Staphylococcus aureus leukocidin: a new virulence factor in cutaneous infections? An epidemiological and experimental study.

Panton-Valentine leukocidin (PVL) is a Staphylococcus aureus (SA) exotoxin, which kills human granulocytes and monocytes in vitro. Among 43 SA strains from cutaneous infections, 12 were PVL producers, whereas among 49 blood culture strains, only 1 produced PVL. Most PVL-producing strains (11/22) came from 22 primitive cutaneous infections, especially furuncles and abscesses, while only 1 PVL-producing strain came from 21 secondary infections of dermatoses such as bullous or pruritic diseases. Intradermal injections of PVL in rabbits induced edema, erythema and necrosis; histopathological changes at the injection sites consisted mainly in leukocytoclasis and vascular necrosis. All changes were dose dependent, and previous immunization of rabbits partially neutralized PVL-induced effects. Production of PVL in vivo after injections of bacteria seems to be low, and the histopathological lesions induced in the rabbit skin do not appear to be specifically related to PVL activity. However, PVL is a good candidate as a new virulence factor in cutaneous SA infections.