摘要

堆肥作为一种有机肥料应用于农业生态系统之前，已被认为是消除畜禽粪便中抗生素残留和病原体的潜在策略。然而，堆肥对畜禽粪便中抗生素抗性基因( ARGs )的影响及其在施用堆肥后的时间序列尚不清楚。研究了好氧堆肥处理对牛粪抗性谱的影响，并通过构建实验室微观系统，比较了有机肥和堆肥处理对农田土壤中多种ARGs时间序列的影响。高通量定量PCR芯片在所有土壤、粪便和堆肥样品中总共检测到144个ARGs，其中大环内酯-林肯酰胺-链脲菌素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。堆肥显著降低了牛粪中ARG和可移动遗传元素的多样性和相对丰度。在120天的微生态培养中，有机肥处理土壤中ARG的多样性和丰富度显著高于堆肥处理土壤。随着时间的推移，所有粪便和堆肥处理过的土壤的抗生素抗性水平迅速下降，而且来源跟踪分析显示，粪便和堆肥产生的细菌群落具有类似的时间模式。网络分析表明，有机肥处理的土壤中ARGs和MGEs之间的相互作用/关联强度大于堆肥处理的土壤，表明堆肥处理的土壤中ARGs的迁移潜力较低。研究结果表明，牛粪好氧堆肥是一种有效降低有机废弃物土地利用中抗生素抗性传播风险的方法。

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 尾-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/pii/S0048969717323707