摘要

      根据中国新的环境保护政策，在没有足够处理设施的情况下运作的养猪场正在被拆除。这些废弃猪场的环境行为和抗微生物基因（ARGs）的传播风险尚不清楚。对40份来自两个废弃和两个工作猪场附近土壤的土壤样品进行了研究：1）17个精氨酸和2个整合子基因的分布格局和垂直传播；2）细菌群落及其与环境因子和目标基因的相关性。我们发现48个亚型中，有7个和9个分别在废弃饲养场和工作饲养场附近的土壤中检测到。三个tet基因（tetM、tetO和tetW）在废弃和工作饲养场附近的土壤中特别丰富。tetM基因是表土网络上的“枢纽”。在北京两个饲养场附近土壤中，厚壁栎的相对丰度为2.5%～9%，显著高于上游空白对照（CK土壤）（方差分析，p<0.05）。总的来说，废弃猪场附近土壤中的ARG分布模式与工作猪场相似。本研究为猪场废弃饲料中精氨酸（ARGs）的流行及传播风险提供了基础资料，为废弃饲料的恢复利用提供参考。

      Swine feedlots that have operated in the absence of adequate disposal facilities are being demolished under the new environmental protection policies in China. The environmental behavior and transmission risks of antimicrobial resistance genes (ARGs) are unclear for these abandoned swine feedlots. We examined 40 soil samples that originated from the soils adjacent to two abandoned and two working swine feedlots to explore: 1) the distribution patterns and vertical transmission of 17 ARGs and two integron genes and 2) the bacterial community as well as their correlation with environmental factors and target genes. We found that seven and nine out of forty-eight subtypes of veterinary antimicrobials (VAs) were detected in the soil near abandoned feedlots and working feedlots, respectively. Three tet genes (tetM, tetO and tetW) were particularly enriched in the soil adjacent to both abandoned and working feedlots. The tetM gene was a "hub" on the network of the topsoil. The relative abundance of Firmicutes ranged from 2.5 to 9% in the soil near two Beijing feedlots and was significantly higher than that in the upstream blank control (CK soil) (ANOVA, p < 0.05). Overall, the ARG distribution patterns in the soils adjacent to abandoned swine feedlots were similar to the working feedlots. This study offers basic information on the prevalence and transmission risk of ARGs in abandoned swine feedlots and provides a reference for the restoration and reuse of demolished feedlots.

       https://www.sciencedirect.com/science/article/pii/S0269749119323942?via%3Dihub