2019 Fiscal Year Final Research Report

Validation of microbial safety in drinking water in the world by comparative genomics of Vibrio cholerae

Research Project

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Project/Area Number	16H05830
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	海外学術
Research Field	Hygiene and public health
Research Institution	Hiroshima University (2019) Kyoto University (2016-2018)
Principal Investigator	MARUYAMA Fumito 広島大学, 学術・社会連携室, 教授 (30423122)
Co-Investigator(Kenkyū-buntansha)	竹村太地郎長崎大学, 熱帯医学研究所, 助教 (60572899) 中川一路京都大学, 医学研究科, 教授 (70294113) 野中里佐獨協医科大学, 医学部, 講師 (70363265) 植木尚子岡山大学, 資源植物科学研究所, 准教授 (50622023) 村瀬一典京都大学, 医学研究科, 研究員 (40710869)
Project Period (FY)	2016-04-01 – 2020-03-31
Keywords	コレラ / 比較ゲノム解析 / 薬剤耐性 / ゲノム疫学 / CRISPR
Outline of Final Research Achievements	We have collected Vibrio cholerae bacteria from the natural environment in Vietnam and Japan and have used an epidemiological approach for comparative genomic analysis. In Vietnam, we isolated O1 and 139 strains, but the frequency of the isolation was less than 5% and it was almost impossible to obtain O1 and 139 strains. The strains isolated did not possess cholera toxin gene. The genomic phylogenetic tree revealed that its genomic sequence is very different from that of the clinical isolates. We also found that the dominant clones in environmental (river) isolates in Japan differed from season to season. In addition, we also performed comparative genomic analysis of cholera from "ayu" (Japanese) in Japan in the 1970s, and found that only two clones were likely to be causative ones of Japanese fish, ayu, disease.
Free Research Field	環境遺伝生態学
Academic Significance and Societal Importance of the Research Achievements	本研究では、地理的に隔てられるが、食品の輸入等によるつながりをもつ 3 地域(チリ、ベトナム、日本)における水環境を研究対象として、コレラ菌のゲノム疫学的な解析を実施した。本菌は自然環境が生息地であることから、環境からコレラ菌を単離した。単離したコレラ菌は、臨床分離株とはそのゲノム特性が大きく異なっており、新しい病原性を生み出す遺伝子プールとなることから、環境分離株研究をさらに推進していく必要がある。