An update on community-associated MRSA virulence.

Staphylococcus aureus is a major health problem worldwide and the leading cause of bacterial infections in the United States. Historically, the success of S. aureus as a human pathogen has been facilitated by a strong propensity to develop antibiotic resistance and multidrug resistant strains are endemic in hospitals. However, one of the most striking developments in recent bacterial infectious disease history was the rapid emergence of community-associated methicillin-resistant S. aureus (CA-MRSA). First reported in the 1990s, CA-MRSA has since emerged worldwide and is epidemic in the United States. The pathogen is characterized by its ability to spread rapidly and cause infections in otherwise healthy individuals. This review focuses on current progress toward understanding the enhanced virulence properties of CA-MRSA, with an emphasis on Panton-Valentine leukocidin, alpha-hemolysin, and the recently discovered alpha-type phenol-soluble modulins.