摘要

       抗生素耐药基因（ARGs）是一种新兴的环境污染物，对公众健康构成威胁。抗生素和金属是广泛使用的饲料添加剂，因此可能影响猪肠道中的精氨酸。在这项研究中，以高通量定量聚合酶链反应（HT qPCR）为基础的ARG芯片和下一代16srrna基因扩增子测序数据，采用多种统计方法分析抗生素耐药性，并研究其与抗生素、饲料添加剂金属和微生物群落组成的关系从中国三个大型养猪场采集的新鲜猪粪样本中。每克猪粪中检测到146个精氨酸，总精氨酸拷贝数高达1.3×1010个。对氨基糖苷类、大环内酯类林可酰胺类、链霉素B（MLSB）和四环素耐药的ARGs在猪肠中占优势。精氨酸总丰度与饲料中抗生素、微生物生物量和移动遗传元素丰度呈正相关（P<0.05）。Procrustes分析表明，微生物群落与ARG剖面呈显著相关。网络分析表明，拟杆菌和厚壁菌是与特定ARGs共存的优势菌门。部分冗余分析表明，ARG谱的变异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%）和饲料添加剂与群落组成的相互作用（16.5%）。这些结果表明，饲料添加剂水平的增加会加剧猪肠道中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://linkinghub.elsevier.com/retrieve/pii/S0048-9697(17)32811-5