摘要

    牲畜粪便是抗生素抗性基因（ARG）的重要储存库。通常使用生物炭和沸石来提高堆肥的质量，但是，关于这些添加剂对堆肥过程中ARG的命运以及所涉及的潜在机制的影响知之甚少。在这项研究中，将沸石（ZL），生物炭（BC）或沸石和生物炭（ZB）同时添加到鸡粪堆肥中，以评估它们对ARGs模式的影响。堆肥后，对照组的ARGs含量降低了92.6％，而ZL，BC和ZB的降低幅度分别为95.9％，98.7％和98.2％。共现网络分析表明，大多数ARGs的潜在宿主主要隶属于Firmicutes，如乳酸杆菌和Fastidiosipila。此外，ARGs的变化与1类整合酶基因（intI1）显着相关，结构方程模型进一步揭示，intI1基因对ARGs的去除贡献最大（标准化总效应为0.92），这是由水平基因转移触发的。这些结果共同表明，添加沸石和生物炭可减轻堆肥过程中ARGs的积累和扩散，并且水平基因转移（HGT）在ARGs行为中的关键作用应在未来引起更多关注。

    Livestock manure is an important reservoir of antibiotic resistance genes (ARGs). Biochar and zeolite are commonly used to improve the quality of compost, however, little is known about the impacts of these additives on the fate of ARGs during composting and the underlying mechanisms involved. In this study, zeolite (ZL), biochar (BC), or zeolite and biochar (ZB) simultaneously were added to chicken manure compost to evaluate their effects on the ARGs patterns. After composting, the abundance of ARGs reduced by 92.6% in control, while the reductions were 95.9%, 98.7% and 98.2% for ZL, BC, ZB, respectively. Co-occurrence network analysis indicated that the potential hosts for most ARGs were predominantly affiliated to Firmicutes such as Lactobacillus and Fastidiosipila. Furthermore, shifts in ARGs were significantly correlated with class 1 integrase gene (intI1), and structural equation models further revealed that intI1 gene contributed most (standardized total effect 0.92) to the ARGs-removal, which was trigged by horizontal gene transfer. Together these results suggest that the addition of zeolite and biochar mitigate the accumulation and spread of ARGs during composting, and the crucial role of horizontal gene transfer (HGT) on the behaviors of ARGs should pay more attention to in the future.

    https://www.sciencedirect.com/science/article/abs/pii/S0304389420328740