【摘要】 目的了解我院对碳青霉烯类抗生素敏感性下降的肺炎克雷伯菌的耐药机制及其同源性分析。方法收集2006年3月～9月我院对碳青霉烯类抗生素敏感性下降的肺炎克雷伯菌共10株,采用Etest法测定细菌对各抗菌药物的最低抑菌浓度(MIC);通过等电聚焦电泳(IEF)检测所产生的β-内酰胺酶,并通过聚合酶链反应(PCR)及序列分析确定其基因型;接合试验和Southern杂交进行基因定位;采用脉冲场凝胶电泳(PFGE)对这些菌株进行同源性分析。结果10株肺炎克雷伯菌均产KPC-2(pI6.7)、DHA-1(pI7.8)和SHV-28(pI7.6),其中3株同时产TEM-1广谱酶(pI5.4)。blaKPC-2位于60kb左右可接合性质粒上。10株菌株对β-内酰胺类抗生素呈多重耐药,但对多黏菌素,替加环素,复方SMZ敏感。PFGE证实为同一克隆株的传播。结论质粒介导的KPC-2造成肺炎克雷伯菌对碳青霉烯类抗生素敏感性下降,并在我院短暂流行;携带KPC-2基因的临床菌株同时携带多种耐药基因。更多还原

【Abstract】 Objective To investigate the mechanism of reduced susceptibility to carbapenems of Klebsiella pneumoniae and its homology. Methods Ten strains of Klebsiella pneumoniae with reduced susceptibility to carbapenems were collected in our hospital from March 2006 to Sep. 2006. The minimal inhibitive concentrations (MICs) of 10 isolates against the antimicrobial agents were determined by Etest.The encoding gene of β-lactamases was analyzed by isoelectric focusing electrophoresis (IEF),PCR amplification,cloning and sequencing, conjugation and southern blot.Homology was analyzed by pulsed field gel electrophoresis (PFGE). Results All of 10 strains produced KPC-2(pI 6.7), DHA-1(pI 7.8) and SHV-28(pI 7.6) β-1actamases. Three strains also produced TEM-1(pI 5.4). BlaKPC-2 was located in a 60kb plasmid. All strains were multi-resistant to β-lactam antibiotics, while susceptible to polymycin, tigecycline and SMZco. They had the same PFGE pattern. Conclusion Plasmid mediated KPC-2 caused low susceptibility to carpapenems in Klebsiella pneumoniae. The isolates with positive KPC-2 also carried other resistance genes.更多还原