碳青霉烯耐药肺炎克雷伯菌耐药机制及分子流行病学研究

Analysis of Carbapenem-resistant Klebsiella pneumoniae molecular epidemiology and antibiotic resistance gene

目的探讨临床分离的耐碳青霉烯肺炎克雷伯菌的耐药基因及分子流行病学研究。方法收集并鉴定临床分离非重复碳青霉烯耐药肺炎克雷伯菌株44株。采用Vitek 2compact全自动微生物鉴定药敏分析仪鉴定进行常规药敏试验,改良Hodge试验检测KPC型碳青霉烯酶,EDTA协同法检测金属β-内酰胺酶,聚合酶链反应(PCR)法检测细菌携带的耐药基因。肠杆菌基因间重复性共有序列ERIC-PCR对菌株进行同源性分析,了解其分子流行病学特征。结果44株肺炎克雷伯菌对碳青霉烯类、青霉素类、头孢菌素类和氨曲南等抗菌药物显示了较高的耐药性。改良Hodge试验阳性41株,金属酶检测试验结果均为阴性。PCR结果显示,临床分离的耐碳青霉烯肺炎克雷伯菌以KPC-2型为主,共42株。ERIC-PCR将44株肺炎克雷伯菌分为14型,以Ⅰ型为主,共18株,集中于重症监护室(ICU)和神经外科。结论分离的碳青霉烯耐药肺炎克雷伯菌对临床常用抗菌药物表现出高水平耐药;其耐药机制主要是该类细菌产KPC-2碳青霉烯酶,ICU与其它科室的患者频繁转诊治疗可能是导致碳青霉烯耐药肺炎克雷伯菌在全院范围播散流行的主要原因。

Objective To investigate the molecular epidemiology characteristics and drug resistance genes of imi-penem-resistant Klebsiella pneumoniae isolated. Methods A total of 44 strains of Carbapenem- resistant Klebsiella pneumoniae were collected and identified. Conventional drug susceptibility test was made by Vitek 2 compact automatic microbe susceptibility analyzer appraisal. Susceptibility testing for antibiotics was performed by the disc diffusion method carbapenemase production was confirmed by modified Hodge test and MBL production by IPM / IPMEDTA combined disc test. The resistant genes were detected by PCR. Molecular epidemiology characteristics were analyzed by enterobacterial repetitive intergenic consensus sequence（ ERIC）-polymerase chain reaction（ PCR）. Results A total of 44 strains of bacteria showed a high level resistance to routine antibiotics including carbapenems,penicillins,cephalosporin and aztreonam. A total of 41 strains were positive in modified Hodge test and all the 44 strains were negative to enzyme detection test. PCR result showed that 42 strains were of KPC-2 type,none of other gene types. ERIC-PCR result showed that 44 strains of Klebsiella pneumoniae were divided into 14 types,and the main type was type I. 18 strains belonged to type I from ICU and neurosurgery. Conclusion Klebsiella pneumoniae that resists to carbapenem shows high levels of resistance to routine antibiotic in our hospital. Strains of carbapenem resistant Klebsiella pneumoniae appear,KPC-2 is the main reason to cause the bacterial resistance to carbapenems.Frequent transfer treatment of the patients among ICU and other clinical departments is the primary factor of carbapenem-resistant Klebsiella pneumonia epidemic in the entire hospital.