摘要

      越来越多的证据表明，环境因素在影响抗药性基因（ARGs）的传播和抗药性人类病原体的传播方面起着关键作用。然而，我们对导致抗生素耐药性发展和传播的生态和进化环境因素缺乏了解。在这里，我们利用高通量定量PCR技术对61份采集自海洋和河滩的土壤样品中的ARGs进行了分析，这些土壤样品是人类活动的热点和潜在的环境ARGs向人类病原体传播的平台。我们确定了影响这些生态系统中ARGs多样性、丰度和组成的主要非生物和生物因素。共检测到110个对8种主要抗生素产生耐药性的arg。核心耐药菌主要为β-内酰胺类和多药耐药，占ARGs总丰度的66.9%。对多种药物耐药的oprJ基因是在所有样本中检测到的最普遍的ARG亚型。总ARGs和岩心电阻率的相对丰度与盐度相关特性（包括电导率、钠和氯化物浓度）显著相关。随机森林分析和结构方程模拟表明，在考虑多种驱动因素后，盐度是调节滩涂土壤ARGs分布格局的最重要因素。这些结果表明，滩涂土壤是富含ARGs的储层，盐分是形成土壤抗逆性分布格局的主要因素。

       Growing evidence points to the pivotal role of the environmental factors in influencing the transmission of antibiotic resistance genes (ARGs) and the propagation of resistant human pathogens. However, our understanding of the ecological and evolutionary environmental factors that contribute to development and dissemination of antibiotic resistance is lacking. Here, we profiled a wide variety of ARGs using the high-throughput quantitative PCR analysis in 61 soil samples collected from ocean and river beaches, which are hotspots for human activities and platforms for potential transmission of environmental ARGs to human pathogens. We identified the dominant abiotic and biotic factors influencing the diversity, abundance and composition of ARGs in these ecosystems. A total of 110 ARGs conferring resistance to eight major categories of antibiotics were detected. The core resistome was mainly affiliated into β-lactam and multidrug resistance, accounting for 66.9% of the total abundance of ARGs. The oprJ gene conferring resistance to multidrug was the most widespread ARG subtype detected in all the samples. The relative abundances of total ARGs and core resistome were significantly correlated with salinity-related properties including electrical conductivity and concentrations of sodium and chloride. Random forest analysis and structural equation modelling revealed that salinity was the most important factor modulating the distribution patterns of beach soil ARGs after accounting for multiple drivers. These findings suggest that beach soil is a rich reservoir of ARGs and that salinity is a predominant factor shaping the distribution patterns of soil resistome.

       https://www.sciencedirect.com/science/article/pii/S0048969718303140?via%3Dihub