title: Global analysis of community-associated methicillin-resistant Staphylococcus aureus exoproteins reveals molecules produced in vitro and during infection.
abstract: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is a threat to human health worldwide. Although progress has been made, mechanisms of CA-MRSA pathogenesis are poorly understood and a comprehensive analysis of CA-MRSA exoproteins has not been conducted. To address that deficiency, we used proteomics to identify exoproteins made by MW2 (USA400) and LAC (USA300) during growth in vitro. Two hundred and fifty unique exoproteins were identified by 2-dimensional gel electrophoresis coupled with automated direct infusion-tandem mass spectrometry (ADI-MS/MS) analysis. Eleven known virulence-related exoproteins differed in abundance between the strains, including alpha-haemolysin (Hla), collagen adhesin (Cna), staphylokinase (Sak), coagulase (Coa), lipase (Lip), enterotoxin C3 (Sec3), enterotoxin Q (Seq), V8 protease (SspA) and cysteine protease (SspB). Mice infected with MW2 or LAC produced antibodies specific for known or putative virulence factors, such as autolysin (Atl), Cna, Ear, ferritin (Ftn), Lip, 1-phosphatidylinositol phosphodiesterase (Plc), Sak, Sec3 and SspB, indicating the exoproteins are made during infection in vivo. We used confocal microscopy to demonstrate aureolysin (Aur), Hla, SspA and SspB are produced following phagocytosis by human neutrophils, thereby linking exoprotein production in vitro with that during host-pathogen interaction. We conclude that the exoproteins identified herein likely account in part for the success of CA-MRSA as a human pathogen.
authors.affiliation: Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Burlak
authors.forename: Carl H
authors.initials: CH
authors.lastname: Hammer
authors.forename: Mary-Ann
authors.initials: MA
authors.lastname: Robinson
authors.forename: Adeline R
authors.initials: AR
authors.lastname: Whitney
authors.forename: Martin J
authors.initials: MJ
authors.lastname: McGavin
authors.forename: Barry N
authors.initials: BN
authors.lastname: Kreiswirth
authors.forename: Frank R
authors.initials: FR
authors.lastname: Deleo
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000032:analysis* / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D005098:Exotoxins / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D007525:Isoelectric Focusing; D008712:Methicillin / Q000494:pharmacology*; D016106:Methicillin Resistance; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009504:Neutrophils / Q000382:microbiology; D040901:Proteomics / Q000379:methods; D020539:Sequence Analysis, Protein; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000378:metabolism* / Q000472:pathogenicity; D053719:Tandem Mass Spectrometry; D014774:Virulence
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D005098:Exotoxins; D008712:Methicillin