| Project/Area Number |
17K18439
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Hygiene and public health
Bacteriology (including mycology)
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| Research Institution | Osaka Institute of Public Health |
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Principal Investigator |
Harada Tetsuya 地方独立行政法人 大阪健康安全基盤研究所, 微生物部, 主任研究員 (70516723)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2017: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Keywords | Outbreak関連大腸菌 / 食中毒 / 下痢原性 / 細胞付着性 |
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| Outline of Final Research Achievements |
To investigate the virulence factors in Escherichia coli O166:H15 isolates from diarrhea patients in several foodborne outbreaks, whole genome analyses, suckling mouse assays, bacterial adherence assays, and contact-dependent hemolytic activity tests were performed with 5, 2, and 2 isolates from 5 outbreak patients, 2 sporadic patients, and 2 asymptomatic carriers, respectively. Multilocus sequence typing revealed that the 8 isolates, except for one from an asymptomatic carrier, belonged to ST349 and a single locus variant of ST349. Core genome single nucleotide polymorphism-based analyses showed that the 8 isolates belonged to a single group. The four isolates from outbreak patients were positive for enteroaggregative E. coli heat-stable enterotoxin 1 gene and dispersin protein genes. In suckling mouse assays with a culture pellet of an outbreak isolate, fluid accumulation was observed. Additionally, several isolates from outbreak patients showed diffuse adherence to HeLa cells.
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| Academic Significance and Societal Importance of the Research Achievements |
複数の原因不明食中毒事例に共通して分離されるOutbreak関連大腸菌O166:H15について、供試株5株が異なるクローンでありながら単一系統群に属することが示された。本成果は、共通する病原因子の存在を示唆する可能性が高く、その公衆衛生学的意義は高い。また、2016年から2019年にも本菌が分離される集団食中毒事例が相次いで報告され、報道発表により社会的注目を集めた大規模事例もみられた。それゆえ、本菌への関心度は今後ますます高まることが予想されることから、本成果を基礎データとして病原性の解明が進むことが期待できる。
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