抗生素降解菌土壤输入驱动的耐药组变异及机制研究

抗生素的滥用及细菌耐药的加剧已成为全球面临的严重问题。抗生素降解菌是环境中去除抗生素的重要元件，但其应用亦可能向环境额外输入大量抗生素抗性基因（ARGs）。基于抗生素降解菌的双刃效应，为正确认识其应用对环境耐药发展的影响：1）以土壤为对象，选择四环素降解菌OTC-16和DT1，构建以土壤类型、抗生素污染水平等为自变量的降解菌输入模型；2）结合耐药谱分析和ARGs高通量检测，明确降解菌土壤输入驱动的耐药组结构和功能变异特征及其影响因素；3）研究外源降解菌定植和土壤内源细菌群落的适应性调节，明确不同耐药变异模式的土壤细菌群落重构特征；4）采用“荧光原位杂交-流式细胞分选-高通量测序”等方法研究降解菌来源耐药质粒的水平转移。由上，阐明抗生素降解菌土壤输入驱动的耐药组变异规律及产生风险性的机制，为抗生素降解菌应用的安全性预测和控制提供参考，丰富环境污染下的耐药性进化发展理论。

The antibiotic abuse and increased antimicrobial resistance have become the world facing serious problems. Antibiotic-degrading bacteria (ADB) are important materials for the removal of antibiotics in the environment, but their application may also lead to the environmental release of antibiotic resistance genes (ARGs). The double-edged effect of ADB suggests that the impact of ADB on soil resistome might be different from that of the previously reported ARGs carriers. This project pays attention to the impact of ADB on the soil resistance with the aim of evaluating the potential risks of environmental application of ADB. The research contents can be divided into four parts: (1) Tetracycline-degrading bacteria such as Arthrobacter nicotianae OTC-16 and Stenotrophomonas maltophilia DT1 will be used for constructing a soil experimental model. The soil type, the soil residual antibiotic concentration and the bacteria type are variable in the experimental model. (2) The effects of ADB on the function and structure of soil resistome will subsequently be characterized by using the above-mentioned experimental models. The antimicrobial resistance spectrum analysis of soil microbiota and the high-throughput determination of ARGs will be performed for soil samples. (3) The re-structure of antibiotic resistant bacteria (ARB) in soils will be studied by the investigation on the colonization of exogenous ADB and the adaptive regulation of soil inherent bacterial community. (4) The horizontal transfer of resistant plasmids from ADB will be studied by combined using FISH, flow cytometry and high-throughput sequencing. The mechanism on how ADB influence the function and structure of soil resistome will be clarified. This project would provide a reference for evaluating the future development trend of ADB and enriches the evolutionary theory of antimicrobial resistance under environmental dimension.