Differential distribution and expression of Panton-Valentine leucocidin among community-acquired methicillin-resistant Staphylococcus aureus strains.
J Clin Microbiol
; 43(7): 3373-9, 2005 Jul.
Article
en En
| MEDLINE
| ID: mdl-16000462
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.
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Bases de datos:
MEDLINE
Asunto principal:
Staphylococcus aureus
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Resistencia a la Meticilina
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Infecciones Comunitarias Adquiridas
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Leucocidinas
Límite:
Humans
Idioma:
En
Revista:
J Clin Microbiol
Año:
2005
Tipo del documento:
Article
País de afiliación:
Estados Unidos