【摘要】 研究了南京某城市污水处理厂MCR-1基因及其携带菌的污染特征,从MCR-1的分布特征、影响因素及MCR-1携带菌的耐药特征等方面综合评价.结果发现MCR-1随处理流程丰度下降,去除率达83.6%,但其相对丰度在出水中显著升高,剩余污泥中含有高浓度MCR-1,浓度达2.88×1012copies/L.粘菌素耐药菌同样沿处理流程逐渐降低,出水降至53CFU/mL,去除率达99.98%,但在剩余污泥中浓度高达2.04×105CFU/mL.相关性分析发现MCR-1丰度与氨氮含量呈正相关,而相对丰度与COD、总氮和硝酸盐含量呈负相关.耐药特征分析表明曝气池(CAST、MSBR)和曝气生物流化池(ABFT)中MCR-1携带菌可耐受较高浓度粘菌素,且污水处理使MCR-1携带菌对粘菌素的耐受能力提高.表明污水处理流程不但无法完全去除MCR-1及其携带菌,且导致耐药性风险提高.本研究可为评价污水中以MCR-1为代表的超级抗性基因的环境风险提供参考.更多还原

【Abstract】 The study investigated the pollution characteristics of MCR-1 and MCR-1 hosting bacteria in a municipal wastewater treatment plant in Nanjing, China. Their distribution and influence factors, as well as antibiotic resistance characteristics, were comprehensively assessed. The results indicated that the MCR-1 abundance decreased obviously along with the treatment process, with the reduction efficiency of 83.6%. However, its relative abundance increased significantly in the treated effluent. High amount of MCR-1 was detected in biosolids, with concentration of up to 2.88×1012 copies/L. On the other hand, the concentration of colistin resistant bacteria also decreased gradually along with the treatment process. Their concentration decreased to 53 CFU/mL in the final effluent, with the reduction efficiency of 99.98%, but up to 2.04×105 CFU/mL were detected in biosolids. According to the correlation analysis, MCR-1 abundance positively correlated with ammonia concentration, while the relative abundance of MCR-1 showed negative correlation with COD, TN and NO3--N concentration. The antibiotic resistance characteristics analysis indicated that MCR-1 hosting bacteria in the activated sludge system(CAST and MSBR) and aeration biological fluid tank(ABFT) were tolerant to significantly higher colistin concentration relative to other sites. Additionally, the level of MCR-1 hosting bacteria tolerant to colistin was enhanced by the treatment process, which implied that the wastewater treatment process could not completely reduce MCR-1 and MCR-1 hosting bacteria, and even lead to the increase of their potential risks. The study will provide implications for assessing the environmental risks of MCR-1 represented super antibiotic resistant genes.更多还原