2017-2020年某院临床分离耐碳青霉烯阴沟肠杆菌检测及分析

Hospital laboratory study of carbapenem-resistant Enterobacter cloacae from 2017 to 2020

目的通过研究本院近3年耐碳青霉烯阴沟肠杆菌,探讨其临床分布及相关耐药基因分布情况。方法收集2017年1月至2020年9月山西白求恩医院分离的33株耐碳青霉烯阴沟肠杆菌为研究对象,利用全自动快速生物质谱检测系统(美国Bruker,MicroflexLT/SH)进行细菌鉴定,VITEK2-Compact全自动微生物分析系统进行细菌药敏试验。采用改良碳青霉烯灭活试验进行耐药表型筛选。采用PCR方法检测碳青霉烯酶基因(bla_(IMP)、bla_(KPC)、bla_(NDM)、bla_(VIM)和bla_(OXA-48))。对所有菌株进行MLST分型和同源性分析。质粒接合转移实验研究耐药质粒的传播。结果22株阴沟肠杆菌对厄他培南、亚胺培南、美罗培南均耐药,11株仅对厄他培南耐药。其中16株阴沟肠杆菌产_(NDM)-1,4株产_(NDM)-5,2株产IPM-1,1株菌同时产_(NDM)-1和_(KPC)-2。11株仅对厄他培南耐药阴沟肠杆菌中有两株检出bla_(NDM)-1、两株检出bla_(KPC)-2基因。MLST分型主要流行株为ST418型。质粒接合转移实验有14株转移成功。结论本院耐碳青霉烯类阴沟肠杆菌从2017年逐年增加,2020年出现暴发流行。携带的碳青霉烯酶基因以bla_(NDM)为主,ST418型菌株占多数。耐药基因可通过质粒水平传播,所以加强临床耐药菌株筛检及控制对临床抗感染治疗作用关键。

Objective To investigate the clinical distribution and drug resistance gene distribution of carbapenem resistant Enterobacter cloacae in our hospital in recent three years.Methods 33 strains of carbapenem resistant Enterobacter cloacae isolated from Shanxi Bethune hospital from January 2017 to September 2020 were selected as the research objects.The bacteria were identified by MALDI-TOF(Bruker,microflexlt/SH),and the bacterial susceptibility test was carried out by automatic microbial analysis system compact vitek2.Modified carbapenem inactivation test was used to screen resistant phenotypes.Carbapenemase genes(bla_(IMP),bla_(KPC),bla_(NDM),bla_(VIM),and bla_(OXA-48))were detected by PCR.MLST typing and homology analysis were performed on all strains.Plasmid conjugation transfer assay was used to study the transmission of drug-resistant plasmids.Results 22 strains of Enterobacter cloacae were resistant to ertapenem,imipenem and meropenem,and 11 strains were only resistant to ertapenem.Among them,16 strains produced _(NDM)-1,4 strains produced _(NDM)-5,2 strains produced IPM-1 and 1 strain produced both _(NDM)-1 and _(KPC)-2.bla_(NDM)-1 and bla_(KPC)-2 genes were detected in two of 11 strains of Enterobacter cloacae resistant to ertapenem.The main epidemic strain of MLST was ST418.14 strains were successfully transferred by plasmid conjugation.Conclusion The number of carbapenem resistant Enterobacter cloacae in our hospital increased since 2017,and an outbreak in 2020.Main carbapenemase gene is bla_(NDM),and ST418.Drug resistant genes can be transmitted in plasmid level,so that strengthening the screening and control of clinical drug-resistant strains is the key to clinical infection treatment.