Researchers who thought they had identified the bacterial perpetrator of the often severe disease caused by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) had better keep looking: Scientists at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, have exonerated a toxin widely thought to be the guilty party.
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.
Message posted by: Rashmi Nemade