摘要

      污水处理厂废水是抗生素耐药基因（ARGs）向自然生态系统扩散的热点。细菌抗性（ARG集合在一个宏基因组中）分析提供了抗菌抗性动力学的线索。然而，病毒和囊泡常常被忽视。在这里，我们讨论了在自然条件下从一个代表性的废水中产生的细菌、病毒和囊泡抗性，并用多粘菌素进行了修正，多粘菌素被用作最后的抗生素。元基因组学显示，天然的原核抗性是巨大的（9000个ARG-hits/Gb元基因组）和多样的，而病毒抗性是两个数量级低（50个ARG-hits/Gb元基因组）表明病毒很少编码ARGs。在多粘菌素修正后，数据显示在微生物群中没有ARG的富集-包括对多粘菌素的富集。值得注意的是，微生物群对多粘菌素的反应是大量释放假定的囊泡（比对照组增加三倍），这可能被用作降低抗生素浓度的“陷阱”。有趣的是，尽管多粘菌素抗性基因（PRGs）在微生物组中很少见（占总ARG的0.018%），但在病毒和囊泡组分中，PRGs更为丰富（占总ARG的0.5%-0.8%）。我们的数据表明，囊泡可能在传播抗生素耐药性方面发挥更积极的作用。

       Wastewater treatment plants effluents are considered as hotspots for the dispersion of antibiotic resistance genes (ARGs) into natural ecosystems. The bacterial resistome (ARG collection in a metagenome) analyses have provided clues on antibacterial resistance dynamics. However, viruses and vesicles are frequently ignored. Here, we addressed the bacterial, viral and vesicle resistomes from a representative wastewater effluent in natural conditions and amended with polymyxin, which is used as a last resort antibiotic. Metagenomics showed that the natural prokaryotic resistome was vast (9000 ARG hits/Gb metagenome) and diverse, while viral resistome was two orders of magnitude lower (50 ARG hits/Gb metagenome) suggesting that viruses rarely encoded ARGs. After polymyxin amendment, data showed no ARG enrichment - including to polymyxin - in the microbiome. Remarkably, microbiomes responded to polymyxin with a vast release of putative vesicles (threefold increase compared with the control), which might be used as 'traps' to decrease the antibiotic concentration. Intriguingly, although polymyxin resistance genes (PRGs) were rare in the microbiome (0.018% of total ARG found), in the viral and vesicle fractions, PRGs were more abundant (0.5%-0.8% of total ARG found). Our data suggest that vesicles could have a more active role in the context of transmission of antibiotic resistances.