雷极普罗威登菌临床株对碳青霉烯酶类耐药的分子机制

Molecular mechanism of carbapenemase resistance in clinical isolate of Providence rettgeri

目的探讨雷极普罗威登菌临床株QD51对碳青霉烯酶类抗菌药物耐药的分子机制。方法采用梅里埃VITEK-2 Compact系统进行菌株的鉴定和药敏。聚合酶链式反应(PCR)扩增碳青霉烯酶耐药基因和产物测序确认基因型。质粒接合、S1-PFGE检测菌株的质粒。高通量测序平台获得接合子携带的质粒序列并用软件分析质粒的耐药基因。结果雷极普罗威登菌QD51临床株携带bla_(NDM-1)基因,且该菌能把携带的质粒转移到受体菌大肠埃希菌J53Azi^(R),获得接合子QD51C,命名该接合子携带的质粒为pNDM-QD51。S1-PFGE和高通量测序显示该质粒大小为134802 bp,属于IncA/C型,且含有blaNDM-1和bla_(CMY-6)基因。结论雷极普罗威登菌临床株QD51对碳青霉烯酶类耐药与其bla_(NDM-1)和bla_(CMY-6)基因有关,应引起临床重视。

Objective To discuss the molecular mechanism of carbapenemase resistance in clinical isolate of Providence rettgeri QD51.Methods Identification and antimicrobial susceptibility testing of the QD51 strain were performed by VITEK-2 Compact.The polymerase chain reaction(PCR)was used to amplify the carbapenemase resistance gene,product sequencing was used to confirm the genotype,and plasmid conjugation and S1-PFGE were used to detect the plasmid of the strain.The genes encoding cabapenemases were identified by polymerase chain reaction(PCR)and sequencing.Conjugation experiment and S1-PFGE were conducted to detect the transferability of plasmid.The sequence of plasmid in transconjugant was carried out using the Illumina MiSeq technology.The resistance genes in the plasmid were determinated by using softwares.Results PCR and sequencing indicated the blaNDM-1 gene in QD51 strain.The plasmid harboring blaNDM-1 was transferable to escherichia coli J53Azi^(R).The complete sequence of plasmid in transconjugant QD51C strain was obtained by using the WGS platform,and the plasmid was assigned as pNDM-QD51.Bioinformatics analysis verified that the pNDM-QD51,of 134802 bp in size,was a IncA/C plasmid carring bla_(NDM-1)and bla_(CMY-6).Conclusion The clinical isolate of Providencia rettgeri QD51 is related to carbapenemase resistance and blaNDM-1 and blaCMY-6 genes,and should be paid more attention to.