摘要

       高浓度的抗生素会对微生物群落施加强大的选择压力，并促进抗生素抗性基因（ARGs）的出现和传播。建立了处理氨苄青霉素、头孢氨苄和氯霉素生产废水的活性污泥反应器，以研究微生物群落、ARGs和移动遗传元件（MGEs）对抗生素的反应。抗生素选择压力显着降低了微生物多样性并改变了微生物群落结构。基于宏基因组分析，共鉴定出隶属于 18 个 ARG 类型的 500 个 ARG 亚型，所有样本共有 63 个 ARG。 ARG 丰度的大幅增加和 ARG 谱的变化与抗生素类型和浓度显着相关。非对应 ARG 类型的明显富集表明目标抗生素具有强烈的共选择效应。此外，宏基因组分析显示出现了 104 个属于不同类型的 MGE，其中 5 个占优势的 MGE 是 tnpA、intI1、tniA、tniB 和 IS91。 ARG-MGE 共现关联暗示了 ARG 的潜在流动性。网络分析还表明，五种 ARG 类型（氨基糖苷类、β-内酰胺、氯霉素、多药和四环素抗性基因）倾向于内部共存，不同 ARG 类型之间明显的共存模式表明存在抗性共选择的潜力。此外，推测 15 个细菌属是不同 ARG 的宿主。本研究全面概述了 ARGs 和 MGEs 的发生，对抗生素耐药性的风险评估和管理具有重要价值。

       High concentrations of antibiotics can exert strong selection pressures on the microbial community and promote the emergence and dissemination of antibiotic resistance genes (ARGs). The activated sludge reactors treating ampicillin, cephalexin and chloramphenicol production wastewater were established to investigate the responses of microbial community, ARGs and mobile genetic elements (MGEs) to antibiotics. Antibiotic selection pressures significantly declined the microbial diversity and changed microbial community structures. Based on metagenomic analysis, a total of 500 ARG subtypes affiliated with 18 ARG types were identified and 63 ARGs were shared by all samples. The substantial increase of ARG abundance and the shifts of ARG profiles were significantly correlated with antibiotic types and concentrations. The evident enrichment of non-corresponding ARG types suggested the strong co-selection effects of the target antibiotics. Additionally, metagenomic analysis revealed the occurrence of 104 MGEs belonging to various types and the five dominant MGEs were tnpA, intI1, tniA, tniB and IS91. The ARG–MGE co-occurrence associations implied the potential mobility of ARGs. Network analysis also demonstrated that five ARG types (aminoglycoside, beta-lactam, chloramphenicol, multidrug and tetracycline resistance genes) tended to co-occur internally and the obvious co-occurrence patterns among different ARG types indicated the potential for resistance co-selection. Moreover, 15 bacterial genera were speculated as the hosts of diverse ARGs. This study provides a comprehensive overview of the occurrence of ARGs and MGEs and is valuable for the risk assessment and management of antibiotic resistance.

https://www.sciencedirect.com/science/article/abs/pii/S0048969720361611