Study details staph's broadening reach

Researchers hope to use these data to create interventions that will stop its spread.

By Victoria Stagg Elliott, AMNews staff. Jan. 30, 2006.

Nearly 90 million people, or about one-third of the country, carry Staphylococcus aureus in their noses. At least 2 million of them, or almost 1%, are colonized with the methicillin-resistant version, according to a study by Centers for Disease Control and Prevention researchers published in the Jan. 15 issue of the Journal of Infectious Diseases.

"MRSA is still relatively unusual," said Matthew J. Kuehnert, MD, lead author and a medical epidemiologist at the CDC's National Center for Infectious Diseases. "These data are giving us the baseline. Now we need to watch and see what's happening."

These numbers are the result of the analysis of samples collected from nearly 10,000 participants in the 2001-2002 National Health and Nutrition Examination Survey. And study authors say that although it is a cause for concern, because colonization tends to precede infection, it does not indicate a need to screen widely for MRSA in those who otherwise are healthy. Instead, they hope that this information eventually will lead to new strategies that might interrupt the bug's spread.

"I wouldn't recommend blindly swabbing individuals. There is a lot about staph colonization that we don't know," Dr. Kuehnert said. "We need to learn more in order to allow design of new, more effective interventions for the isolates that cause disease."

The study found significant differences in colonization by race and gender. But it is not known exactly what the true implications of these racial and gender differences are or what should be done for those who are MRSA carriers.