摘要
目的研究儿科临床分离对碳青霉烯类抗生素不敏感的肠杆菌科细菌所产碳青霉烯酶的基因型。方法收集2008年1月至2010年12月北京儿童医院住院患儿中分离出的46株对碳青霉烯类抗生素不敏感的肠杆菌科细菌。使用改良Hodge试验和双纸片协同试验,进行产碳青霉烯酶的表型确证。PCR技术检测碳青霉烯酶的KPC、GES、IMI/NMC-A、SME、IMP、VIM、GIM、SPM、SIM、NDM-1和OXA基因型。对PCR反应产物进行纯化后,使用双脱氧末端终止法进行DNA测序。将得到的拼接序列,与GenBank中Blast进行同源分析,确定其基因亚型。结果 46株对碳青霉烯类抗生素不敏感的肠杆菌科细菌,26株为肺炎克雷伯菌,占56.5%,13株为阴沟肠杆菌,占28.3%,7株为大肠埃希菌,占15.2%。改良Hodge试验阳性40株(87.0%),双纸片协同试验阳性41株(89.1%)。IMP基因阳性38株(82.6%),其余8株均未扩增出特异性条带,检测均为阴性。测序结果显示,IMP型34株为IMP-4亚型,占89.5%;4株为IMP-8亚型,占10.5%。结论产金属酶是儿科临床分离对碳青霉烯类抗生素不敏感的肠杆菌科细菌的重要耐药机制。且产生的金属酶均为IMP基因型,同时存在IMP-4和IMP-8两种基因亚型,其中以IMP-4亚型为主,少数为IMP-8亚型。在儿科临床进行对碳青霉烯类抗生素不敏感的肠杆菌科细菌产碳青霉烯酶的监测十分重要。
Objective To explore the carbapenemase genotypes in carbapenem-nonsusceptible Enterobacteriaceae strains isolated from pediatric patients.Methods A total of 46 strains of carbapenem-nonsusceptible Enterobacteriaceae were isolated from the patients treated in Beijing Children′s Hospital between January2008 and December 2010.The phenotyes of carbapenemase producing strains were identified by Hodge test and double-disk synergy test.PCR was used to detect the genotypes of carbapenemase KPC,GES,IMI/NMC-A,SME,IMP,VIM,GIM,SPM,SIM,NDM-1 and OXA.The nucleotide sequences were compared with the sequences available over the Internet.Results Among the 46 carbapenem-nonsusceptible Enterobacteriaceae strains,26（56.5%）were Klebsiella pneumoniae,13（28.3%）Enterobacter cloacae and 7（15.2%）Escherichia coli.Forty（87.0%）strains showed positive Hodge test,41（89.1%）positive for double-disk synergy test,38（82.6%）positive for IMP genotype.The carbapenemase-related genes were not found in the remaining 8 strains.DNA sequencing revealed that IMP-4 was present in 34（89.5%）IMP-producing isolates.IMP-8 was detected in 4（10.5%）IMP-producing isolates.Conclusions Production of MBL is one of the important mechanisms of carbapenem-nonsusceptible Enterobacteriaceaein pediatric patients.Many carbapenem-nonsusceptible Enterobacteriaceae isolates carry blaIMP gene.Co-existence of IMP-4 and IMP-8 is identified.IMP-4-producing strains are the main prevalent strain in pediatric patients.It is very important to monitor the production of carbapenemases.
出处
《中国感染与化疗杂志》
CAS
北大核心
2013年第4期270-274,共5页
Chinese Journal of Infection and Chemotherapy
关键词
儿童
肠杆菌
碳青霉烯酶
基因
paediatrics
Enterobacteriaceae
carbapenemase
genotype
