摘要

    近年来，由于施用动物肥料而引起的土壤抗生素抗性受到极大关注。人们对长期施用肥料的农业土壤中抗生素抗性基因（ARG）的命运知之甚少。在这里，我们使用土壤微观来调查ARGs的耗散和源自蔬菜田的农业土壤中细菌群落的变化，该蔬菜田已经应用了24年的猪粪。在实验室的两年测试期间内，在不同的土壤湿度下，有无生物炭的条件下进行了土壤微观研究。结果表明，连续施用肥料会导致土壤中ARGs的积累，其中ARGs的消散与非肥料改良土壤中的ARGs的消散不同。尽管ARGs的丰度逐渐下降，但它们在土壤中至少保留了两年。同时，土壤水分和生物炭对ARGs的命运有重要影响。 ARGs在水分较高的土壤中的消散速度更快。生物炭修正案有助于维持细菌多样性。在两年的模拟实验中，生物炭提高了土壤ARG的保留率，因为它们缓慢散布在经过生物炭改良的土壤中。微生物群落的继承可能维持了ARGs的转移和适应力。这项研究提供了在施用肥料的农业土壤中抗生素抗性基因消散的真知灼见。

    Soil antibiotic resistance due to animal manure application is of great concern in recent years. Little is known about the fate of antibiotic resistance genes (ARGs) in agricultural soils associated with long-term manure application. Here we used soil microcosms to investigate the dissipation of ARGs and the change of bacterial community in agricultural soil originated from a vegetable field which had received 24 years' swine manure application. Soil microcosms were conducted at different soil moistures and with or without biochar over a testing period of two years in lab. Results showed that continuous manure application induced an accumulation of ARGs in soil, wherein the dissipation of ARGs differed from those in non-manure amended soil. ARGs persisted in soils at least two years, although their abundance declined gradually. Meanwhile, soil moisture and biochar had significant impact on the fate of ARGs. ARGs dissipated faster in soil with higher moisture. Biochar amendment contributed to the maintenance of bacterial diversity. Within the two years of simulation experiment, biochar enhanced soil ARG retention as they dissipated slowly in the soil amended with biochar. Succession of microbial community may have sustained the transfer and resilience of ARGs. This study provides insight into the dissipation of antibiotic resistance genes in manure-applied agricultural soil.

    https://www.sciencedirect.com/science/article/abs/pii/S004896972102653X