摘要

      抗生素抗性基因 (ARG) 是新兴的环境污染物，对公众健康构成威胁。抗生素和金属被广泛用作饲料添加剂，因此可能会影响猪肠道中的 ARG。在这项研究中，使用多种统计方法分析了基于高通量定量聚合酶链反应 (HT-qPCR) 的 ARG 芯片和下一代 16S rRNA 基因扩增子测序数据，以分析抗生素抗性组并研究其与用作抗生素和金属的联系。中国三个大型养猪场新鲜采集的猪粪样品中的饲料添加剂和微生物群落组成。每克猪粪检测到总共 146 个 ARG 和高达 1.3 × 1010 的总 ARG 拷贝。赋予对氨基糖苷、大环内酯-林可酰胺-链霉菌素 B (MLSB) 和四环素抗性的 ARG 在猪肠道中占主导地位。 ARGs 的总丰度与饲料中抗生素、微生物生物量和移动遗传元件 (MGEs) 的丰度呈正相关（P < 0.05）。 Procrustes 分析观察到微生物群落和 ARG 谱之间的显着相关性。网络分析显示，拟杆菌门和厚壁菌门是与特定 ARG 共存的最主要门。部分冗余分析表明，ARG 谱的变化主要归因于饲料中的抗生素和金属（31.8%）、肠道微生物群落组成（23.3%）以及饲料添加剂与群落组成之间的相互作用（16.5%）。这些结果表明，饲料添加剂水平的增加可能会加剧猪肠道中 ARGs 和 MGEs 的富集。

       Antibiotic resistance genes (ARGs) are emerging environmental contaminants posing a threat to public health. Antibiotics and metals are widely used as feed additives and could consequently affect ARGs in swine gut. In this study, high-throughput quantitative polymerase chain reaction (HT-qPCR) based ARG chip and next-generation 16S rRNA gene amplicon sequencing data were analyzed using multiple statistical approaches to profile the antibiotic resistome and investigate its linkages to antibiotics and metals used as feed additives and to the microbial community composition in freshly collected swine manure samples from three large-scale Chinese pig farms. A total of 146 ARGs and up to 1.3 × 1010 total ARG copies per gram of swine feces were detected. ARGs conferring resistance to aminoglycoside, macrolide-lincosamide-streptogramin B (MLSB) and tetracycline were dominant in pig gut. Total abundance of ARGs was positively correlated with in-feed antibiotics, microbial biomass and abundance of mobile genetic elements (MGEs) (P < 0.05). A significant correlation between microbial communities and ARG profiles was observed by Procrustes analysis. Network analysis revealed that Bacteroidetes and Firmicutes were the most dominant phyla co-occurring with specific ARGs. Partial redundancy analysis indicated that the variance in ARG profiles could be primarily attributed to antibiotics and metals in feed (31.8%), gut microbial community composition (23.3%) and interaction between feed additives and community composition (16.5%). These results suggest that increased levels of in-feed additives could aggravate the enrichment of ARGs and MGEs in swine gut.

https://www.sciencedirect.com/science/article/abs/pii/S0048969717328115