Get access

Association of CiaRH with resistance of Streptococcus mutans to antimicrobial peptides in biofilms

Authors

  • Y. Mazda,

    1. Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
    2. Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
    Search for more papers by this author
  • M. Kawada-Matsuo,

    1. Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
    Search for more papers by this author
  • K. Kanbara,

    1. Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
    Search for more papers by this author
  • Y. Oogai,

    1. Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
    Search for more papers by this author
  • Y. Shibata,

    1. Section of Preventive and Public Health Dentistry, Division of Oral Health, Growth and Development, Kyushu University Faculty of Dental Science, Kyushu, Japan
    Search for more papers by this author
  • Y. Yamashita,

    1. Section of Preventive and Public Health Dentistry, Division of Oral Health, Growth and Development, Kyushu University Faculty of Dental Science, Kyushu, Japan
    Search for more papers by this author
  • S. Miyawaki,

    1. Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
    Search for more papers by this author
  • H. Komatsuzawa

    1. Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
    Search for more papers by this author

Hitoshi Komatsuzawa, Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Sakuragaoka 8-35-1, Kagoshima City, Kagoshima 890-8544, Japan Tel.: +81 99 275 6150; fax: +81 99 275 6158; E-mail: hkomatsu@dent.kagoshima-u.ac.jp

Summary

Streptococcus mutans is a cariogenic pathogen in humans. To persist in the oral cavity, S. mutans is resistant against several antibacterial factors derived from the host. In this study, we investigated the mechanism of resistance to cationic antimicrobial peptides (AMPs), which are innate immune factors in humans. Because dltA-D (teichoic acid biosynthesis) was reported to affect the susceptibility to AMPs in other bacterial species, we evaluated the susceptibility of a dltC knockout mutant of S. mutans to the AMPs human beta-defensin-1 (hBD1), hBD2, hBD3 and LL37. The dltC mutant exhibited significantly increased susceptibility to AMPs. Regulation of dltC expression involved CiaRH, a two-component system. Expression of dltC in the wild-type strain was significantly increased in biofilm cells compared with that in planktonic cells, whereas expression was not increased in a ciaRH knockout mutant. In biofilm cells, we found that susceptibility to LL37 was increased in the ciaRH mutant compared with that in the wild type. From these results, it is concluded that Dlt is involved in the susceptibility of S. mutans to AMPs and is regulated by CiaRH in biofilm cells.

Ancillary