Panton-Valentine leukocidin (PVL) is one of many toxins associated with S. aureus infection. Because it can be found in virtually all CA-MRSA strains that cause soft-tissue infections, several research groups previously have proposed that PVL is the key virulence factor.
But new evidence strongly suggests that is not the case. A study led by NIAID researchers at Rocky Mountain Laboratories (RML) in Hamilton, MT, shows that the two major epidemic CA-MRSA strains and the same strains with PVL removed are equally effective at destroying human white blood cells--our primary defense against bacterial infections--and spreading disease. The findings, which appear online in The Journal of Infectious Diseases, are surprising because many scientists had presumed that CA-MRSA uses PVL to target and kill specific white blood cells known as neutrophils.
"The Staphylococcus aureus bacterium is a growing global public health menace because of its rapid spread from hospital settings into communities of healthy people," says NIAID Director Anthony S. Fauci, M.D. "This is an evolving pathogen that in recent decades has developed resistance to common medical treatments and now is finding new mechanisms to spread and cause severe illness."
About 75 percent of CA-MRSA infections are localized to skin and soft tissue and usually can be treated effectively. CA-MRSA strains have enhanced virulence, meaning they can infect otherwise healthy people. One of the biggest problems with CA-MRSA skin infections is that they spread rapidly and have the potential to cause ill
Source:NIH/National Institute of Allergy and Infectious Diseases