Differential distribution and expression of Panton-Valentine leucocidin among community-acquired methicillin-resistant Staphylococcus aureus strains.
Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging threat worldwide. CA-MRSA strains differ from hospital-acquired MRSA strains in their antibiotic susceptibilities and genetic backgrounds. Using several genotyping methods, we clearly define CA-MRSA at the genetic level and demonstrate that the prototypic CA-MRSA strain, MW2, has spread as a homogeneous clonal strain family that is distinct from other CA-MRSA strains. The Panton-Valentine leucocidin (PVL)-encoding genes, lukF and lukS, are prevalent among CA-MRSA strains and have previously been associated with CA-MRSA infections. To better elucidate the role of PVL in the pathogenesis of CA-MRSA, we first analyzed the distribution and expression of PVL among different CA-MRSA strains. Our data demonstrate that PVL genes are differentially distributed among CA-MRSA strains and, when they are present, are always transcribed, albeit with strain-to-strain variability of transcript levels. To directly test whether PVL is critical for the pathogenesis of CA-MRSA, we evaluated the lysis of human polymorphonuclear leukocytes (PMNs) during phagocytic interaction with PVL-positive and PVL-negative CA-MRSA strains. Unexpectedly, there was no correlation between PVL expression and PMN lysis, suggesting that additional virulence factors underlie leukotoxicity and, thus, the pathogenesis of CA-MRSA.
Saïd-Salim
Battouli
B
TB Center, Public Health Research Institute, 225 Warren Street, Newark, NJ, 07103, USA.
Mathema
Barun
B
Braughton
Kevin
K
Davis
Stacy
S
Sinsimer
Daniel
D
Eisner
William
W
Likhoshvay
Yekaterina
Y
Deleo
Frank R
FR
Kreiswirth
Barry N
BN
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000633:toxicity; D001427:Bacterial Toxins; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology; D016521:Electrophoresis, Gel, Pulsed-Field; D005098:Exotoxins; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007956:Leukocidins / Q000235:genetics* / Q000378:metabolism* / Q000633:toxicity; D016106:Methicillin Resistance; D009504:Neutrophils / Q000502:physiology; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000472:pathogenicity*
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; C108483:leukocidin S-component protein, Staphylococcus; C074300:LukF protein, Staphylococcus aureus; D007770:L-Lactate Dehydrogenase