【摘要】 微塑料（MPs）和抗生素耐药基因（ARGs）是共存于污水处理厂中的典型新污染物.MPs已被证明能够改变污泥中ARGs的分布模式，但其对污水中胞外ARGs（fe ARGs）的影响及机制仍不清楚.采用荧光定量PCR技术探究了典型MPs（聚苯乙烯PS）暴露60 d后污水中fe ARGs（包括tet C、tet O、sul1和sul2）的动态变化特征及机制.结果表明，四环素类fe ARGs绝对丰度在nm级和mm级PS暴露下分别降低了28.4%～76.0%和35.2%～96.2%，在μm级PS暴露下变化了-55.4%～122.4%.PS对磺胺类sul1的促进效果呈nm级>μm级>mm级趋势，且ρ（PS）为50 mg·L^-1对sul1丰度扰动幅度更大.磺胺类sul2的相对丰度在μm级和mm级PS暴露后分别削减了25.4%～42.6%和46.1%～90.3%，在nm级PS暴露后增加了1.9～3.9倍；ρ（PS）为50 mg·L^-1对sul2的削减作用高于ρ（PS）为0.5 mg·L^-1.Pearson相关性分析显示，PS暴露下fe ARGs相对丰度与细胞膜通透性和典型可移动遗传元件（int I1）丰度成正相关，与活性氧水平成负相关.研究结果阐明了PS对污水中fe ARGs的影响及其机制，可为污水中MPs与ARGs复合污染的防治提供科学依据.更多还原

【Abstract】 Microplastics （MPs） and antibiotic resistance genes （ARGs） are typical co-existing emerging pollutants in wastewater treatment plants.MPs have been shown to alter the distribution pattern of ARGs in sludge,but their effects on free extracellular ARGs （fe ARGs） in wastewater remain unclear.In this study,we used fluorescence quantitative PCR to investigate the dynamics of fe ARGs （including tet C,tet O,sul1,and sul2） in wastewater and their transition mechanisms after 60 d of exposure to typical MPs （polystyrene,PS）.The results showed that the absolute abundance of tetracycline fe ARGs decreased by 28.4%-76.0%and 35.2%-96.2%,respectively,under nm-level and mm-level PS exposure and changed by-55.4%-122.4%underμm-level PS exposure.The abundance of sul1 showed a trend of nm-level>μm-level>mm-level upon PS exposure,and the changes in sul1abundance was greater withρ（PS）=50 mg·L^-1 exposure.The relative abundance of sul2 was reduced by 25.4%-42.6%and 46.1%-90.3%afterμm-level and mm-level PS exposure,respectively,and increased by 1.9-3.9 times after nm-level PS exposure,and the sul2 showed a higher reduction atρ（PS）=50 mg·L^-1 exposure than that atρ（PS）=0.5 mg·L^-1.The Pearson correlation analysis showed that the relative abundance of fe ARGs during PS exposure was positively correlated with cell membrane permeability and typical mobile genetic elements （int I1） abundance and negatively correlated with reactive oxygen species level.Our findings elucidated the effects and corresponding mechanisms of PS on the growth and mobility of fe ARGs in wastewater,providing a scientific basis for the control of the combined MPs and ARGs pollution in wastewater.更多还原