摘要
      极地抗生素耐药性的概况和驱动机制对于探索抗生素耐药性基因（ARGs）的自然进化具有重要意义。在这里，我们评估了南极洲Terra Nova湾不可表达岛上多种介质中抗生素耐药性的概况。水（3.98×106拷贝/L）、土壤（3.41×107拷贝/kg）和企鹅粪（7.04×107拷贝/kg）中细胞内DNA（iARGs）中ARGs的平均浓度高于水（1.99×104拷贝/L），土壤（1.75×106拷贝/kg），企鹅粪（8.02×106拷贝/kg。研究表明，ARGs在不同介质中的传播发生在水中观察到的土壤中约有78.1%的iARGs和企鹅中约有86.7%的iARG，以及土壤中发现的企鹅中约80.7%的iARGs和56.7%的eARGs。自1983年以来，无法表达岛上阿德利企鹅的ARGs年输入量有所增加。杆菌肽、多药和氨基糖苷类抗性基因是水、土壤和企鹅粪便中的主要ARGs。与人类致病菌相关的原发性中危ARGs是多药耐药基因，与可移动遗传元件（MGE）相关的主要低危ARG是氨基糖苷类耐药基因。来自土壤和企鹅的抗生素抗性细菌（ARB）在系统发育上与水生抗生素抗性嗜冷菌相比，与水生抗生素耐药性嗜冷菌更为相关。MGE、ARB、细菌多样性、抗生素和金属可以解释水和土壤之间的总ARG。细胞内MGE是iARGs在水中最重要的原位驱动因素，这反映出水平基因转移可以促进ARGs在水中的传播。企鹅是环境抗生素耐药性的重要非原位驱动因素，这与水和土壤之间的危险ARG有关。这些发现突出了自然驱动因素（如MGE和企鹅）在形成极地环境抗生素耐药性方面的主要作用，提高了我们对环境微生物组进化的理解。
Abstract
Profiles and driving mechanisms of antibiotic resistome in the polar region are important for exploring the natural evolution of antibiotic resistance genes (ARGs). Here, we evaluated the profiles of antibiotic resistome in multiple media on Inexpressible Island, Terra Nova Bay, Antarctica. Average concentrations of ARGs in intracellular DNA (iARGs) among water (3.98 × 106 copies/L), soil (3.41 × 107 copies/kg), and penguin guano (7.04 × 107 copies/kg) were higher than those of ARGs in extracellular DNA (eARGs) among water (1.99 × 104 copies/L), soil (1.75 × 106 copies/kg), and penguin guano (8.02 × 106 copies/kg). It was indicated that the transmission of ARGs across different media occurs with around 78.1% of iARGs from soil and 86.7% of iARGs from penguins observed in water, and 80.7% of iARGs and 56.7% of eARGs from penguins found in soil. Annual inputs of ARGs from Adélie penguins on Inexpressible Island have increased since 1983. Bacitracin, multidrug, and aminoglycoside resistance genes were the main ARGs among water, soil, and penguin guano. Primary medium-risk ARGs associated with human pathogenic bacteria were multidrug resistance genes, and main low-risk ARGs associated with mobile genetic elements (MGEs) were aminoglycoside resistance genes. Antibiotic-resistant bacteria (ARB) from soil and penguins were more phylogenetically related to aquatic antibiotic-resistant mesophiles than aquatic antibiotic-resistant psychrophiles. MGEs, ARB, bacterial diversities, antibiotics, and metals could explain total ARGs between water and soil. Intracellular MGEs were the most significant in-situ driver of iARGs in water, reflecting that horizontal gene transfer could facilitate the spread of ARGs in water. Penguins were important ex-situ drivers of environmental antibiotic resistome, which was linked with risky ARGs between water and soil. These findings highlight the major roles of natural drivers (e.g., MGEs and penguins) in shaping environmental antibiotic resistome in polar areas, improving our understanding of the evolution of environmental microbiome.

https://www.sciencedirect.com/science/article/pii/S266732582200454X