The community-associated strain of the deadly superbug MRSA—an infection-causing bacteria resistant to most common antibiotics—poses a far greater health threat than previously known and is making its way into hospitals, according to a study in the December issue of Emerging Infectious Diseases. The new threat is easily picked up in fitness centers, schools, and other public places and has increased the overall burden of MRSA within hospitals, the report found.
The study, which analyzed data from more than 300 microbiology labs serving hospitals all over the United States, found a seven-fold increase in newer “community-associated” strains of methicillin-resistant staphylococcus aureus, or MRSA, in outpatient hospital units between 1999 and 2006. According to study authors, this increase threatens hospital safety because many hospitals share their resources, such as surgical sites, or have doctors or patients that move back and forth between the different areas of the hospital.
“This emerging epidemic of community-associated MRSA strains simply adds to the already high MRSA burden in hospitals,” said Ramanan Laxminarayan, Principle Investigator for Extending the Cure, a project examining antibiotic resistance at the Washington, D.C.-based think tank Resources for the Future. Extending the Cure is supported by the Robert Wood Johnson Foundation’s Pioneer Portfolio, which funds innovative ideas that may lead to breakthroughs in the future of health and health care.
Over the length of the study period, researchers found that MRSA increased more than 90 percent among outpatients and now accounts for more than 50 percent of all Staphylococcus aureus infections. The findings suggest that this was due almost entirely to an increase in community-associated strains, which jumped from 3.6 percent of all MRSA infections to 28.2 percent—a seven-fold jump from 1999 to 2006. Similar increases in inpatients suggest that these strains are spreading rapidly into hospitals as well.
MRSA kills an estimated 20,000 people in the United States each year. The superbug, which is resistant to most common antibiotics, can attack wounds and trigger potentially lethal blood stream infections. Community-associated strains, while generally less virulent and susceptible to more antibiotics, can still cause significant morbidity and mortality.
“MRSA has generally been a significant problem only in hospitals,” said Eili Klein, the report’s lead author and Resources for the Future researcher. “But the findings from this study suggest that there is a significant reservoir in the community as well.” This community reservoir leads to a dangerous spread of community-associated strains from outpatient units into hospitals, according to Klein.
To curtail this spread, hospitals will need to step up infection control procedures, including those practiced in outpatient units. This study and others suggest that the most effective way of containing MRSA and other superbugs is by employing surveillance and infection control on a regional basis.
“The movement of community-associated strains into the hospital also points to the urgent need for rapid tests that can identify the strain of MRSA,” Klein said. Some MRSA strains, particularly those coming into the outpatient departments, are vulnerable to a wider range of cheap antibiotics. With a rapid test, a hospital doctor could prescribe a cheaper, but still effective drug to combat an infection—a strategy that might reduce health care costs and help preserve the nation’s supply of antibiotics, according to authors.
About Resources for the Future
Extending the Cure is a project at Resources for the Future, a Washington, D.C. think-tank with more than a half a century of experience applying economics to some of our nation’s most pressing problems. Extending the Cure: Policy Responses to the Growing Threat of Antibiotic Resistance is a report produced by the project.
About Robert Wood Johnson Foundation
As the nation's largest philanthropy devoted exclusively to improving the health and health care of all Americans, the Robert Wood Johnson Foundation works with a diverse group of organizations and individuals to identify solutions and achieve comprehensive, meaningful and timely change. The Foundation's Pioneer Portfolio supports innovative ideas and projects that may lead to important breakthroughs in health and health care. When it comes to helping Americans lead healthier lives and get the care they need, the Foundation expects to make a difference in your lifetime.