产NDM-1阴沟肠杆菌的耐药性与毒力基因分布

Distribution of antimicrobial resistance and virulence genes of NDM-1-producing Enterobacter cloacae

目的了解产新德里金属β-内酰胺酶-1(NDM-1)阴沟肠杆菌(ECL)耐药性与毒力基因分布情况。方法收集2017年1月—2020年11月昆明医科大学第一附属医院分离的ECL,试验组为29株产NDM-1的耐碳青霉烯类ECL(CRECL),对照组为32株不产NDM-1的CRECL和35株碳青霉烯类敏感ECL(CSECL)。采用基质辅助激光解吸电离飞行时间质谱仪(MALDI-TOF MS)、全自动微生物分析系统进行菌株鉴定和药敏试验,PCR方法检测NDM-1耐药基因、24对毒力基因,采用χ^(2)检验比较毒力基因分布差异。结果该院分离的CRECL菌株NDM-1基因检出率为47.5%,产NDM-1的CRECL对常用抗菌药物表现为多重耐药。96株ECL菌株中,毒力基因acr A、tol C、wca A、wca M、wza的检出率较高,分别为80.2%、90.6%、87.5%、75.0%、92.7%,clp B、icmf、V as D/L ip基因的检出率也均在60%以上,未检出esc V、nle B、pet、hly A等毒力基因。产NDM-1的CRECL组clp B、icmf、V as D/L ip、acr A基因检出率高于不产NDM-1的CRECL,CRECL组clp B、icmf、V as D/L ip基因检出率高于CSECL组,差异具有统计学意义(P<0.05)。结论产NDM-1 CRECL耐药形势严峻而且毒力基因的携带率也增高,临床用药应兼顾细菌的耐药性和毒力基因分布情况。

Objective To understand antimicrobial resistance and distribution of virulence genes of New Delhi meta-llo-β-lactamase-1(NDM-1)-producing Enterobacter cloacae(ECL).Methods ECL isolated from the First Affiliated Hospital of Kunming Medical University from January 2017 to November 2020 were collected,the trial group was 29 strains of NDM-1-producing carbapenem-resistant ECL(CRECL),control group was 32 strains of CRECL without producing NDM-1 and 35 strains of carbapenem-sensitive ECL(CSECL).Strains were identified and performed antimicrobial susceptibility testing with matrix assisted laser desorption ionization time-of-flight mass spectrometer(MALDI-TOF MS)and automated microbial identification system,NDM-1 resistance genes and 24 pairs of virulence genes were detected by polymerase chain reaction,change in distribution of virulence genes was compared with Chi-square test.Results Isolation rate of NDM-1 gene of CRECL strain isolated in this hospital was 47.5%,NDM-1-producing CRECL showed multiple resistance to common antimicrobial agents.Among 96 ECL strains,detection rates of virulence genes acr A,tol C,wca A,wca M,and wza were 80.2%,90.6%,87.5%,75.0%and 92.7%respectively,detection rates of clp B,icmf,and V as D/L ip genes were also above 60%,virulence genes such as esc V,nle B,pet,and hly A were not found.Detection rates of clp B,icmf,V as D/L ip,and acr A genes in NDM-1-producing CRECL group were higher than those in CRECL group without producing NDM-1,detection rates of clp B,icmf,and V as D/L ip genes in CRECL group were higher than those in CSECL group,difference was statistically significant(P<0.05).Conclusion Antimicrobial resistance of NDM-1-producing CRECL is severe,and the carrying rate of virulence genes also increased,antimicrobial resistance and virulence gene distribution of bacteria should be considered in clinical medication.