摘要

       家畜粪便是抗生素抗性基因 (ARG) 的重要储存库。生物炭和沸石通常用于提高堆肥的质量，但是，关于这些添加剂对堆肥过程中 ARGs 命运的影响以及所涉及的潜在机制知之甚少。在这项研究中，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 ARG 模式的影响。堆肥后，对照中ARGs的丰度减少了92.6%，而ZL、BC、ZB的减少量分别为95.9%、98.7%和98.2%。共现网络分析表明，大多数 ARG 的潜在宿主主要隶属于厚壁菌门，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显示 intI1 基因对 ARGs 去除的贡献最大（标准化总效应为 0.92），这是由水平基因转移触发的。这些结果表明，沸石和生物炭的添加减轻了堆肥过程中 ARGs 的积累和扩散，水平基因转移 (HGT) 对 ARGs 行为的关键作用应在未来得到更多关注。

       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