耐碳青霉烯类肠杆菌科细菌的耐药基因及同源性分析

Alternative genes and homology analysis of carbapenem-resistant Enterobacteriaceae

目的对耐碳青霉烯类肠杆菌科细菌(CRE)进行耐药基因和同源性分析,了解其流行病学特征,为临床合理使用抗菌药物提供科学依据。方法对本院临床分离的60株CRE进行改良Hodge试验的表型鉴定,并对KPC、IMP、VIM、NDM与OXA-48五种常见的碳青霉烯酶基因进行检测;对17株产KPC酶的肺炎克雷伯菌(CRKP)进行肠杆菌基因间重复序列(ERIC)PCR分析。结果60株CRE菌株中,以肺炎克雷伯菌为主要致病菌,占88.33%(53/60)。产耐碳青霉烯酶基因有58株,其中KPC有50株(86.21%),NDM有9株(15.52%),IMP有2株(3.45%)。扩增出KPC和IMP的菌株有2株(3.45%),扩增出KPC和NDM的菌株有1株(1.72%),未扩增出OXA-48与VIM耐药基因。对ERIC-PCR结果进行聚类分析,结果可聚为三类,其中菌株8和17亲缘关系最近,相关系数最高达到了0.76,菌株14和16相关系数也达到了0.75,这两对菌株表现出较高的同源性。结论CRKP整体同源性不强,但某些菌株相关系数较高,CRE的多重耐药将给临床用药带来更大的挑战,应引起医院感染部门的高度重视。

Objective To investigate the resistance genes and homology of carbapenem-resistant Enterobacteriaceae to understand their epidemiological characteristics and provide scientific basis for rational clinical use of antibiotics.Methods The phenotype identification of the modified Hodge test was carried out on60 CRE strains isolated from our hospital,and the five common carbapenemase genes KPC,IMP,VIM,NDM and OXA-48 were tested.17 strains producing KPC enzyme Klebsiella pneumoniae(CRKP)was subjected to PCR analysis of Enterobacter intergenic repeat sequence(ERIC).Cluster analysis was applied to analyze their homology.Results Among the 60 CRE strains,Klebsiella pneumoniae was the main pathogen,accounting for 88.33%(53/60).There are 58 carbapenemase-resistant genes,of which 50 are KPC(86.21%),9 are NDM(15.52%),and 2 are IMP(3.45%).Two strains(3.45%)of KPC and IMP were amplified,and one strain(1.72%)of KPC and NDM were amplified.No OXA-48 and VIM resistance genes were amplified.The cluster analysis of ERIC-PCR results can be grouped into three categories.Among them,strain 8 and 17 have the closest genetic relationship,with the highest correlation coefficient reaching 0.76,and the correlation coefficient of strain 14 and 16 also reaching 0.75.Those two pairs of strains show high homology.Conclusion The overall homology of CRKP is not strong,but some strains have high correlation coefficients.The multidrug resistance of CRE will bring greater challenges to clinical medication,which should attract the attention of hospital infection departments.