title: Relative contribution of Panton-Valentine leukocidin to PMN plasma membrane permeability and lysis caused by USA300 and USA400 culture supernatants.
abstract: Panton-Valentine leukocidin (PVL) is a cytolytic toxin associated with severe community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections. However, the relative contribution of PVL to host cell lysis during CA-MRSA infection remains unknown. Here we investigated the relative contribution of PVL to human polymorphonuclear leukocyte (PMN) plasma membrane permeability and lysis in vitro by using culture supernatants from wild-type and isogenic lukS/F-PV negative (Deltapvl) USA300 and USA400 strains. Using S. aureus culture conditions that favor selective high production of PVL (CCY medium), there was on average more PMN plasma membrane permeability and cell lysis caused by supernatants derived from wild-type strains compared with those from Deltapvl strains. Unexpectedly, plasma membrane permeability did not necessarily correlate with ultimate cell lysis. Moreover, the level of pore formation caused by culture supernatants varied dramatically (e.g., range was 0.32-99.09% for wild-type USA300 supernatants at 30 min) and was not attributable to differences in PMN susceptibility to PVL among human blood donors. We conclude that PMN pore formation assays utilizing S. aureus culture supernatants have limited ability to estimate the relative contribution of PVL to pathogenesis (or cytolysis in vitro or in vivo), especially when assayed using culture media that promote selective high production of PVL.
authors.affiliation: Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th Street, Hamilton, MT 59840, USA.
authors.forename: Shawna F
authors.initials: SF
authors.lastname: Graves
authors.forename: Scott D
authors.initials: SD
authors.lastname: Kobayashi
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Braughton
authors.forename: Binh An
authors.initials: BA
authors.lastname: Diep
authors.forename: Henry F
authors.initials: HF
authors.lastname: Chambers
authors.forename: Michael
authors.initials: M
authors.lastname: Otto
authors.forename: Frank R
authors.initials: FR
authors.lastname: Deleo
mesh_terms: D000704:Analysis of Variance; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001427:Bacterial Toxins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D003470:Culture Media; D005098:Exotoxins / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D006801:Humans; D007956:Leukocidins / Q000235:genetics / Q000378:metabolism*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000378:metabolism*; D009504:Neutrophils / Q000378:metabolism* / Q000382:microbiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D003470:Culture Media; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; D012333:RNA, Messenger; C108483:leukocidin S-component protein, Staphylococcus; C074300:LukF protein, Staphylococcus aureus