摘要
      受污染的水生环境，特别是那些携带临床感兴趣的抗生素耐药性基因（ARGs）的水生环境对人类健康构成的风险仍存在争议。这是因为我们对环境中抗微生物耐药性的动力学、ARGs传播的选择机制以及可能有利于其回归人类的生态因素的了解有限。1类整合子是ARG传播最有效的平台之一。在这项研究中，我们研究了一个由湖泊-河流-湖泊连续体组成的淡水系统，通过调制宏基因组方法确定了1类整合子及其相关ARG的丰度。在六个月的时间里，使用细菌丰度和群落组成来鉴定1类整合子及其相关ARG的潜在携带者。在接收处理过的废水的河流采样点，1类整合子及其ARG货物的数量要多得多。此外，1类整合子携带对人类健康风险最高的ARG（例如catB基因），特别是编码氨基糖苷类抗性的基因。潜在病原体，如假单胞菌和志贺氏杆菌，与1类整合子相关。湖泊-河流-湖泊系统证明了1类整合子的整合酶基因（intI1）与人为影响之间的明确关系，但也表明了强烈的环境过滤，一旦人类来源的压力源减少，就有利于消除intI1。总的来说，这项研究的结果强调了1类整合子作为人为污染的代表的作用，并表明该遗传平台是氨基糖苷类抗性基因的重要驱动因素，包括对人类健康潜在关注的高风险ARGs。
Abstract
The risk for human health posed by polluted aquatic environments, and especially those carrying antibiotic resistance genes (ARGs) of clinical interest, is still debated. This is because of our limited knowledge of the dynamics of antimicrobial resistance in the environment, the selection mechanisms underlying the spread of ARGs, and the ecological factors potentially favoring their return to humans. The Class 1 integron is one of the most effective platforms for the dissemination of ARGs. In this study we investigated a freshwater system consisting of a lake-river-lake continuum, determining the abundance of class 1 integrons and their associated ARGs by a modulated metagenomic approach. Bacterial abundance and community composition were used to identify the potential carriers of class 1 integrons and their associated ARGs over a period of six months. Class 1 integrons and their ARG cargoes were significantly more abundant in riverine sampling sites receiving treated wastewater. Further, class 1 integrons carried ARGs ranked at the highest risk for human health (e.g., catB genes), in particular, genes encoding resistance to aminoglycosides. Genera of potential pathogens, such as Pseudomonas and Escherichia-Shigella, were correlated with class 1 integrons. The lake-river-lake system demonstrated a clear relationship between the integrase gene of class 1 integrons (intI1) and anthropogenic impact, but also a strong environmental filtering that favored the elimination of intI1 once the human derived stressors were reduced. Overall, the results of this study underline the role class 1 integrons as proxy of anthropogenic pollution and suggest this genetic platform as an important driver of aminoglycoside resistance genes, including high risk ARGs, of potential concern for human health.

https://www.sciencedirect.com/science/article/abs/pii/S0269749122018152