环境中噬菌体携带耐药基因传播的研究进展

Research advances of bacteriophages in contributing antimicrobial resistance gene in the environment

噬菌体是地球上最丰富和最多样化的生物实体,其数量是细菌的10~100倍。它们感染易感细菌宿主,并通过转导作用在宿主细胞内繁殖或以前噬菌体形式整合自身基因至细菌基因组中,从而有助于它们在细菌宿主中的繁殖(短期)或进化(长期)。利用荧光定量PCR方法(q PCR)对不同环境来源的噬菌体基因进行定量分析,发现其基因组中携带大量的耐药基因(ARG),其中检出率及丰度最高的为耐β-内酰胺抗生素的基因,主要为blaTEM、blaCTX-M-groups、blaSHV、blaNDM和blaKPC,以及耐氟喹诺酮类药物的基因qnr A、qnr B和qnr S。且随着高通量测序方法的不断改进,用此方法针对不同样品的宏基因组测序结果分析也同样发现了高水平ARG的存在。这些结果表明噬菌体可能成为潜在的储存载体,促进抗生素耐药性的传播。本文将从荧光定量PCR(q PCR)方法和全基因组测序方法两方面综述全球不同环境样本中噬菌体基因组携带ARG的情况以及其多样性和丰度的研究进展,并讨论其潜在危害性,希望引起更多的关注。

Bacteriophages(or phages)are the most abundant and diverse biological entities on earth,and the number is 10-100 times higher than that of bacteria.They infect susceptible bacterial hosts by transduction,enter the cells to reproduce or integrate their genes into the bacterial genome in the form of prophage,contributing to their preservation(short-term)or evolution(long-term).In recent years,it had been found that a large number of antimicrobial resistant genes(ARG)in phage genomes were detected and confirmed by quantitative PCR(qPCR)method from different environmental sources.Among these genes,β-lactamases resistance genes(bla TEM,bla CTX-M-groups,bla SHV,bla NDM and bla KPC)and fluoroquinolones resistant genes(qnrA,qnrB and qnrS)had the highest detection rate and absolute abundance.Nowadays,with the continuous progress of high-throughput sequencing methods(metagenomic analysis),the results of metagenomic analysis on different environmental samples also revealed the presence of high levels of ARG.These results suggest that bacteriophage may be a potential vector and important reservoir to enhance the spread of antibiotic resistance.In this study,we will review the diversity and abundary of phage-carrying ARG in different global enviromental samples by qPCR methods and whole genome sequencing methods,and hope to assess their potential hazards and arouse more attention.