碳青霉烯类耐药肠杆菌科细菌多黏菌素耐药性调查及分子机制分析  

Survey and molecular mechanisms of polymyxin-resistance in carbapenem-resistant Enterobacteriaceae

作　　者：张雪 谢小芳[1] 王敏[1] 郑毅[1] 杜鸿[1] ZHANG Xue;XIE Xiaofang;WANG Min;ZHENG Yi;DU Hong(Clinical Laboratory Department,the Second Affiliated Hospital of Soochow University,Suzhou 215004,Jiangsu,China)

机构地区：[1]苏州大学附属第二医院检验科,江苏苏州215004

出　　处：《临床检验杂志》2020年第8期592-596,602,共6页Chinese Journal of Clinical Laboratory Science

基　　金：江苏省科技厅重点研发计划(BE2017654);苏州市临床微生物学重点实验室项目(SZS201715);苏州市科技计划民生科技项目(SYS201619,SLT201934)。

摘　　要：目的了解在我国临床正式应用多黏菌素前碳青霉烯类耐药肠杆菌科细菌(carbapenem-resistant Enterobacteriacea,CRE)多黏菌素的耐药现状和耐药机制。方法收集2017年1月至12月苏州、成都、北京3个地区临床分离的非重复CRE菌株,用微量肉汤稀释法和Phoenix 100自动微生物系统进行药敏分析。对多黏菌素耐药菌株,用PCR扩增和Sanger测序检测mcr-1~mcr-9以及多黏菌素耐药调控基因突变,用实时荧光定量PCR检测多黏菌素耐药调控基因表达量变化。结果共收集341株CRE菌株,检测出11株(占3.2%) CRE对多黏菌素耐药,包括8株肺炎克雷伯菌、2株大肠埃希菌和1株阴沟肠杆菌。1株肺炎克雷伯菌检出mgr B插入序列,2株大肠埃希菌检出mcr-1基因,1株阴沟肠杆菌检出mcr-9基因。荧光定量PCR结果显示,在多黏菌素耐药菌株中pmr A、pmr C、pmr K和pho Q基因表达显著上调。结论即使没有使用多黏菌素治疗,也有部分CRE菌株对多黏菌素耐药,主要是染色体和质粒编码的耐药机制。提示临床应加强细菌耐药监测和抗菌药物管理,避免多黏菌素耐药性的进一步传播。Objective To investigate the epidemic status and resistance mechanism of polymyxin for carbapenem-resistant Enterobacteriaceae( CRE) before the formal clinical application in China. Methods The non-repetitive clinical isolates of CRE were collected in Suzhou,Chengdu and Beijing regions from January to December 2017. The drug sensitivities were analyzed by broth microdilution method and Phoenix 100 automated microbiology system. For the polymyxin-resistant strains,the drug-resistant genes mcr-1 to-9 and the mutations of resistance-regulatory genes were detected by PCR amplification and Sanger sequencing. The variation of expression of polymyxin resistance regulatory genes was detected by real-time fluorescent quantitative PCR. Results A total of 341 strains of CRE were collected,of which 11 stains( 3.2%) were resistant to polymyxin,including 8 Klebsiella pneumoniae,2 Escherichia coli and 1 Enterobacter cloacae. The insertion sequence mgr B was detectable in a strain of K. pneumoniae,the mcr-1 gene was detectable in 2 strains of E. coli,and mcr-9 gene was detectable in a strain of E. cloacae. Real-time fluorescent quantitative PCR analysis showed that the expressions of pmr A,pmr C,pmr K and pho Q genes were significantly up-regulated in polymyxin resistant strains. Conclusion Even if polymyxin did not adopted in treatment,some CRE strains were found to be resistant to polymyxin which may be mainly due to the resistance mechanism encoded by chromosomes and plasmids. The results in this study suggested that the monitoring for bacterial resistance and the management of antibacterial drug should be paid special attention in clinical practice to avoid the further spread of polymyxin resistance.

关 键 词：碳青霉烯类耐药肠杆菌科细菌 多黏菌素 耐药机制 

分 类 号：R446.5[医药卫生—诊断学]