Methicillin-resistant Staphylococcus aureus infections doubled at academic medical centers in the U.S. between 2003 and 2008, according to a report published in Infection Control and Hospital Epidemiology.
Researchers from the University of Chicago Medicine and the University Health System Consortium estimated hospitalizations increased from about 21 of every 1,000 patients hospitalized in 2003 to about 42 of every 1,000 in 2008.
“The rapid increase means that the number of people hospitalized with recorded [methicillin-resistant Staphylococcus aureus] MRSA infections exceeded the number hospitalized with AIDS and influenza combined in each of the last 3 years of the survey,” study author Michael Z. David, MD, PhD, stated in a University of Chicago Press Journals release.
The authors performed a retrospective cohort study involving hospitalized patients at 90% of nonprofit U.S. academic medical centers from 2003 to 2008, looking at MRSA infection data from a hospital discharge database. The team adjusted the data for underreporting of MRSA, using patient observations from the University of Chicago Medical Center and three other hospitals to determine the rate of error and use it as a proxy to correct data found in the database.
“The mean sensitivity of administrative data for MRSA infections at the University of Chicago Medical Center in three 12-month periods during 2004 to 2007 was 59.1%,” the authors wrote.
Using this as their basis for estimate adjustment, the researchers found the number of MRSA infections per 1,000 U.S. academic medical centers increased from 20.9 in 2003 to 41.7 in 2008.
According to the release, the findings run counter to a recent study from the Centers for Disease Control and Prevention (CDC) that found MRSA cases in hospitals were declining. The CDC study excluded infections of the skin, which this study included.
“I think this is still an underestimate of actual cases,” David stated. “But we can say with some assurance that this correction gives us a more accurate lower bound for how many cases [of MRSA] there actually are. What’s clear from our data is that cases were on the rise in academic hospitals from 2003 to 2008.”
David MZ, Medvedev S, Hohmann SF, et al. Increasing burden of methicillin-resistant Staphylococcus aureus hospitalizations at U.S. academic medical centers, 2003. Infect Control Hosp Epidemiol. 2012. doi: 10.1086/666640