MRSA, or methicillin-resistant Staphylococcus aureus, is a type of antibiotic-resistant bacteria that is difficult to treat, and can be spread around hospitals and nursing homes by doctors, nurses and other staff.
But a new study brings some positive news: The number of "invasive" MRSA cases — severe infections that typically require hospitalization, and can be fatal — has declined significantly in the United States. In 2011, there were more than 30,000 fewer invasive cases than in 2005, the study shows. That's a 31 percent reduction in the rate of infection (per 100,000 people).
The drop was seen primarily in MRSA infections acquired at hospitals and nursing homes, where most cases are picked up, said Dr. Raymund Dantes, a physician and researcher at Emory University in Atlanta. These cases are called health-care-associated MRSA, and often involve pneumonia and infections of the bloodstream and surgical sites, according to the Centers for Disease Control and Prevention (CDC).
MRSA can also be spread outside hospitals in the community, in cases that typically involve skin infections. These MRSA infections can be spread by skin-to-skin contact in sports like wrestling, for example, and have been a problem in jails and homeless shelters or wherever people live in crowded, unsanitary conditions.
The number of community-associated MRSA cases has declined by 5 percent since 2005, according to the study, published today (Sept. 16) in the journal JAMA Internal Medicine. [ 5 Most Likely Real-Life Contagions ]
The decline of MRSA is likely due to hospital programs that encourage hand washing, and the wider use of sterile techniques to keep catheters and intravenous lines clean, Dantes said.
"The results are not surprising, since we have seen declines like this for several years, but it is encouraging that the trend is continuing," said Dr. Eli Perencevich, an epidemiologist at the University of Iowa who wasn't involved in the study. "Declines in the community-associated infections are not keeping up with hospital-acquired strains, suggesting we need more research in how to prevent community-associated infections."
The number of deaths associated with MRSA has also dropped. In 2005, more than 21,000 people in the U.S. were infected with MRSA at the time of their death, Dantes said. By 2011, the number had fallen to slightly more than 11,000 — a 47 percent drop.
In total, there were 80,461 invasive MRSA cases nationwide in 2011, compared with 111,261 MRSA cases in 2005, according to the study.
"One message that folks can take away: If you're in a hospital or health care setting, make sure to remind your doctors and nurses to wash their hands if you don't see them do it," said Dantes, who conducted the study while he was a researcher at the CDC.
"Doctors and other health care workers can prevent transmission of antibiotic-resistant bacteria in hospital settings by practicing good hand hygiene and following infection-control guidelines in their facilities," Perencevich added.