摘要
动物粪肥的土地施用是一种常见的农业应用，可能导致抗生素抗性基因（ARG）在环境中的扩散和繁殖。然而，从未系统地比较过施用不同来源粪肥后农业生态系统中抗药性的变化情况。通过土壤微生态培养，比较添加和不添加抗生素泰乐菌素的家禽，牛和猪粪对土壤ARG时间变化的影响。高通量定量PCR总共检测到185个独特的ARG，其中大环内酯 - 林可酰胺 - 链霉抗生素B抗性是最常见的ARG类型。在施用添加泰乐菌素的粪肥和肥料后，ARG的多样性和丰度显着增加，在猪和禽粪肥处理中观察到的效果比牛粪处理更显着。随着时间的推移，所有肥料土壤中的抗生素耐药性水平逐渐降低，但在130天的培养后，用猪和家禽粪肥处理的土壤中的ARGs含量仍然显着高于未处理的土壤。泰乐菌素改良土壤的ARGs含量始终表现出比仅用粪肥处理的土壤ARGs含量更高，这表明施用抗生素对土壤ARGs的选择压力很大。 ARGs的相对丰度与整合酶和转座酶基因呈显着正相关，表明ARGs在粪肥和泰乐菌素处理土壤中的水平转移潜能。我们的研究结果证明，应用猪粪和家禽粪便可能比施用牛粪更能富集土壤中的ARGs，这就需要在土地施用之前对原始动物粪肥进行适当处理，以尽量减少环境中ARGs的扩散。
Land application of animal manure is a common agricultural practice potentially leading to dispersal and propagation of antibiotic resistance genes (ARGs) in environmental settings. However, the fate of resistome in agro-ecosystems over time following application of different manure sources has never been compared systematically. Here, soil microcosm incubation was conducted to compare effects of poultry, cattle and swine manures spiked with or without the antibiotic tylosin on the temporal changes of soil ARGs. The high-throughput quantitative PCR detected a total of 185 unique ARGs, with Macrolide-Lincosamide-Streptogramin B resistance as the most frequently encountered ARG type. The diversity and abundance of ARGs significantly increased following application of manure and manure spiked with tylosin, with more pronounced effects observed in the swine and poultry manure treatments than in the cattle manure treatment. The level of antibiotic resistance gradually decreased over time in all manured soils but was still significantly higher in the soils treated with swine and poultry manures than in the untreated soils after 130 days’ incubation. Tylosin-amended soils consistently showed higher abundances of ARGs than soils treated with manure only, suggesting a strong selection pressure of antibiotic-spiked manure on soil ARGs. The relative abundance of ARGs had significantly positive correlations with integrase and transposase genes, indicative of horizontal transfer potential of ARGs in manure and tylosin treated soils. Our findings provide evidence that application of swine and poultry manures might enrich more soil ARGs than cattle manure, which necessitates the appropriate treatment of raw animal manures prior to land application to minimise the spread of environmental ARGs.
https://www.sciencedirect.com/science/article/pii/S0269749117324491
