Study on dissemination pattens of amtimicrobial-resistant E. coli in sika deer in urban-forest landscape

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K20611
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0605:Veterinary medical science, animal science, and related fields
• Research Institution: National Institute for Environmental Studies (2023); Gifu University (2022)
• Principal Investigator: IKUSHIMA Shiori 国立研究開発法人国立環境研究所, 福島地域協働研究拠点, 研究員 (80967224)
• Project Period (FY): 2022-08-31 – 2024-03-31
• Keywords: 薬剤耐性菌 / キノロン耐性 / CTX-M産生 / 大腸菌 / 伝播 / シカ / 野生動物 / WGS解析

Outline of Final Research Achievements

We aimed to study prevalence and transmission patterns of CTX-M producing and quinolone-resistant E. coli in deer inhabiting Nara Park, neighboring mountain area of Nara Park, Mt. Odaigahara. The resistant isolates were further examined for WGS analysis. CTX-M producing and quinolone-resistant E. coli were prevalent in deer in Nara Park and neighboring mountain area of Nara Park. Some lineages were clonally transmitted among deer in Nara Park, whereas transmission between populations were not observed. CTX-M and quinolone-resistant E. coli derived from Nara Park deer include pandemic lineages, such as ST117, 38, and 58. Furthermore, epidemic lineages in Nara Park deer were categorized into extraintestinal pathogenic E. coli, uropathogenic E. coli, and avian pathogenic E. coli. These results showed potential risk of transmitting pathogenic AMR bacteria to human by contact between human and deer.

Free Research Field

野生動物医学

Academic Significance and Societal Importance of the Research Achievements

本研究では、山間部から都市部に近づくにつれてシカの薬剤耐性菌の保有率が高くなること、個体群内での伝播が生じることを明らかにした。この結果は、自然環境での薬剤耐性菌の拡散防止を検討する上で、野生動物においては人間社会とかかわりが大きいことが予想される個体群を中心にモニタリングやマネジメントを実施する必要性を示している。また、奈良公園のシカからは医療や獣医療で重要な抗菌薬に耐性の病原性大腸菌が複数系統分離されたことから、観光客等に対するシカとの適切な距離の保ち方や衛生管理の行い方についての普及啓発の重要性を示した。