摘要

通过抗生素、饮食改变和感染引起的肠道微生物群的生物失调可以选择更频繁携带抗生素抗性基因( ARGs )和移动遗传元件( MGEs )的细菌群。然而，环境毒物对肠道微生物中ARGs库的影响受到的关注较小。2，3，7，8 -四氯二苯并对二恶英( TCDD )是一种有效的芳香烃受体( AhR )激动剂，具有多种毒性，包括免疫功能障碍。采用C57BL / 6小鼠，在0～30μg / kg的TCDD作用28天和92天，后者有30天的恢复期，研究了TCDD对ARG和MGE肠道菌群丰度的选择性压力。从临时收集的粪便颗粒中提取的DNA使用qPCR阵列进行鉴定，其中384种试验针对ARGs和MGEs。一般在肠杆菌科观察到的14个基因在初始给药后8天内显著增加，在整个治疗期间持续存在，并在给药后30天保持诱导。针对肠杆菌科的qPCR引物组在TCDD处理的组中也显示出10 - 100倍的高丰度，这通过宏基因组学进一步证实。结果表明，由于非金属、杀生物剂或抗微生物剂的异生素化合物，肠道中含有大量ARG的细菌群。

Dysbiosis of the gut microbiome via antibiotics, changes in diet and infection can select for bacterial groups that more frequently harbor antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs). However, the impact of environmental toxicants on the reservoir of ARGs in the gut microbiome has received less attention. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent aryl hydrocarbon receptor (AhR) agonist with multiple toxic health effects including immune dysfunction. The selective pressure of TCDD on the abundance of ARG and MGE-harboring gut populations was examined using C57BL/6 mice exposed to 0–30 μg/kg TCDD for 28 and 92 days with the latter having a 30-day recovery period. DNA extracted from temporally collected fecal pellets was characterized using a qPCR array with 384 assays targeting ARGs and MGEs. Fourteen genes, typically observed in Enterobacteriaceae, increased significantly within 8 days of initial dosing, persisted throughout the treatment period, and remained induced 30 days post dosing. A qPCR primer set targeting Enterobacteriaceae also showed 10- to 100-fold higher abundance in TCDD-treated groups, which was further verified using metagenomics. Results show a bloom of ARG-harboring bacterial groups in the gut due to a xenobiotic compound that is not a metal, biocide or antimicrobial.

https://academic.oup.com/femsec/article-abstract/93/5/fix058/3798199