Estimation of sources of antibiotic resistant bacteria and analysis of their aquired resistance in Southeast Asian water environment

2014 Fiscal Year Final Research Report

• Project/Area Number: 24404017
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 海外学術
• Research Field: Civil and environmental engineering
• Research Institution: Yamagata University
• Principal Investigator: WATANABE Toru 山形大学, 農学部, 准教授 (10302192)
• Co-Investigator(Kenkyū-buntansha): HONDA Ryo 金沢大学, 理工研究域, 助教 (40422456)
• Co-Investigator(Renkei-kenkyūsha): MASAGO Yoshifumi 東北大学, 未来科学技術共同研究センター, 准教授 (50507895)
• Research Collaborator: WILAI Chiemchaisri カセサート大学(タイ王国), 工学部, 准教授 ; CHART Chiemchaisri カセサート大学(タイ王国), 工学部, 准教授
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 薬剤耐性菌 / 大腸菌 / 水環境 / 耐性遺伝子 / 下水処理 / 病院排水 / 国際研究者交流 / タイ王国

Outline of Final Research Achievements

1) Twenty-four kinds of resistance genes were detected from isolates of Escherichia coli (n=316) from the Chao Phraya River in Thailand. Detection rates of resistance genes to penicillins and tetracyclines were relatively high. Phylogenetic analysis revealed that these isolates were categorized into five clusters. We could not find significant differences in detection rates of any antibiotic resistance genes among the clusters, indicating the difficulty to estimate origins of the resistance genes carried by E. coli based on their phylogenetic relationship.
2) We conducted an experiment to treat synthetic municipal wastewater using bench-scale reactor of activated sludge process in Thailand. It demonstrated the increase in resistant rate to norfloxacin (NOR) of E. coli in the reactor when NOR was added at a high concentration as reported in hospital wastewater. We also found that the NOR resistance of E. coli appeared to be induced by a low concentration of NOR (<50 ng/L) in river water.

Free Research Field

水環境工学