多粘菌素耐药基因mcr-1的研究进展

ADVANCES IN RESEARCH ON POLYMYXIN RESISTANCE MECHANISM MCR-1

多粘菌素耐药基因mcr-1由1626个核苷酸序列组成,其主要作用是介导肠杆菌科细菌对多粘菌素产生抗药性。mcr-1基因可携带完整的ISApl1或ISApl1片段,翻译一段由541个氨基酸组成具有介导磷酸乙醇胺转移作用的酶。mcr-1能整合于质粒,可以随质粒在不同细菌中水平传播,甚至可以与其他的耐药基因共同存在于同一质粒,表达后产生多种耐药机制。mcr-1基因介导多粘菌素类药物耐药,但并不耐受目前所有的抗生素。本文对mcr-1基因的发现、分布、流行及耐药性等研究进展进行综述,以期为人类共同遏制多粘菌素类药物耐药基因的流行,及抗生素的安全用药提供可参考依据。

The mcr-1 gene was first discovered by Chinese scientists and its main role is to mediate polymyxin resistance in Enterobacteriaceae.mcr-1 is 1626-basepair in size and the content of guanine and cytosine accounts for about half.According to previous study,mcr-1 translates an enzyme that mediates the transfer of phosphoethanolamine and consists of 541 amino acids.The host bacteria of mcr-1 can harbor the intact or truncated ISApl1 element.mcr-1 is a plasmid-carrying gene but not a new bacterial variant.It only mediates polymyxin resistance,but not to all current antibiotics.The mcr-1 can be integrated into plasmid,which mediates its horizontal transfer in different bacteria.It can even coexist with other drug resistance genes in a single plasmid,and a variety of drug resistance phenotypes are generated after expression.The mcr-1 is frequently found in Escherichia coli,which is widely found in nature.The toxicity of polymyxin is mainly directed to the kidney,which is caused by the increase of blood urea nitrogen and creatinine levels caused by acute renal failure,resulting in the appearance of somatic cells and proteins in the urine.To prevent the impact of mcr-1 on humans,we should fi rst reduce the proliferation and infection of mcr-1-carrying bacteria in human.Governments at all levels and related public health surveillance should carefully monitor and report the use of antibiotics in their jurisdictions.Effective management of further spread of the gene in human and animal can be achieved by inhibiting the development of colistin resistance.We should be well prepared to deal with the problem of drug resistance.