USA300 abroad: global spread of a virulent strain of community-associated methicillin-resistant Staphylococcus aureus.

The epidemic of USA300-0114 methicillin-resistant Staphylococcus aureus (MRSA) in the USA has been remarkable for its virulence and for its ability to cause infections in both the community and healthcare settings. Although it has mainly been associated with skin and soft tissue infections, particularly furunculosis, it has also caused severe life-threatening conditions such as necrotizing pneumonia, osteomyelitis, and septic arthritis. This strain or a closely related Latin American variant has now spread to multiple countries on five continents, where associated clinical and epidemiological features have been in keeping with those seen in the USA. Furthermore, it has become the dominant community-associated MRSA strain in five countries. It is now a major international epidemic strain, but whether it will supplant established community-associated strains in other countries remains to be seen.