State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; National Engineering Laboratory for Industrial Wastewater Treatment, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Environ Int. 2019 Oct;131:105008. doi: 10.1016/j.envint.2019.105008. Epub 2019 Jul 20.
This study aimed to investigate the impact of tigecycline, the third generation tetracycline, on the antibiotic resistance development in environmental microbiota. Two biological contact oxidation reactors containing aerobic biofilm microbiota were constructed, one of which was constantly fed with synthetic wastewater spiked with increasing concentrations of tigecycline (0 to 25 mg/L) under a hydrolytic retention time of 24 h. Over a period of 636 days, chemical oxygen demand removal over 90% and complete nitrification were achieved for both the control and tigecycline-exposed reactors, and effluent tigecycline concentrations in the tigecycline-exposed system were always <0.051 mg/L. Significant increases (p < 0.01) in resistome abundance and resistant bacteria ratio were detected at a tigecycline dose of 10 and 25 mg/L, respectively, revealed by metagenomic sequencing and culture-based method. The increase of resistome in the tigecycline system was mainly attributed to the enrichment of tetX, one cooperative tetracycline degrading gene. Partial canonical correspondence analysis showed that the change of resistome was mainly driven by bacterial community shift (vertical pathway). Network and genome binning analyses further suggested that the proliferation of Flavobacterium harboring tetX contributed to a relatively low community-wide resistance development in the aerobic biofilm microbiota under tigecycline selection by reducing the antibiotic concentration. This work provides scientific bases for the management and evaluation of the resistance risk induced by this novel antibiotic.
本研究旨在探讨第三代四环素类药物替加环素对环境微生物群落抗生素耐药性发展的影响。构建了两个含有好氧生物膜微生物群落的生物接触氧化反应器，其中一个在水解停留时间为 24 小时的条件下，连续用含有不同浓度替加环素（0 至 25mg/L）的合成废水进行喂养。在 636 天的时间内，对于对照和替加环素暴露的反应器，均实现了化学需氧量去除率超过 90%和完全硝化，并且替加环素暴露系统的出水替加环素浓度始终<0.051mg/L。通过宏基因组测序和基于培养的方法检测到，在替加环素剂量为 10 和 25mg/L 时，耐药组的丰度和耐药菌比例分别显著增加（p<0.01）。替加环素系统中耐药组的增加主要归因于tetX 的富集，tetX 是一种协同的四环素降解基因。部分典范对应分析表明，耐药组的变化主要由细菌群落的变化（垂直途径）驱动。网络和基因组分箱分析进一步表明，在替加环素选择下，Flavobacterium 携带 tetX 的增殖通过降低抗生素浓度，有助于好氧生物膜微生物群落中相对较低的全社区耐药性发展。这项工作为管理和评估这种新型抗生素引起的耐药性风险提供了科学依据。
