Analysis of inter-phage interaction and its impacts on the evolution of enterohemorrhagic E. coli

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K07116
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 49050:Bacteriology-related
• Research Institution: Kyushu University
• Principal Investigator: Nakamura Keiji 九州大学, 医学研究院, 助教 (60706216)
• Co-Investigator(Kenkyū-buntansha): 澤口 朗 宮崎大学, 医学部, 教授 (30336292)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 腸管出血性大腸菌 / 志賀毒素ファージ / サテライトファージ / ヘルパーファージ

Outline of Final Research Achievements

Bacteriophages (or phages) play major roles in the evolution of bacterial pathogens. Multiple phages are often integrated in a host chromosome as prophages, providing various possibilities for prophage-prophage interactions in bacterial cells. The present study investigated an inter-phage interaction between "phage in phage" newly identified in the enterohemorrhagic E. coli (EHEC) O145 strains, and revealed (i) that this coexistence of phages could affect phenotypes of the phages, ii) that phages integrating another prophage may be occurred in strains belonging to various serotypes of EHEC and enteropathogenic E. coli (EPEC), and iii) that this system possibly promote evolution as pathogenic bacteria and genetic diversity in host E. coli. These findings obtained here provide novel insights for not only the research communities working on EHEC/EPEC and their phages but also a wide range of researchers in basic and medical microbiology as well as bacterial evolution.

Free Research Field

細菌学

Academic Significance and Societal Importance of the Research Achievements

様々な菌種において、個々のファージのゲノム構造や宿主菌の進化や多様化における役割が明らかとなっている。しかし、細菌の細胞内に複数存在するファージ間の相互作用とそれが宿主菌の進化や多様化に与えるインパクトは従来の研究ではほぼ未解明の領域であった。この点において、本研究成果が今後のファージ研究に与える影響は小さくない。また、腸管出血性大腸菌は感染患者に重篤な症状を引き起こしうる、公衆衛生上重要な病原細菌である。今回の解析により、本病原細菌の病原性に対する理解においても新しい情報を提供したことで、今後の高病原性大腸菌のサーベイランスなどに貢献できると考えられる。