【摘要】 以秀丽隐杆线虫为模式生物，结合定量PCR和平板筛选法证明抗性基因(ARGs)供体菌Escherichia coli MG1655和受体菌Salmonella typhimurium都能在肠道中稳定定殖。通过接合获得抗生素抗性的S.typhimurium数量与肠道总菌数的比值用以体现肠道中ARGs的扩散效率。在3 d的培养中，随着四环素浓度(0、0.08、0.4、2、10和50 mmol/L)的升高，ARGs扩散效率先升高后降低，其在0.4 mmol/L四环素处理组中达到峰值(第2和第3天分别为0.78%和1.96%)。并且，接合相关功能基因trfA/16S rRNA和trbB/16S rRNA的相对丰度与肠道组织中抗氧化酶活性显现出与ARGs扩散效应一致的趋势。研究表明，短暂且低浓度的抗生素可促进动物肠道内ARGs的扩散。更多还原

【Abstract】 Cryptobacterium hidradii used as a model organism, qPCR was combined with plate screening methods to demonstrate that the antibiotic-resistant genes(ARGs) donor bacterium Escherichia coli MG1655 and the acceptor bacterium Salmonella typhimurium were both able to colonize stably in the intestine. The ratio of the number of antibiotic-resistant S.typhimurium obtained via conjugation to the number of total intestinal bacteria was used to characterize the diffusion efficiency of ARGs in the intestine. The ARG diffusion efficiency increased and then decreased with increasing tetracycline concentrations(0, 0.08, 0.4, 2, 10, and 50 mmol/L) over three days of incubation, and it peaked at 0.78% and 1.96% on the second and third days in the 0.4 mmol/L tetracycline-treated group, respectively. Moreover, the relative abundance of conjugation-relevant functional genes trfA/16S rRNA and trbB/16S rRNA as well as activities of antioxidant enzyme in intestinal tissues shared similar trends with the ARG diffusion ratios in the gut of snails. Therefore, the present study demonstrated that a brief and low concentration of antibiotics could promote the diffusion of ARGs in the animal intestine.更多还原