耐碳青霉烯类肺炎克雷伯菌耐药基因与可移动遗传元件的分析

Analysis of carbapenemase genes and mobile genetic elements in carbapenem resistant Klebsiella pneumoniae

目的分析耐碳青霉烯类肺炎克雷伯菌(carbapenem resistant Klebsiella pneumoniae,CRKP)中携带耐药基因类型与可移动遗传元件状况。方法收集2016—2019年26株临床分离CRKP,通过PCR扩增与序列分析,确定其多位点序列分型(multilocus sequence typing,MLST)与碳青霉烯耐药基因类型,分析相关整合子、转座子、插入序列与接合质粒遗传标记基因等可移动遗传元件。结果收集的26株CRKP共有4种ST型,21株为ST11型,ST571型3株,ST23型和ST37型各1株。25株CRKP携带bla_(KPC-2)基因,同时还检出bla_(OXA-48)、bla_(NDM-1)、bla_(IMP-4)与bla_(VIM)耐药基因,其中6株携带多种耐药基因。共检测到7种可移动遗传元件序列,包括IS Ecp1、merA、tnp A、tnp 513、IntI 1、traA与trbC。结论ST11型为主要流行基因型,bla_(KPC-2)基因为CRKP主要耐药基因,同时存在携带多种耐药基因(bla_(KPC-2)、bla_(OXA-48)、bla_(NDM-1)、bla_(IMP))的菌株,国内少见报道。CRKP检出多种可移动遗传元件(merA、tnpA、tnp 513、IntI 1、traA与trbC),耐药基因的水平转移主要以插入序列、整合子、转座子介导。

Objective The carbapenemase gene types and mobile genetic elements in carbapenem resistant Klebsiella pneumoniae(CRKP) were analyzed and confirmed in this research. Methods 26 clinical isolates of CRKP were collected from 2016 to 2019. The bacterial type determined by multilocus sequence typing(MLST) and carbapenemase genes were simultaneously determined by PCR and sequence analysis. The mobile genetic elements(MGE) such as integron, transposon, insertion sequence or conjugation plasmid genetic marker genes were analyzed by genetic determination as well. Results Among the 26 CRKP strains collected in this study there were 5 ST types detected, 21 strains were ST11, 3 strains would be ST571, the rest 2 isolates shared the ST23 or ST37 respectively. While bla_(KPC-2) gene carried in 25 CRKP strains, also bla_(OXA-48)、bla_(NDM-1)、bla_(IMP-4)and bla_(VIM)resistance genes were also detected in these 26 CRKP strains. It is found multiple-drug resistance genes carried by 6 strains of research ones. There were seven kind of mobile genetic element sequences detected in the strains, which determined as IS Ecp1, merA, tnpA, tnp 513, IntI 1, traA or trbC. Conclusion ST11 was determined as the main prevalent genotype and bla;gene was the main resistance gene of CRKP in this study. Some strains detected for carrying multiple-drug resistance genes(such as bla_(KPC-2)、bla_(OXA-48)、bla_(NDM-1) or bla_(IMP)), which rarely reported in Chinese research. Then a variety of mobile genetic elements(such as merA, tnpA, tnp 513, IntI 1, traA or trbC) detected in these CRKP. Also the horizontal transfer of drug-resistant genes was mainly mediated by insertion sequence, integron or transposon.