Prevalence of antimicrobial-resistant Escherichia coli in fecal and environmental samples from areas inhabited by the endangered Gallirallus okinawae

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K06096
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 39060:Conservation of biological resources-related
• Research Institution: Nihon University
• Principal Investigator: SUMIYAMA Daisuke 日本大学, 生物資源科学部, 講師 (40565339)
• Co-Investigator(Kenkyū-buntansha): 安齋 寛 日本大学, 生物資源科学部, 教授 (70168029)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 薬剤耐性菌 / 環境汚染 / ヤンバルクイナ / 大腸菌 / 希少種保全

Outline of Final Research Achievements

We analyzed the prevalence of Escherichia coli and its antimicrobial resistance (AMR), as well as the distribution and genotype of E. coli in fecal of Gallirallus okinawae (Okinawa rail) and environmental soil and water samples from the its habitat area. The habitat of Okinawa rail was divided into a livestock farm area (LA) near human settlements and a forest area (FA) as a non-human living environment. In the result, the prevalence of antimicrobial-resistant E. coli in both of samples was more prevalent in the LA than FA. Furthermore, pulsed-field gel electrophoresis analysis revealed a similar genetic pattern of E. coli prevalence between fecal sample and soil sample of Okinawa rail in the LA. This suggests that there is the environmental pollution of AMR from livestock farm and the Okinawa rail may become a carrier of antimicrobial-resistant E. coli in the Yambaru region of Okinawa.

Free Research Field

保全生物学

Academic Significance and Societal Importance of the Research Achievements

本研究は、沖縄県北部ヤンバル地域にのみ生息する希少鳥類ヤンバルクイナの糞便および本種の生息環境試料（土や水）を対象に、人間生活からの環境汚染の影響が考えられる薬剤耐性大腸菌を指標として、畜産農家付近地域と森林地域とで保有率の比較を行った。本研究結果から、畜産農家付近の本種糞便および環境試料における薬剤耐性大腸菌保有率は森林地域より有意に高く、さらに多剤耐性検出も高いことが明らかになった。検出された大腸菌の遺伝子型解析結果から土試料と本種糞便との遺伝子型の一致も見られ、人間生活からの薬剤耐性菌漏洩が希少種への感染に及び、さらにそれらが運搬者となって森林へ拡散してしまうリスクを提唱した。