源自同一患者的二株血和粪便对碳青霉烯类耐药大肠埃希菌  

Two carbapenem-resistant Escherichia coli strains isolated from blood and stool of a same patient

作　　者：王卫萍[1] 周志慧[2] 邵海枫[1] 魏泽庆[2] 俞云松[2] 

机构地区：[1]南京军区南京总医院临床中心实验科,210002 [2]浙江大学医学院附属第一医院感染科

出　　处：《中华传染病杂志》2010年第9期529-531,共3页Chinese Journal of Infectious Diseases

摘　　要：目的 了解对碳青霉烯类抗菌药物耐药大肠埃希菌的耐药机制及与内源性感染的关系.方法 将临床分离的来源于同一患者血培养和粪便培养的大肠埃希菌2株,采用浓度梯度法（E-test）测定亚胺培南、美罗培南的最低抑菌浓度（MIC）值,纸片扩散法测定其他16种抗菌药物的敏感性,等电聚焦电泳（IEF）检测所产生的β-内酰胺酶,PCR及序列分析确定其基因型,接合试验和Southern杂交进行耐药基因定位,脉冲场凝胶电泳（PFGE）分析2株菌株的同源性.结果 亚胺培南、美罗培南对2株大肠埃希菌的MIC值均≥32 mg/L,均产KPC-2（等电点值为6.7）和SHV-12（等电点值为8.2）.blaKPC-2基因位于可转移的54 kb质粒上.PFGE显示2株大肠埃希菌为同一克隆株.结论 2株大肠埃希菌的耐药性及染色体DNA酶切图谱均一致,该患者大肠埃希菌败血症极可能是肠道的大肠埃希菌移位引起的内源性感染.Objective To investigate the resistant mechanism of carbapenem-resistant Escherichia coli and its relationship with endogenous infection. Methods Two carbapenem-resistant Escherichia coli strains were isolated from blood and stool of a same patient, respectively. The minimal inhibition concentrations （MIC） of the two isolates against imipenem and meropenem were determined by E-test. The susceptibility against other antimicrobial agents were done by disc diffusion method. Isoelectric focusing electrophoresis （IEF）, polymerase chain reaction （PCR） amplification,cloning and sequencing, conjugation, Southern blotting were carried out to analyze the encoding gene of β-lactamases. Homology analysis of the two strains was done by pulsed field gel electrophoresis （PFGE）. Results MIC against imipenem and meropenem of the two strains were both≥32 mg/L.Both strains produced KPC-2 （pI 6.7） and SHV-12 （pI 8.2） β-lactamases. blaKPC2gene was located on a 54 kb transferable plasmid. PFGE showed that the two Escherichia coli strains were derived from the same clone. Conclusions The resistance and enzyme digestion map of chromosome DNA of the two Escherichia coli strains are coincident. The Escherichia coli septicemia of this patient is probably an endogenous infection caused by the immigration of Escherichia coli from the gut.

关 键 词：大肠杆菌 质粒 Β内酰胺酶类 感染 脓毒症 抗药性 微生物 

分 类 号：R686[医药卫生—骨科学]