Researchers have discovered that the most dangerous form of staph infection now occurring in the United States originates from a single strain of bacteria, not multiple strains as previously believed. These findings were published online today in the Proceedings of the National Academy of Sciences (PNAS).
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), an emerging public health concern, causes soft-tissue infections such as boils as well as life-threatening conditions that are difficult to treat. It is estimated that almost 100,000 cases of MRSA occurred in the
Our study confirms that a single strain, called USA300, of CA-MRSA is responsible for many of the devastating infections which have spread rapidly across the U.S. in recent years, said James Musser, MD, PhD, co-author of the PNAS paper and co-director of The Methodist Hospital Research Institute in Houston. Musser is also the director of the Center for Molecular and
The study, led by Frank R. DeLeo, PhD, at the National Institute of Allergy and Infectious Diseases Rocky Mountain Laboratories in
This discovery may lead to better tools to allow physicians to identify, diagnose, and treat this disease that has spread with extraordinary speed across the
To understand how CA-MRSA evolves in complexity and spreads geographically, researchers sequenced the genomes of 10 patient samples of the USA300 bacterium recovered from individuals treated for MRSA at different
Of the eight nearly indistinguishable USA300 patient samples, two caused far fewer deaths in laboratory mice than the others, highlighting an emerging view that tiny genetic changes among evolving strains can profoundly affect disease severity and the potential for drug resistance to develop.
Other study collaborators included Fred C. Tenover, PhD, of the Centers for Disease Control and Prevention in
Source: Methodist Hospital, Houston