies have dropped antibiotic research and are focusing on chronic diseases, developing drugs that must be taken repeatedly.

"There are more profitable areas to pursue," he said. "The problem with antibiotics is they work, and the patient is gone in a matter of days."