摘要
      畜禽粪便中抗生素抗性基因（ARGs）含量高，对环境和人类健康构成潜在风险。常温堆堆肥和高温堆肥是将牲畜粪便转化为肥料的两种方法。本研究调查了ARGs和可移动遗传元素（MGE）的变化，并揭示了使用两种堆肥方法去除ARGs的潜在机制。堆堆堆肥中ARGs的丰度增加了44倍，其中大环内酯类抗性基因显著增加。相反，在高温堆肥中，ARGs被去除了92%，其中四环素抗性基因减少了97%。ARGs的细菌宿主与ARGs和MGE的变异有关。tetO与堆堆堆肥中种类最多的细菌相关，拟杆菌是主要的宿主细菌。而tetT与嗜热堆肥中种类最多的细菌相关，变形杆菌是主要的宿主细菌。结构方程模型表明，堆堆堆肥中ARGs的富集主要与细菌群落有关，而嗜热堆肥中ARG的去除则直接受到MGE的影响。堆肥温度直接影响ARGs的变化。较高和较低的温度分别显著降低和增加了ARGs和MGEs的丰度水平。
Abstract
The high antibiotic resistance gene (ARGs) contents in livestock manure pose a potential risk to environment and human health. The heap composting with an ambient temperature and thermophilic composting are two methods for converting livestock manure into fertilizer. This study investigated the variations in ARGs and mobile genetic elements (MGEs) and revealed potential mechanisms for ARGs removal using the two composting methods. The ARGs abundance were enriched by 44-fold in heap composting, among them, the macrolide-resistance genes increased significantly. On the contrary, the ARGs were removed by 92% in thermophilic composting, among them, tetracycline-resistance genes decreased by 97%. The bacterial hosts of ARGs were associated with the variations of ARGs and MGEs. The tetO was correlated with the most diverse bacteria in heap composting, and Bacteroidetes was the major host bacteria. While tetT was correlated with the most diverse bacteria in thermophilic composting, and Proteobacteria was the major host bacteria. Structural equation models showed that the enrichment of ARGs in heap composting was mainly correlated with bacterial communities, whereas, the removal of ARGs in thermophilic composting was directly affect by MGEs. Composting temperature directly affected the variations in ARGs. Higher and lower temperatures significantly decreased and increased, respectively, ARGs and MGEs abundance levels.

https://www.sciencedirect.com/science/article/abs/pii/S0269749122003888