A novel comprehensive analysis method for Staphylococcus aureus pathogenicity islands

Authors

  • Yusuke Sato'o,

    1. Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Iwate
    2. The United Graduate School of Veterinary Sciences, Gifu University, Gifu
    Search for more papers by this author
  • Katsuhiko Omoe,

    1. Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Iwate
    2. The United Graduate School of Veterinary Sciences, Gifu University, Gifu
    Search for more papers by this author
  • Hisaya K. Ono,

    1. Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Iwate
    2. The United Graduate School of Veterinary Sciences, Gifu University, Gifu
    Search for more papers by this author
  • Akio Nakane,

    1. Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori
    Search for more papers by this author
  • Dong-Liang Hu

    Corresponding author
    • Department of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori, Japan
    Search for more papers by this author

Correspondence

Dong-Liang Hu, Department of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori 034-8628, Japan.

Tel: +81 176 249451; fax: +81 176 249451; email: hudl@vmas.kitasato-u.ac.jp

Abstract

Staphylococcus aureus pathogenicity islands (SaPIs) form a growing family of mobile genetic elements (MGEs) in Staphylococci. Horizontal genetic transfer by MGEs plays an important role in the evolution of S. aureus. Several SaPIs carry staphylococcal enterotoxin and SE-like toxin genes. To comprehensively investigate the diversity of SaPIs, a series of primers corresponding to sequences flanking six SaPI insertion sites in S. aureus genome were designed and a long and accurate (LA)-PCR analysis method established. LA-PCR products of 13–17 kbp were observed in strains with seb, selk or selq genes. Restriction fragment length polymorphism (RFLP) analysis showed that the products have different RFLP characteristics than do previously described SaPIs; they were therefore predicted to include new SaPIs. Nucleotide sequencing analysis revealed seven novel SaPIs: seb-harboring SaPIivm10, SaPishikawa11, SaPIivm60, SaPIno10 and SaPIhirosaki4, selk and selq-harboring SaPIj11 and non-superantigen-harboring SaPIhhms2. These SaPIs have mosaic structures containing components of known SaPIs and other unknown genes. Strains carrying different SaPIs were found to have significantly different production of superantigen toxins. The present results show that the LA-PCR approach can comprehensively identify SaPI diversity and is useful for investigating the evolution of S. aureus pathogenicity.

Ancillary