摘要

       抗生素耐药基因（ARGs）被认为是环境污染物。在原始环境中对ARGs进行全面的鉴定对于了解抗生素耐药性的演变是至关重要的。在这里，我们使用宏基因组方法分析了从相对原始的南极洲采集的土壤样品中的ARGs。我们鉴定了南极土壤中与12个抗生素类相关的79个亚型，其中与多药和多肽相关的ARGs占优势。南极土壤中ARGs的组成、丰度和潜在迁移性与活性污泥、鸡粪和猪粪中的ARGs有显著差异。在南极土壤中，ARG亚型（如bacA、ceoB、dfrE、mdtB、amrB和acrB）比其它亚型丰富。约60%的ARGs通过外排机制产生耐药性，质粒上可能存在少量ARGs（∼16%）。从南极土壤中分离出的可培养菌群对临床治疗中常用的大多数抗生素始终敏感。可培养种携带的amrB和ceoB在临床上对氨基糖苷类和氟喹诺酮类药物没有表现出耐药性。我们的结果表明，抗生素的广泛使用可能有助于发展更高的抗生素耐药性和流动性。

       Antibiotic resistance genes (ARGs) are considered environmental pollutants. Comprehensive characterization of the ARGs in pristine environments is essential towards understanding the evolution of antibiotic resistance. Here, we analyzed ARGs in soil samples collected from relatively pristine Antarctica using metagenomic approaches. We identified 79 subtypes related to 12 antibiotic classes in Antarctic soils, in which ARGs related to multidrug and polypeptide were dominant. The characteristics of ARGs in Antarctic soils were significantly different from those in active sludge, chicken feces and swine feces, in terms of composition, abundance and potential transferability. ARG subtypes (e.g., bacA, ceoB, dfrE, mdtB, amrB, and acrB) were more abundant than others in Antarctic soils. Approximately 60% of the ARGs conferred antibiotic resistance via an efflux mechanism, and a low fraction of ARGs (∼16%) might be present on plasmids. Culturable bacterial consortiums isolated from Antarctic soils were consistently susceptible to most of the tested antibiotics frequently used in clinical therapies. The amrB and ceoB carried by culturable species did not express the resistance to aminoglycoside and fluoroquinolone at the levels of clinical concern. Our results suggest that the wide use of antibiotics may have contributed to developing higher antibiotic resistance and mobility.

        https://www.sciencedirect.com/science/article/abs/pii/S0147651319303719?via%3Dihub