Elderly tend to get strain that's dominant in winter, while children more vulnerable to summer strain
FRIDAY, March 1, 2013 (HealthDay News) -- The threat posed to children and seniors by potentially deadly strains of antibiotic-resistant staph bacteria varies by season, new research finds.
Children have a greater risk for infection with methicillin-resistant Staphylococcus aureus (MRSA) in summer while seniors have a greater risk in winter, according to the study published online Feb. 28 in the American Journal of Epidemiology.
The reasons for these seasonal- and age-related risk patterns are unclear, according to study author Eili Klein, a researcher at the Johns Hopkins Center for Advanced Modeling in the Social, Behavioral and Health Sciences.
One reason may be the increased use of antibiotics in the winter. The winter strain of MRSA that is more likely to infect seniors is generally acquired in the hospital and resistant to more antibiotics. The summer strain of MRSA that is more likely to infect children is largely acquired outside of hospitals and is resistant to fewer antibiotics.
"Overprescribing antibiotics is not harmless," Klein said in a Hopkins news release. "Inappropriate use of these drugs to treat influenza and other respiratory infections is driving resistance throughout the community, increasing the probability that children will contract untreatable infections."
Klein noted that while MRSA strains show seasonal patterns, overall MRSA infections in the United States have not decreased over the last five years, despite efforts to control their spread. Hospitalizations for MRSA infections doubled between 1999 and 2005. Most of those cases were acquired outside of hospitals or other health care facilities.
For the study, Klein and colleagues analyzed national data from 2005 to 2009.
Further research on seasonal patterns of MRSA infections and drug resistance may help in the development of new treatment guidelines, prescription practices and infection control programs, Klein said.
The U.S. National Institute of Allergy and Infectious Diseases has more about MRSA (http://www.niaid.nih.gov/topics/antimicrobialresistance/examples/mrsa/pages/default.aspx ).
SOURCE: Johns Hopkins Medicine, news release, Feb. 28, 2013