By Serena Gordon
TUESDAY, July 3 (HealthDay News) -- The number of infections occurring in community settings, such as gyms or schools, that are caused by the so-called "superbug" MRSA are declining, according to a study of more than 9 million active and non-active military personnel and their immediate families.
The superbug, known as methicillin-resistant Staphylococcus aureus or MRSA, is a type of staph bacteria that's resistant to many antibiotics, including penicillin and amoxicillin, according to the U.S. Centers for Disease Control and Prevention. About 2 percent of the U.S. population carry the MRSA bacteria in their nasal cavities, the CDC reports.
This latest study from the U.S. Department of Defense also found that the rate of serious infections known as bacteremia caused by MRSA had dropped between 2005 and 2010, in both community and hospital settings.
"These observations, taken together with the results from others showing decreases in the rates of health care-associated infections from MRSA, suggest that broad shifts in the epidemiology of S. aureus infections may be occurring," wrote study authors Dr. Michael Landrum, of the San Antonio Military Medical Center at Fort Sam Houston in Texas, and colleagues. What is not yet clear is the cause of the decline.
Results of the study are published in the July 4 issue of the Journal of the American Medical Association.
MRSA generally causes skin infections, but sometimes those infections can spread into the blood, causing a potentially life-threatening condition called bacteremia. MRSA is spread through direct contact or by touching surfaces or items that were touched by someone with MRSA. It's also spread through sharing personal items, such as razors or towels, according to the CDC.
Because recent research has suggested that MRSA, particularly in hospitals, is on the decline, the current study sought to get a better picture of the latest incidence of MRSA infections both in the community and hospital settings.
The researchers reviewed data from 9.2 million active and non-active military personnel and their immediate families. They searched for the first positive MRSA test, whether it was a skin infection or something more serious.
The percentage of skin and other soft-tissue infections caused by MRSA in the community setting peaked in 2006 at 62 percent, they found. By 2010, that was down to 52 percent. The rate of bacteremia caused by MRSA also went down in both the hospital and community settings.
People older than 65 and men were more likely to have bacteremia from MRSA in the community setting, according to the study.
"The proportion of skin and soft tissue infections attributed to MRSA has decreased, and the blood-borne infection rate caused by MRSA decreased, too," said Dr. Kenneth Bromberg, director of the Vaccine Research Center at The Brooklyn Hospital Center, in New York City. "It would be nice to be able to attribute this to better infection-control practices, but staph outbreaks come and go for reasons we don't always understand. The decrease in the rate of infections caused by MRSA may just be the way things go," he said.
Donna Armellino, vice president of infection prevention at North Shore University Hospital in Manhasset, N.Y., said this was an interesting study, and that the findings mirror a similar downturn in the percentage of infections caused by MRSA in her hospital system.
Armellino said she thinks people may be getting better at implementing infection-control practices. "I think there's a heightened awareness that wasn't there five to 10 years ago. Patients are more likely to ask health care workers if they've washed their hands, and some will ask how an instrument was cleaned or sanitized."
To prevent MRSA and other infections, she advised wiping down shared surfaces such as gym equipment or a shopping cart. And, she said, after you wipe the surface, let it dry before you touch it.
Bromberg also advised not to share towels or other personal items with anyone.