【摘要】 目的研究1株亚胺培南耐药肺炎克雷伯菌的耐药机理。方法采用浓度梯度法(Etest)测定细菌对各抗菌药物最低抑菌浓度(MIC)。通过等电点分析(IEF)、质粒抽提、接合试验、转化试验、聚合酶链反应(PCR)扩增及耐药基因克隆测序分析细菌编码的β内酰胺酶。结果临床分离的肺炎克雷伯菌等电点显示3条β内酰胺酶条带,分别为5.4、6.7和8.2。PCR 扩增测序临床分离菌含 TEM-1(pI,5.4)、SHV-12(pI,8.2)和 KPC-2(pI,6.7)β内酰胺酶编码基因。转化菌只有一条β内酰胺酶条带,为6.7。从转化菌质粒(60000bp)上获得1500bp 的克隆片段,测序证实其为KPC-2编码基因。结论亚胺培南耐药肺炎克雷伯菌的质粒上携带水解碳青霉烯类抗生素的 A 类2f组 KPC-2酶的编码基因。更多还原

【Abstract】 Objective To investigate the resistant mechanism of imipenem-resistant K. pneumoniae.Methods The minimal inhibitive concentrations (MICs) of the antimicrobial agents were determined by Etest.Isoelectric focusing electrophoresis (IEF),plasmid extraction,conjugation, transformation,PCR amplification,cloning and sequencing were carried out for analyzing the encoding gene of β-1actamases.Results Three kinds of β-1actamases were detected with pIs of 7.2,6.7,and 5.4.in a clinical strain of K.pneumoniae.These β-1actamases were TEM-I (pI,5.4),SHV-12 (pI,8.2) and KPC-2 ( pI,6.7 ) confirmed by sequencing of the PCR products.Only one band of β-1actamase with pI 6.7 was displayed in the transformant.A 1500 bp segment,which contained the KPC-2 gene confirmed by nucleotide sequence analysis,was cloned from a 60 000 bp plasmid of the transformant.Conclusion The strain of K.pneumoniae resistant to imipenem produces a plasmid-mediated carbapenemase KPC-2 which belongs to Bush group 2f,class A β-1actamase.更多还原