摘要

      水生生态系统是抗生素耐药菌（ARB）和抗生素耐药基因（ARG）的传播途径和贮存库。在本研究中，我们探讨了细菌孢子虫在水生生态系统中作为ARGs传播载体的作用。孢子虫在操作上被定义为细菌群落的弹性部分，能够承受严酷的提取处理，消除整个细菌群落中容易溶解的部分。孢子虫已被确认为人类微生物群的关键组成部分，因此可能是ARGs在人类受影响环境中传播的关键因素。在日内瓦湖的一个区域，沉积物中的精氨酸的积累先前与处理废水的沉积有关，该区域被选为研究tet（W）和sul1的传播，这两个基因分别赋予四环素和磺胺的抗性。通过对孢子虫体（sporobiota的基因集合）中这些ARG的丰度及其与群落组成和环境参数的相关性分析，表明ARG可以以sporobiota为传播载体在环境中传播。由于与tet（W）频率（ARG拷贝数/ng-DNA）有很强的相关性，一个高度丰富的附属于梭菌属的OTU被认为是tet（W）传播的潜在特异载体。孢子虫的高扩散率、长期存活和潜在的复活是ARG在环境中传播和持续存在的一个严重问题。

       Aquatic ecosystems serve as a dissemination pathway and a reservoir of both antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARG). In this study, we investigate the role of the bacterial sporobiota to act as a vector for ARG dispersal in aquatic ecosystems. The sporobiota was operationally defined as the resilient fraction of the bacterial community withstanding a harsh extraction treatment eliminating the easily lysed fraction of the total bacterial community. The sporobiota has been identified as a critical component of the human microbiome, and therefore potentially a key element in the dissemination of ARG in human-impacted environments. A region of Lake Geneva in which the accumulation of ARG in the sediments has been previously linked to the deposition of treated wastewater was selected to investigate the dissemination of tet(W) and sul1, two genes conferring resistance to tetracycline and sulfonamide, respectively. Analysis of the abundance of these ARG within the sporobiome (collection of genes of the sporobiota) and correlation with community composition and environmental parameters demonstrated that ARG can spread across the environment with the sporobiota being the dispersal vector. A highly abundant OTU affiliated with the genus Clostridium was identified as a potential specific vector for the dissemination of tet(W), due to a strong correlation with tet(W) frequency (ARG copy numbers/ng DNA). The high dispersal rate, long-term survival, and potential reactivation of the sporobiota constitute a serious concern in terms of dissemination and persistence of ARG in the environment.

       https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6015491/