环境中重金属暴露对抗生素抗性基因演变影响研究进展

Research progress on the effect of heavy metal exposure on the evolution of antibiotic resistance genes in the environment

抗生素抗性基因(ARGs)已被列为环境新兴污染物,其污染散播和环境演变已成为生态环境领域的关注焦点和研究热点。重金属因其不可降解性,可在自然环境中稳定存在,具有长期生物可利用度,对ARGs会产生持续性选择性压力影响。综述了细菌在抗生素、重金属,以及二者协同作用条件下的不同抗性机制,重点探讨了重金属对ARGs存在丰度和水平转移等环境行为的过程影响。结果表明:多种重金属及其化合物会对ARGs的丰度和水平转移产生影响,根据重金属的种类以及浓度不同可能会产生不同的影响结果;重金属影响ARGs水平转移主要是通过影响细胞分泌胞外聚合物(EPS)、改变细胞膜通透性以及影响基因表达等方式,不同种类的重金属可通过不同的方式影响ARGs的水平转移。虽然目前关于重金属对ARGs环境行为的过程影响已有较多研究报道,但是针对重金属对ARGs影响的内在机制以及不同环境介质中重金属对ARGs丰度和水平转移的协同选择作用有待进一步的研究。

Antibiotic resistance genes(ARGs)have been listed as an emerging contaminant in the environment.Their pollution dissemination and environmental evolution have become the attentive focuses and research hotspots in the field of ecological environment.Due to their non-degradability,heavy metals can stably exist in the environment and have long-term bioavailability,posing a continuous selection pressure on ARGs.The different resistant mechanisms of bacteria to antibiotics and heavy metals,as well as their synergistic effects were summarized.The influence of heavy metals on the environmental behaviors including gene abundance and horizontal transfer of ARGs was emphatically discussed.The results showed that a variety of heavy metals and their compounds would affect the abundance and horizontal transfer of ARGs.Different types and concentrations of heavy metals may have different effects.Heavy metals affected the horizontal transfer of ARGs mainly by affecting the secretion of EPS,changing the cells permeability,and affecting genes’expression,etc.Different types of heavy metals could affect the horizontal transfer of ARGs in different ways.Although there had been many research reports on the impact of heavy metals on the environmental behavior process of ARGs,the internal mechanism of the influence of heavy metals on ARGs and the synergistic selection effect of heavy metals on the abundance and horizontal transfer of ARGs in different environmental media need to be further studied.