PVL and CA-MRSA: The Plot Thickens

PVL did not increase the virulence of Staphylococcus aureus either in vitro or in murine models.

Panton-Valentine leukocidin (PVL) is widely thought to be a — if not the — major virulence determinant of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA). This hypothesis is based on a strong epidemiologic correlation between PVL and CA-MRSA disease and on PVL’s function as a leukocyte toxin. Now, researchers have tested this hypothesis using murine models and human neutrophil assays.

The investigators created PVL-negative (lukF/S-PV knockout) strains of well-characterized USA300 (Los Angeles County clone [LAC]) and USA400 (MW2) isolates. They then compared the virulence of these PVL-negative strains with that of their wild-type (PVL-positive) counterparts. They also tested seven other S. aureus strains of diverse …

Reviewing Author

Daniel J. Diekema, MD, MS