title: Epidemiological and genetic diversity of Staphylococcus aureus causing bloodstream infection in Shanghai, 2009-2011.
abstract: OBJECTIVE
  Staphylococcus aureus or methicillin-resistant Staphylococcus aureus (MRSA) has been an important pathogen causing bloodstream infections. Our study aimed to investigate the epidemiological and genetic diversity of clinical S. aureus isolates from patients with bloodstream infection in four hospitals of Shanghai from 2009 to 2011.
  
  
  METHODS
  A collection of S. aureus isolates causing bloodstream infection from four hospitals in the central part of Shanghai was carried out. Antimicrobial susceptibility testings of collected isolates were performed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines, and spa-type, multi-locus sequence typing, agr type and toxin gene profiling were performed to explore the molecular diversity. Moreover, MRSA strains were also characterized by Staphylococcal cassette chromosome mec (SCCmec) typing.
  
  
  RESULTS
  The drugs such as linezolid, teicoplanin and vancomycin were efficacious for treating S. aureus including MRSA bloodstream infection. Methicillin-sensitive Staphylococcus aureus (MSSA) strains displayed distinct diversity in molecular characterization and toxin genes, and three virulent MSSA strains encoding at least five toxins were detected. Five community-associated MRSA (CA-MRSA) strains were found, but the majority (88.7%) of MRSA strains belonged to two epidemic clones (ST239-MRSA- III and ST5-MRSA- II) with different toxin gene profiles among patients with bloodstream infection.
  
  
  CONCLUSIONS
  Healthcare-associated MRSA (HA-MRSA) strains were still the main pathogen causing bloodstream infections in spite of the emergence of CA-MRSA strains in hospital setting.
authors.affiliation: Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Chen
authors.forename: Wen-Kui
authors.initials: WK
authors.lastname: Wang
authors.forename: Li-Zhong
authors.initials: LZ
authors.lastname: Han
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Jin
authors.initials: J
authors.lastname: Tang
authors.forename: Qing-Zhong
authors.initials: QZ
authors.lastname: Liu
authors.forename: Yu-Chan
authors.initials: YC
authors.lastname: Huangfu
authors.forename: Yu-Xing
authors.initials: YX
authors.lastname: Ni
mesh_terms: D000483:Alleles; D016470:Bacteremia / Q000453:epidemiology*; D001427:Bacterial Toxins / Q000235:genetics; D002681:China / Q000453:epidemiology; D014644:Genetic Variation; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D013203:Staphylococcal Infections / Q000453:epidemiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects / Q000235:genetics*
chemical_list: D001427:Bacterial Toxins
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