摘要

       在这项研究中，我们使用宏基因组学方法检测了猪饲养场废水处理前后细菌和噬菌体所具有的抗生素抗性基因 (ARG) 的类型。我们发现所有水样中细菌 DNA 中 ARG 的相对丰度显着高于噬菌体 DNA（> 10.6 倍），废水处理并未显着改变细菌或噬菌体相关 ARG 的相对丰度。我们根据它们赋予抗性的抗生素类别进一步检测了不同类型 ARG 的分布和多样性，四环素抗性基因是最丰富的抗性基因，噬菌体更有可能携带 ATP 结合盒转运蛋白家族和核糖体保护基因。此外，还在噬菌体群体中检测到粘菌素抗性基因mcr-1。在评估噬菌体在不同组 ARG 中传播的贡献时，β-内酰胺酶抗性基因尽管丰度较低，但具有相对较高的传播能力。这些发现可能表明，噬菌体不仅可以作为 ARG 的重要储存库，而且还可以在猪饲养场废水中携带特定的 ARG，并且这种现象与环境无关。

       In this study, we examined the types of antibiotic resistance genes (ARGs) possessed by bacteria and bacteriophages in swine feedlot wastewater before and after treatment using a metagenomics approach. We found that the relative abundance of ARGs in bacterial DNA in all water samples was significantly higher than that in phages DNA (>10.6-fold), and wastewater treatment did not significantly change the relative abundance of bacterial- or phage-associated ARGs. We further detected the distribution and diversity of the different types of ARGs according to the class of antibiotics to which they confer resistance, the tetracycline resistance genes were the most abundant resistance genes and phages were more likely to harbor ATP-binding cassette transporter family and ribosomal protection genes. Moreover, the colistin resistance gene mcr-1 was also detected in the phage population. When assessing the contribution of phages in spreading different groups of ARGs, β-lactamase resistance genes had a relatively high spreading ability even though the abundance was low. These findings possibly indicated that phages not only could serve as important reservoir of ARG but also carry particular ARGs in swine feedlot wastewater, and this phenomenon is independent of the environment.

https://www.frontiersin.org/articles/10.3389/fmicb.2018.02474/full