摘要
      再生废水灌溉对抗生素抗性基因（ARGs）在土壤中传播的影响受到无数生物和非生物因素的调节，其相对意义尚不明确。我们使用霰弹枪宏基因组测序，在两个不同种植系统的温室中，用地下水（GW）、RW或交替用GW和RW灌溉16年后，比较了土壤中的微生物群落、与微生物对抗生素、杀生物剂和金属的耐药性相关的基因组合，以及插入序列（IS）。结果表明，种植制度对IS和抗性基因的影响大于灌溉制度。这种影响与土壤中铜、汞和环丙沙星的浓度密切相关。连续RW灌溉与交替GW和RW灌溉之间的土壤ARG剖面没有显著差异。变形菌门、放线菌门和厚壁菌门以及数量有限的IS与检测到的ARG密切相关。大多数ARGs被发现通过外排泵的机制与金属和杀生物剂抗性基因共存。这些发现强调了理解和改善作物管理对减缓ARGs在RW灌溉土壤中传播的重要性。
Abstract
The effects of reclaimed wastewater (RW) irrigation on the spread of antibiotic resistance genes (ARGs) in soil is modulated by a myriad of biotic and abiotic factors and their relative significance remains vague. We compared microbial communities, assemblages of genes associated with microbial resistance to antibiotics, biocides and metals, and insertion sequences (ISs) in soils following 16 years of irrigation with groundwater (GW), RW or alternately with GW and RW in two greenhouses with different cropping systems, using shotgun metagenome sequencing. The results showed that cropping system exerted greater influence than irrigation on the profile of ISs and resistance genes. This influence was most strongly associated with concentrations of copper, mercury and perfloxacin in the soils. There was no significant difference in soil ARG profiles between continuous RW irrigation and alternating GW and RW irrigation. Proteobacteria, Actinobacteria and Firmicutes and a limited number of ISs were closely associated with the detected ARGs. Most ARGs were found to co-occur with metal and biocide resistance genes through the mechanism of efflux pumps. These findings highlight the significance of understanding and improving crop management in mitigating the dissemination of ARGs in soils irrigated with RW.

https://www.sciencedirect.com/science/article/abs/pii/S0304389421030156