2023 Fiscal Year Final Research Report
Elucidation of the onset mechanism of streptococcal toxic shock syndrome on the bacterial side using an original mouse model
| Project/Area Number |
21K06979
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 49030:Experimental pathology-related
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| Research Institution | University of Occupational and Environmental Health, Japan |
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Principal Investigator |
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | 劇症型レンサ球菌感染症 / A群β溶血性レンサ球菌 / マウスモデル / csrS/csrR / 遺伝子突然変異 / 強毒化 |
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| Outline of Final Research Achievements |
To elucidate the mechanism by which group A beta-hemolytic Streptococcus (GAS) induces severe toxicity syndrome (STSS), a mouse model was used. Four strains of GAS were injected intramuscularly into mice, and some mice died after 20 days of infection. Genetic analysis of GAS isolated from blood, muscle, and organs of these mice showed that highly virulent strains with mutations in csrS or csrR appeared at the site of muscle injection and disseminated systemically. We hypothesized, but were unable to prove experimentally, that these mutations inhibit phosphorylation of the CovR protein, resulting in failure to suppress expression of virulence genes and thus increased virulence.
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| Free Research Field |
細菌学
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| Academic Significance and Societal Importance of the Research Achievements |
劇症型レンサ球菌感染症は近年急増しているが、その発症メカニズムは未だに不明な点が多い。本研究においては、A群β溶血性レンサ球菌が劇症型感染症を引き起こす際に、感染局所において強毒化した変異株が出現し全身に播種されることをマウスモデルで証明した。そのメカニズムとして遺伝子突然変異が考えられるが、本研究の結果からは、これまで考えられていたcsrSまたはcsrRの変異だけでは説明ができなかった。A群β溶血性レンサ球菌の強毒化に直接関与している遺伝子変異は、csrS/csrR 以外に存在する可能性があることを見出した。
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