Comprehensive Surveillance of Ammonia Oxidizing Bacteria Able to Oxidize Ammonia in the Presence of Antibacterial Agents

• Project/Area Number: 18K18214
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 64020:Environmental load reduction and remediation-related
• Research Institution: Tokyo Denki University (2019-2020); Tokyo University of Technology (2018)
• Principal Investigator: TSUTSUI HIROFUMI 東京電機大学, 理工学部, 助教 (70620649)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2020: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000); Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
• Keywords: 抗菌薬 / アンモニア酸化細菌 / 排水処理 / 群集構造解析 / T-RFLP法 / 抗菌薬耐性機構 / 群衆構造解析

Outline of Final Research Achievements

Inhibition of biological nitrogen removal due to inflow of antibacterial agents is an important problem in livestock wastewater treatment. Comprehensive surveillance of ammonia oxidizing bacteria (AOB) able to oxidize ammonia in the presence of antibacterial agents was conducted by using improved microbial community analysis(T-RFLP). Inhibition of ammonia oxidization by the tetracycline was observed at 5 μg/ml or more. AOB strains assumed to be Nitrosomonas oligotropha/ureae might be important on ammonia oxidizing in the presence of tetracycline. Characteristics of Levofloxacin-resistant AOB strain isolated from activated sludge were investigated. Phylogenetic analysis based on the sequence of 16S rRNA gene and amoA gene showed this strain is closely related to Nitrosomonas europaea and Nitrosomonas eutropha. Furthermore, levofloxacin resistance of this strain would be due to the mutation of DNA gyrase.

Academic Significance and Societal Importance of the Research Achievements

畜産排水の窒素除去は流域の水質管理の面から重要な問題であり，家畜に抗菌薬を投与することで抗菌薬が流入した場合の影響を明らかにしつつ，安定な運転に寄与する細菌の情報と比較的簡易なモニタリング手法の開発は有効であると言える．本研究で，広く用いられているテトラサイクリンについて調査を行い，テトラサイクリン存在下で活性を示すAOBについて明らかにすることができ，効率的な畜産排水処理に寄与することが期待される．また，世界的に報告例のないAOBの薬剤耐性機構について，LVFX耐性株について明らかにすることができた．

Research Products

• [Presentation] Ammonia oxidizing kinetics of fluoroquinolone-resistant ammonia oxidizing bacterial consortium (2019)
  • Author(s): Hirofumi TSUTSUI and Taro URASE
  • Organizer: The 2019 International Conference on the "Challenges in Environmental Science and Engineering"（CESE-2019）
  • Int'l Joint Research
• [Presentation] アンモニア酸化細菌の群集構造解析を目的としたT-RFLP 法に適した制限酵素の検討 (2019)
  • Author(s): 筒井 裕文，浦瀬 太郎
  • Organizer: 第53回日本水環境学会年会