典型抗生素抗性基因在畜禽养殖场大气气溶胶中的污染特征研究

Antibiotic resistance genes as emerging contaminants, posing a threat to human health, have become one of the hot spots in the field of environmental studies in recent years. Currently most studies mainly focus on pollution characteristics such as types and concentrations of antibiotic resistance genes in the water, soil and sediment. However, studies at home and abroad on the antibiotic resistance genes in the atmospheric aerosols were relatively less. Using the real-time fluorescent quantitative PCR and 16S rDNA techniques, in combination with the field sampling and laboratory analysis, with atmospheric PM2.5 and PM10 in different sites of broiler feedlots environments as the research object to establish methods of screening, qualitative and quantitative characterization of tetracycline resistance genes and sulfonamides resistance genes to acquire the characteristics of types, pollution level and regional distribution of typical antibiotic resistance genes in the PM2.5 and PM10 of livestock farms environments. Screening, identification, diversity and the drug resistance level of the antibiotic resistant bacteria were carried out based on antibiotic resistance selective medium to illustrate the distribution characteristics and mutual relations of antibiotic resistance genes and the resistant bacteria in different sizes of atmospheric particulate matters PM2.5 and PM10. Project research results will provide theoretical basis for quantitative characterization, ecological security evaluation and pollution control of antibiotic resistance genes and resistant bacteria in atmospheric environment.

抗生素抗性基因作为一种新型污染物，对人类健康构成威胁，已成为近年来环境研究领域的热点之一。目前多数研究主要关注水、土壤和沉积物中抗生素抗性基因的种类和浓度等污染特征，然而国内外对大气气溶胶中的抗生素抗性基因的研究相对较少。本研究拟采用实时荧光定量PCR和16S rDNA等技术，野外采样和实验室分析相结合，以不同肉鸡养殖场不同点位大气气溶胶中的PM2.5和PM10为研究对象，建立四环素类抗性基因和磺胺类抗性基因的筛选和定性定量表征方法，揭示养殖环境PM2.5和PM10中典型抗生素抗性基因的种类、污染水平及传播规律；通过抗生素抗性选择性培养基开展抗性细菌的筛选、鉴定和多样性以及和耐药性水平研究，阐明不同粒径的大气颗粒物中抗生素抗性基因与抗性细菌的分布特性和相互关系。项目研究成果将为大气环境中抗性基因和抗性细菌的定量表征、生态环境安全评价和污染控制提供理论依据。

抗生素抗性基因（antibiotic resistance genes，ARGs）和抗生素耐药菌（antibiotic resistance bacteria，ARB）的环境污染主要是由于抗生素的过度使用和滥用，进而也降低了抗生素对人类和动物体内多种致病菌的治疗潜力。畜禽粪便通常被认为是抗生素、ARB和ARGs的重要贮存库，随着粪便的排泄，加速了抗生素耐药性在环境中的传播。因此，本课题针对常州集约化肉鸡饲养场PM2.5、粪便和土壤样本，研究其ARGs丰度和多样性、细菌群落结构及ARB分布情况。具体结论如下：.（1）磺胺类抗性基因、大环内酯类抗性基因和四环素类抗性基因在肉鸡饲养场PM2.5、粪便和土壤样品中检出丰度较高。在肉鸡饲养的微环境中，粪便是饲养舍内PM2.5中ARGs的重要来源。Int1与ARGs呈显著正相关，促进了ARGs在不同环境介质之间传播。肉鸡饲养场环境中PM2.5可作为多药耐药性的储库，其中int1和ARGs的暴露量和每日摄入量较高。.（2）冗余分析结果表明肉鸡饲养场不同ARGs与细菌群落的作用关系相似，不同环境介质中ARGs具有类似命运，而优势细菌会在肉鸡饲养场抗性改变中扮演重要作用。共现模式分析结果表明多种ARGs会被葡萄球菌属（Staphylococcus）、拟杆菌属（Bacteroides）和Jeotgalicoccus携带，Staphylococcus作为典型的人类致病菌，其风险更大。.（3）肉鸡饲养场土壤、粪便、舍外PM2.5和舍内PM2.5中多重耐药比率分别为38.46%、100%、33.33%、100%。.本课题对集约化肉鸡饲养场舍内PM2.5、粪便和土壤中ARGs、细菌群落和ARB的研究结果可为集约化家禽饲养环境中ARGs的传播及环境风险提供研究基础, 并评价集约化饲养场PM2.5对人体健康和环境污染的潜在危害.