摘要

    抗生素的存在会对抗生素抗性基因（ARG）和抗生素抗性细菌（ARB）的出现和传播施加巨大的选择压力。然而，对在高抗生素选择压力下对ARG的共选择作用，ARG的迁移性和ARG宿主的鉴定知之甚少。在这里，宏基因组学的组装和分箱方法被用来全面解读ARGs的流行及其潜在的迁移性以及宿主在处理抗生素生产废水的活性污泥反应器中。我们发现在抗生素治疗中不同类型的ARGs的丰度差异很大，并且一定的抗生素压力促进了对非相应类型ARGs的共选。抗生素选择压力显着提高了质粒介导的ARG的含量和比例（57.9％），比染色体编码的ARGs更为普遍（19.2％）。结果表明质粒和染色体具有携带不同类型的ARG的趋势。而且，ARG和MGE的更高共现频率表明，抗生素增强了质粒，整合和结合元件介导的ARGs的迁移潜力。在估计质量很高的689个元基因组组装基因组（MAG）中，有119个MAG分配给了9个细菌菌群，被确定为ARG宿主，而33个MAGs表现出对抗生素的多重耐药性。某些ARG类型倾向于由某些细菌携带（例如Burkholderiaceae家族携带的杆菌肽抗性基因），因此显示出明显的宿主特异性模式。这项研究增进了对ARGs的迁移性和宿主的理解，并提供了对抗生素耐药性风险评估和管理的重要见解。

    The presence of antibiotics can exert significant selection pressure on the emergence and spread of antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB). However, co-selection effects for ARGs, the mobility of ARGs and the identification of ARG hosts under high antibiotic selection pressures are poorly understood. Here, metagenomic assembly and binning approaches were used to comprehensively decipher the prevalence of ARGs and their potential mobility and hosts in activated sludge reactors treating antibiotic production wastewater. We found the abundance of different ARG types in antibiotic treatments varied greatly and certain antibiotic pressure promoted the co-selection for the non-corresponding types of ARGs. Antibiotic selection pressures significantly increased the abundance and proportions of ARGs mediated by plasmids (57.9%), which were more prevalent than those encoded in chromosomes (19.2%). The results indicated that plasmids and chromosomes had a tendency to carry different types of ARGs. Moreover, higher co-occurrence frequency of ARGs and MGEs revealed that antibiotics enhanced the mobility potential of ARGs mediated by both plasmids and integrative and conjugative elements. Among the 689 metagenome-assembled genomes (MAGs) with high estimated quality, 119 MAGs assigning to nine bacterial phyla were identified as the ARG hosts and 33 MAGs exhibited possible multi-resistance to antibiotics. Some ARG types tended to be carried by certain bacteria (e.g. bacitracin resistance genes carried by the family Burkholderiaceae) and thus showed a pronounced host-specific pattern. This study enhances the understanding of the mobility and hosts of ARGs and provides important insights into the risk assessment and management of antibiotic resistance.

    https://www.sciencedirect.com/science/article/abs/pii/S004313542030854X