SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China.
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
Environ Int. 2020 Mar;136:105458. doi: 10.1016/j.envint.2020.105458. Epub 2020 Jan 8.
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.
堆肥已被广泛用于将动物粪便转化为有机肥料。然而，动物粪便中含有各种污染物，包括抗生素和抗生素抗性基因（ARGs）。在这里，我们研究了商业动物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，堆肥可以有效降低 ARGs 和移动遗传元件（MGEs）的相对丰度。在堆肥样品中作为主要门的放线菌，如白杆菌属、分枝杆菌属和未分类的 Thermomonosporaceae 等，是 ARGs 的主要潜在细菌宿主。同时，嗜肺军团菌、腐生葡萄球菌、杜克嗜血杆菌和土耳其沙雷氏菌可能是 ARG 亚型的关键潜在致病宿主，因为它们与 ARG 亚型共同出现。冗余分析表明，堆肥过程中 ARGs 的降解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）的组成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 和病原体的残留仍可能在施肥后对人类和作物构成风险。
