July 02, 2012
Washington, D.C. – Seasonal increases in antibiotic prescribing, particularly during flu season, are linked to short-term increases in antibiotic resistance, according to a study published online today in the journal Clinical Infectious Diseases.
Use of antibiotics exposes disease-causing microbes to powerful treatments and increases the selection pressure for resistant bacteria. The new research findings suggest that overuse of antibiotics, which often occurs during flu season, could make the growing problem of antibiotic resistance worse in the short-term.
The authors combined antibiotic prescribing data with information on resistance levels in hospitals and the community. They discovered that annual fluctuations in resistance to certain antibiotics were strongly correlated with antibiotic prescribing. The study was conducted by Extending the Cure, a project that examines policy responses to antibiotic resistance in the United States, and was funded in part by the Robert Wood Johnson Foundation.
In particular, the study authors found spikes in ampicillin- and ciprofloxacin-resistant E. coli in the month following increased aminopenicillin and fluoroquinolone prescriptions. Additionally, changes in ciprofloxacin- and clindamycin-resistant MRSA (methicillin-resistant Staphylococcus aureus) were correlated with seasonal increases in prescriptions of fluoroquinolones and macrolides, respectively.
In some cases, resistance levels were found to fluctuate by more than 3 percentage points in a pattern strikingly similar to prescription data, with a month lag. Using statistical techniques that allow the inference of causality, the researchers determined that the winter increase in antibiotic resistance was likely directly related to increases in antibiotic use.
The correlations are concerning, but they also suggest that interventions to reduce antibiotic overuse could help reduce seasonal spikes in resistance, said study author Ramanan Laxminarayan, noting previous research from Extending the Cure that up to one million antibiotic prescriptions each year are unnecessary. Patients and doctors should work together to reduce the number of unnecessary antibiotic prescriptions by not taking or prescribing antibiotics to treat viral illnesses, such as colds and flus. Flu shots also have an important role to play, reducing illness in winter months and leading to fewer doctor visits and fewer antibiotic prescriptions as a result.
Finally, the study found that increases in community antibiotic prescribing were causally linked with resistance in hospitals, which suggests that hospital antibiotic stewardship programs will need to be coupled with prescribing interventions in the community to be most effective.
The study is the first to use time-series analysis to examine seasonal relationships between antibiotic prescribing and resistance on a nationwide scale.
To see a visualization of the seasonal changes in resistance levels go to this page.
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About Extending the Cure
Extending the Cure is a research and consultative effort that examines policy solutions to address the growing problem of antibiotic resistance. The project is based at the Center for Disease Dynamics, Economics & Policy (CDDEP) in Washington, DC. To find out more, go to www.extendingthecure.org.
About the Robert Wood Johnson Foundation
The Robert Wood Johnson Foundation focuses on the pressing health and health care issues facing our country. As the nation s largest philanthropy devoted exclusively to health and health care, the Foundation works with a diverse group of organizations and individuals to identify solutions and achieve comprehensive, measurable, and timely change. For 40 years the Foundation has brought experience, commitment, and a rigorous, balanced approach to the problems that affect the health and health care of those it serves. 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. For more information, visit www.rwjf.org. Follow the Foundation on Twitter www.rwjf.org/twitter or Facebook www.rwjf.org/facebook.
