摘要

       堆肥已被广泛用于将牲畜粪便转化为有机肥料。然而，牲畜粪便含有各种污染物，包括抗生素和抗生素抗性基因 (ARG)。在这里，我们调查了商业牲畜粪便堆肥过程中抗生素抗性组的变化及其影响因素。结果表明，堆肥可有效降低ARGs和可移动基因元素（MGEs）的相对丰度。作为堆肥样品中的优势门，ARGs 的关键潜在细菌宿主是放线菌，如未分类的白杆菌、分枝杆菌和热单孢菌。同时，嗜肺军团菌、腐生葡萄球菌、杜克雷嗜血杆菌和 Siccibacter turicensis 可能是 ARG 的关键潜在致病宿主，因为它们与 ARG 亚型共存。冗余分析表明，堆肥过程中 ARGs 的耗散与水分等各种环境因素有关。细菌演替以及杀生物剂和金属抗性基因（BMRGs）的特征是在粪便堆肥过程中构建抗生素抗性组的决定因素。然而，堆肥产品中ARGs和病原体的残留可能在施肥后仍然对人类和作物构成风险。

       Composting has been widely used to turn livestock manure into organic fertilizer. However, livestock manure contains various contaminants including antibiotics and antibiotic resistance genes (ARGs). Here we investigated the variation of antibiotic resistome and its influencing factors during a commercial livestock manure composting. The results showed that composting could effectively reduce the relative abundance of ARGs and mobile genic elements (MGEs). As the dominant phylum in the composting samples, the key potential bacterial host of ARGs were Actinobacteria such as Leucobacter, Mycobacterium and Thermomonosporaceae unclassified. Meanwhile, Legionella pneumophila, Staphylococcus saprophyticus, Haemophilus ducreyi and Siccibacter turicensis may be the key potential pathogenic host of ARGs because of their co-occurrence with ARG subtypes. Redundancy analysis showed that the dissipation of ARGs during composting was linked to various environmental factors such as moisture. Bacterial succession as well as profile of biocide and metal resistance genes (BMRGs) were the determinants which constructed the antibiotic resistome during manure composting. However, the residues of ARGs and pathogens in compost products may still pose risks to human and crops after fertilization.

https://www.sciencedirect.com/science/article/pii/S0160412019333057