Molecular basis of streptococcal toxic shock-like syndrome caused by group B streptococci

• Project/Area Number: 16K08795
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Bacteriology (including mycology)
• Research Institution: National Institute of Infectious Diseases
• Principal Investigator: Ikebe Tadayoshi 国立感染症研究所, 細菌第一部, 主任研究官 (20333362)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2017: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000); Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: レンサ球菌 / 劇症型溶血性レンサ球菌感染症 / 病原性 / B群レンサ球菌 / 細菌 / 遺伝子

Outline of Final Research Achievements

Mutations were identified in specific genes in streptococcal toxic shock-like syndrome (STSS) isolates. As a result of determining the nucleotide sequence of this gene in 50 strains of group B streptococcus of various serotypes that caused STSS, mutations were found in 13 of the 50 strains. On the other hand, in the vaginal strain, only 1 out of 50 strains had mutations. A mutant strain of this gene was constructed. In addition to genome-wide gene expression regulation analysis, in order to search for novel virulence genes, RNA was extracted from vaginal-derived strains and strains in which the causative gene of the vaginal-derived strain was mutated, and RNA-seq was performed. As a result, it was revealed that the expression of pathogenic factors such as hemolytic toxin, peptidase, and adhesion factor was increased.

Academic Significance and Societal Importance of the Research Achievements

B群レンサ球菌は、膣に常在していることや、小児に髄膜炎を引き起こすことが知られている。近年、B群レンサ球菌による劇症型感染症が報告されているが、その原因は分かっていなかった。本研究において、そのメカニズムが明らかとなり、将来的な治療や予防の観点から意義ある研究である。

Research Products

• [Journal Article] Streptococcal toxic shock syndrome caused by β-hemolytic streptococci: clinical features and cytokine and chemokine analyses of 15 cases. (2019)
  • Author(s): Yoshizawa S, Matsumura T, Ikebe T, Ichibayashi R, Fukui Y, Satoh T, Tsubota T, Honda M, Ishii Y, Tateda K, Ato M.
  • Journal Title: J Infect Chemother Volume: 25 Issue: 5 Pages: 355-361
  • DOI: 10.1016/j.jiac.2019.01.006
  • Peer Reviewed
• [Journal Article] Spontaneous mutations in Streptococcus pyogenes isolates from streptococcal toxic shock syndrome patients play roles in virulence. (2016)
  • Author(s): 1.Ikebe T, Matsumura T, Nihonmatsu H, Ohya H, Okuno R, Mitsui C, Kawahara R, Kameyama M, Sasaki M, Shimada N, Ato M, Ohnishi M.
  • Journal Title: Scientific Reports Volume: 6 Issue: 1 Pages: 28761-28761
  • DOI: 10.1038/srep28761
  • Peer Reviewed / Open Access
• [Presentation] 劇症型溶血性レンサ球菌感染症の疫学（分子疫学を含む） (2019)
  • Author(s): 池辺忠義
  • Organizer: 第93回日本感染症学会学術講演会
• [Presentation] 連鎖球菌感染症の疫学 (2018)
  • Author(s): 池辺忠義
  • Organizer: 第39回日本食品微生物学会学術総会
  • Invited
• [Presentation] IL-6-deficient immature myeloid cells have no protective function against Streptococcus infection (2017)
  • Author(s): 松村隆之、池辺忠義、大西真、阿戸学
  • Organizer: 第90回日本細菌学会総会
  • Place of Presentation: 仙台国際センター
  • Year and Date: 2017-03-19