临床分离耐亚胺培南革兰阴性菌的耐药性研究

Resistance of clinical isolates of imipenem-resistant gram-negative bacilli

目的研究临床分离耐亚胺培南(IMP)革兰阴性菌的耐药性。方法琼脂稀释法测定最低抑菌浓度(MIC),应用泵抑制剂检测外排泵,鉴定β-内酰胺酶(Bla)表型和测定等电点(pI),PCR扩增检测耐药基因。结果 121株IMP耐药革兰阴性菌对常用抗菌药物耐药率为56.5%～100.0%,102株产6种、3种和4种不同pI的超广谱β-内酰胺酶(ESBLs)、头孢菌素酶(AmpC)和金属β-内酰胺酶(MBL),92株PCR扩增检出blaTEM、blaSHV、blaCTX-M、blaKPC、blaPER、blaOXA-23、blaDHA、blaampC、blaMIR、blaIMP、blaVIM等基因,75株外排泵阳性,98株菌膜蛋白基因缺失,108株存在≥2种耐药机制。结论临床耐IMP革兰阴性菌存在多药耐药性和多种耐药机制,应注意检测和监控。

OBJECTIVE To study the resistant characteristics and the resistant mechanisms of the clinical isolates of imipenem-resistant gram-negative bacilli（G-） in the local nosocomial infections.METHODS The effects of efflux pump inhibitor on MICs were observed.Phenotypes and isoelectric points（pI） of β-lactamases（Bla） were determined.Bla Genes were amplified.RESULTS There was a high resistant rate（56.5%～100.0%） of all tested isolates（n=121） to the most antibiotics.Extended spectrum β-lactamases（ESBLs） with 6 different pIs,cephalospor in β-lactamase（AmpC） with 3 different pIs,and metallo-β-lactamase（MBL）with 4 different pIs,were detected in 102 strains.And 11 types β-Lactamase genes（blaTEM,blaSHV,blaCTX-M,blaKPC,blaPER,blaOXA-23,blaDHA,blaampC,blaMIR,blaIMP and blaVIM） were carried by 92 strains.Efflux pumps were observed in 75 strains,membrane protein genedeletion was found in 98 strains,and 108 strains were with more than 2 drug resistant mechanisms.CONCLUSION The clinical isolates of imipenem-resistant gram-negative bacilli present multiple drug resistance and a variety of mechanisms.We should focus on the detection and monitoring.