摘要
      在人为压力的驱动下，抗生素抗性基因（ARGs）可以从环境抗性组转移到人类共生体甚至病原体中。ARGs通过水生生态系统的运输至关重要，已引起人们的关注。在这里，我们使用宏基因组和装箱来比较原始河流和受人为影响的河流之间的ARGs谱、它们与金属抗性基因（MRG）和可移动遗传元件（MGE）的共存情况以及它们的宿主，并探索人类活动诱导的ARG传播的生态机制。从原始沉积物到污染沉积物，大环内酯林可酰胺链脲菌素、万古霉素、β-内酰胺和磺酰胺抗性基因的相对丰度沿着环境梯度显著增加，这表明人为影响有助于某些ARG的出现和传播。在巴河下游，携带一个以上ARG的大陆群的比率较高，这表明人为污染有利于多种ARG的共存。人为压力也增加了优势宿主的相对丰度，包括绿弯菌门、厚壁菌门和Euryarchaeota。在Ba河下游，携带多种ARGs和ICEs的timonensis Romboutsia被成功回收，通过影响肠道微生物群的代谢，对人类健康构成严重威胁。在Ba河下游也发现了携带多种ARGs、MRGs和ICEs的古菌所属的索氏甲烷菌。偏最小二乘路径模型显示，MGE是诱导ARG谱的最主要因素，并且可以通过与MRG的共转移来富集抗生素耐药性。此外，环境因素可以通过首先影响ARG的宿主来间接影响ARG概况。
Abstract
Driven by anthropogenic pressure, Antibiotic resistance genes (ARGs) could transfer from the environmental resistome into human commensals or even pathogens. The transport of ARGs through aquatic ecosystems is crucial and has attracted attention. Here, we employed metagenomic and binning to compare ARGs profiles, their co-occurrence with metal resistance genes (MRGs) and mobile genetic elements (MGEs), and their hosts between pristine and anthropogenic influenced rivers and explore the ecological mechanisms underlying the dissemination of ARGs induced by anthropogenic activities. The significantly increased relative abundance of macrolide-lincosamide-streptogramins, vancomycin, β-lactam and sulfonamide resistance genes along the environmental gradient from pristine to polluted sediments implied that anthropogenic impact aided the emergence and dissemination of certain ARGs. At the lower reach of the Ba River, the higher ratios for contigs carrying more than one ARG suggested that anthropogenic pollution favored the co-occurrence of multiple ARGs. Anthropogenic pressures also increased the relative abundance of advantaged hosts, including Chloroflexi, Firmicutes and Euryarchaeota. At the lower reach of Ba River, Romboutsia timonensis carrying multiple ARGs and ICEs were successfully recovered, posing a serious threat to human health by affecting the metabolism of gut microbiomes. And Methanothrix soehngenii affiliated to archaea carrying multiple ARGs, MRGs and ICEs were also recovered from the lower Ba River. The partial least squares path modeling revealed that MGEs were the most predominant factors inducing the ARG profiles, and the antibiotic resistance could be enriched by co-transfer with MRGs. Furthermore, environmental factors could impact the ARG profiles indirectly by first influencing the ARGs’ hosts.

https://www.sciencedirect.com/science/article/abs/pii/S0166445X22001473