摘要

      目前，高浓度抗生素对活性污泥（AS）过程中微生物群和耐药基因（ARGs）的影响还没有很好的表征。采用基于16sr RNA基因高通量测序和宏基因组分析的方法，对6种不同浓度抗生素对微生物群落和ARGs的影响进行了研究。抗生素的存在显著降低了微生物多样性，引起了微生物群落结构的巨大变化，并对节杆菌、Thauera、Geothrix、Rudaea、Aridibacter、conexiber、Terrimonas等潜在耐药菌（ARB）的富集产生了选择性的压力，高的抗生素选择压力增加了ARGs的丰度，但同时降低了ARGs的数量。共检测到491个ARG亚型，隶属于20个ARG亚型，卡那霉素处理的ARG丰度最高。共有54个ARGs亚型，占总ARGs丰度的66.7%-99.6%。在特定的抗生素治疗下，相应的和非相应的ARGs的丰度增加，显示了抗生素选择压力的副作用。微生物群落可能在ARGs的组成中起重要作用。网络分析表明，ARGs的内型和外型均表现出较高的非随机共现率，推测有18个属可能是多个ARGs的寄主。本研究揭示了高浓度抗生素废水AS处理过程中微生物群落与ARGs的分布及相互关系，为控制ARB和ARGs的发展和传播提供了有益的指导。

       Currently, the effects of high antibiotic concentrations on the performance of microbiota and antibiotic resistance genes (ARGs) in activated sludge (AS) process are not well characterized. Lab-scale batch reactors were performed to evaluate the dynamics of microbial community and ARGs in response to six antibiotics at different concentrations using high-throughput sequencing-based 16S rRNA gene and metagenomic analyses. The presence of antibiotics remarkably decreased the microbial diversity, caused a great change of the microbiota structure, and exerted a selective pressure on the enrichment of potential antibiotic resistant bacteria (ARB), such as Arthrobacter, Thauera, Geothrix, Rudaea, Aridibacter, Conexibacter, Terrimonas, etc. High antibiotic selective pressures increased ARG abundance but simultaneously reduced ARG number. In total, 491 ARG subtypes belonging to 20 ARG types were detected and kanamycin treatment showed the highest ARG abundances. A core set of 54 ARG subtypes that accounted for 66.7%-99.6% of the total ARG abundances were shared by all samples. The increase of the abundances of both corresponding and non-corresponding ARGs under a specific antibiotic treatment revealed the collateral effects of antibiotic selective pressure. Microbial community may play an important role in the composition of ARGs. Network analysis indicated that both internal-type and external-type of ARGs exhibited higher non-random co-occurrence incidences and 18 genera were speculated as the possible hosts for multiple ARGs. This study deciphered the profiles and relationships between microbial community and ARGs in AS process treating wastewater with high antibiotic concentrations and could provide helpful guidance for controlling the development and dissemination of ARB and ARGs.

       https://www.sciencedirect.com/science/article/abs/pii/S0043135418310522?via%3Dihub