Analysis of natural reservoir of Escherichia albertii, an emerging zoonotic pathogen

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K06396
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 42020:Veterinary medical science-related
• Research Institution: Osaka Metropolitan University (2022-2023); Osaka Prefecture University (2020-2021)
• Principal Investigator: Hinenoya Atsushi 大阪公立大学, 大学院獣医学研究科, 准教授 (20548490)
• Co-Investigator(Kenkyū-buntansha): 山崎 伸二 大阪公立大学, 生命環境科学研究科, 教授 (70221653)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: Escherichia albertii / アライグマ / 自然宿主 / Eacdt / stx2

Outline of Final Research Achievements

Escherichia albertii is an emerging zoonotic enteropathogen, which has caused several foodborne outbreaks particularly in Japan. This study performed the survey of wild raccoons for this bacterium in Osaka, Japan as well as the US, and revealed the followings: 1) E. albertii was frequently detected in the individuals from Osaka (~60%) and the US (~25%). 2) There was the seasonal change of the prevalence of E. albertii in raccoon individuals in Japan. 3) The raccoons were frequently co-infected with different E. albertii clones. 4) Raccoons carried E. albertii with diverse bacteriological characteristics, and the isolates were considered pathogenic to humans. Together, this study revealed that raccoons are one of the natural reservoirs of this bacterium and could be the source of direct or indirect human infections. The findings enable us to do further research to clarify the transmission dynamics of E. albertii and the routes of human infections.

Free Research Field

獣医細菌学

Academic Significance and Societal Importance of the Research Achievements

E. albertiiの臨床情報には徐々に蓄積されつつあるものの、感染源や感染経路については不明な点が多い。本研究では、E. albertiiの自然宿主の1つが野生アライグマであること、アライグマが保菌するE. albertiiはヒトへの病原性をもつと考えられること、原産国に生息する個体も保菌することを見出した。アライグマは、侵略的外来種として日本やヨーロッパを中心に個体数および生息域を増加させており、ワンヘルスの観点からも注意が必要な動物種であると考えられる。得られた知見により、E. albertiiの環境内動態およびヒトへの感染経路の解明に向けた更なる解析が可能になると期待できる。