摘要

       堆肥被认为是一种潜在的策略，可以在将牲畜粪便用作农业生态系统中的有机肥料之前消除牲畜粪便中的抗生素残留物和病原体。然而，堆肥对牲畜粪便中抗生素抗性基因 (ARG) 的影响及其在将堆肥应用于土地后的时间序列方面尚不清楚。我们研究了好氧堆肥如何影响牛粪的抵抗力谱，并通过构建实验室微观世界，我们比较了粪肥和堆肥施用于农业土壤对广谱 ARG 的时间序列的影响。高通量定量 PCR 阵列在所有土壤、粪便和堆肥样品中共检测到 144 个 ARG，其中大环内酯-林可酰胺-链霉菌素 B、氨基糖苷类、多药、四环素和 β-内酰胺抗性是最主要的类型。堆肥显着降低了牛粪中 ARG 和移动遗传元件 (MGE) 的多样性和相对丰度。在120天的微观培养中，试验开始时，经粪肥处理的土壤中ARGs的多样性和丰度显着高于堆肥处理土壤。 SourceTracker 分析显示，在所有经过粪便和堆肥处理的土壤中，抗生素抗性水平随着时间的推移迅速下降，加上粪便和堆肥衍生的细菌群落的相似时间模式。网络分析显示，在经过粪便处理的土壤中，ARGs 和 MGEs 之间的相互作用/关联比在堆肥处理的土壤中更强烈，这表明 ARGs 在用堆肥改良的土壤中的流动潜力较低。我们的结果提供证据表明，牛粪有氧堆肥可能是减轻与有机废物土地应用相关的抗生素抗性传播风险的有效方法。

       Composting has been suggested as a potential strategy to eliminate antibiotic residues and pathogens in livestock manure before its application as an organic fertilizer in agro-ecosystems. However, the impacts of composting on antibiotic resistance genes (ARGs) in livestock manure and their temporal succession following the application of compost to land are not well understood. We examined how aerobic composting affected the resistome profiles of cattle manure, and by constructing laboratory microcosms we compared the effects of manure and compost application to agricultural soils on the temporal succession of a wide spectrum of ARGs. The high-throughput quantitative PCR array detected a total of 144 ARGs across all the soil, manure and compost samples, with Macrolide-Lincosamide-Streptogramin B, aminoglycoside, multidrug, tetracycline, and β-lactam resistance as the most dominant types. Composting significantly reduced the diversity and relative abundance of ARGs and mobile genetic elements (MGEs) in the cattle manure. In the 120-day microcosm incubation, the diversity and abundance of ARGs in manure-treated soils were significantly higher than those in compost-treated soils at the beginning of the experiment. The level of antibiotic resistance rapidly declined over time in all manure- and compost-treated soils, coupled with similar temporal patterns of manure- and compost-derived bacterial communities as revealed by SourceTracker analysis. The network analysis revealed more intensive interactions/associations among ARGs and MGEs in manure-treated soils than in compost-treated soils, suggesting that mobility potential of ARGs was lower in soils amended with compost. Our results provide evidence that aerobic composting of cattle manure may be an effective approach to mitigate the risk of antibiotic resistance propagation associated with land application of organic wastes.

https://www.sciencedirect.com/science/article/abs/pii/S0048969717323707