新型PPCPs环境污染物质粒介导喹诺酮耐药基因的环境传播生态风险研究

Since their introduction for human therapy 60 years ago, antibiotics have shown to be a remarkable success and constitute one of the most relevant medical inventions for reducing human morbidity and mortality. Unfortunately, overuse in human medicine and agricultural uses, particularly in livestock, contribute significantly toward the problem of antibiotic resistance, which has become a recognized medical problem. In the recent year, the explosive spread of antibiotic resistance determinants among pathogenic, commensal, and environmental bacteria had reached a global dimension. The antibiotic resistant bacteria together with antibiotics are discharged into the environment through pathways such as domestic sewage and hospital wastewater and are selected and promoted in the environment, where several antibiotics exist at low levels. Bacteria in the environment can acquire resistance genes from other bacteria in their vicinity in a process known as "horizontal transfer" at chronic low-level exposure to antibiotics and therefore contribute significantly to increased gene frequencies and dissemination of resistance genes into other ecosystems. The pollution of natural ecosystems by antibiotics and resistance genes might have consequences for the evolution of the microbiosphere. Therefore, antibiotic resistance genes (ARGs) in the environment have been studied as an emerging contaminant since resent years. .This study was conducted to investigate the occurrence and quantity of plasmid-mediated quinolone resistance (PMQR) genes from swine feedlots and their surrounding environment. To investigate the levels of quinolone residues in the samples, ultra performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-MS/MS) methods will be used to determine the concentrations of ten typical quinolones. Furthermore, the phylogenetic analysis will be performed to investigate the diversity of PMQR genes genotypes. Finally, conjugation, transformation and southern hybridization techniques will be used to evaluate the transferability of the plasmid-mediated quinolone resistance determinants in the PMQR-positive isolates collected from the environment samples. The results of this program will provide fundamental data for proper risk assessment and environmental management of ARGs, the emerging contaminants in environment.

作为一类新的环境污染物，抗生素耐药基因的环境污染已成为一个新的全球性污染问题，严重危险人类公共健康。其造成的严重生态健康效应是目前环境化学领域最新研究热点之一。但是抗生素耐药基因污染这一当前国际环境领域中的研究热点在我国却还没有引起足够重视。本项目对北京市代表性养殖场周围土壤及水环境样本开展质粒介导的喹诺酮类抗生素耐药（plasmid mediated quinolone resistance，PMQR）基因的污染分布情况调查，同时对喹诺酮类抗生素的环境浓度与耐药基因的污染水平进行相关性分析，探讨抗生素浓度对耐药基因富集和扩散的影响；进而解析环境中PMQR基因的质粒指纹图谱以及独特遗传背景，探讨PMQR基因的水平转移风险，以期为我国建立抗生素耐药性的环境生态风险性评估和控制体系提供基础数据及理论支持。

自四十年代被广泛使用以来，抗生素对控制人类及动物感染性疾病发挥了巨大的作用。然而近年来，由于在人医临床以及农业，尤其是畜牧业中的滥用，如今细菌耐药性迅速蔓延。作为一类新的环境污染物，抗生素耐药基因的环境污染已成为一个新的全球性污染问题，严重危险人类公共健康。其造成的严重生态健康效应是目前环境化学领域最新研究热点之一。但是抗生素耐药基因污染这一当前国际环境领域中的研究热点在我国却还没有引起足够重视。本项目对北京市代表性养猪场废水和周围农田土壤样本以及大型生活固体垃圾填埋场周围土壤样本，开展了质粒介导的喹诺酮类抗生素耐药（plasmid mediated quinolone resistance，PMQR）基因的污染分布情况调查，提示养猪场和垃圾填埋场环境均是环境中耐药基因污染的储存库；同时采用超高效液相色谱与质谱串联（UPLC-MS/MS）的方法对环境样本中喹诺酮类抗生素的浓度进行了测定，并将其与耐药基因的污染水平进行相关性分析，结果显示喹诺酮类抗生素环境污染浓度对PMQR基因的富集和扩散具有正相关作用；进而对231株环境源大肠杆菌的耐药表型和突变频率进行了测定，发现大肠杆菌突变频率与多重耐药情况间存在正向联系。这些研究结果可为我国建立抗生素耐药性的环境生态风险性评估和控制体系提供一定的基础数据及理论支持。