耐亚胺培南铜绿假单胞菌外膜孔蛋白与β-内酰胺酶研究  

Outer Membrane Protein and β-Lactamases in Imipenem Resistant Pseudomonas aeruginosa

作　　者：衣美英[1] 刘迎春[1] 王鹏远[2] 刘玉村[2] 

机构地区：[1]中日友好医院,北京100029 [2]北京大学第一医院,北京100034

出　　处：《中华医院感染学杂志》2007年第10期1198-1200,1203,共4页Chinese Journal of Nosocomiology

基　　金：国家高技术研究发展计划"863"重点基金资助项目(2002AA2Z341D)

摘　　要：目的探讨铜绿假单胞菌外科监护室分离株对碳青酶烯类抗菌药物耐药机制。方法琼脂稀释法测定抗菌药物最低抑菌浓度(MIC);提取β-内酰胺酶进行三维水解试验及等电聚焦电泳;紫外分光光度计测定酶活性;用PCR扩增IMP、VIM金属酶基因;用Western印迹分析外膜孔蛋白OprD2表达水平。结果从外科监护室分离的49株铜绿假单胞菌,有41株对亚胺培南耐药;耐药组34株菌产AmpC酶,其中8株同时产ESBLs酶,2株仅产ESBLs,未筛选出产金属酶菌株;亚胺培南耐药组酶活性(74.32±53.42)μmmol/mg与亚胺培南敏感组酶活性(8.7±16.16)μmmol/mg比较差异有统计学意义(P<0.01);耐药组OprD2表达均有不同程度的降低或缺失,而敏感组均正常表达OprD2,耐药组OprD2相对表达量(0.20±0.27)与敏感组(3.10±2.20)比较差异有统计学意义(P<0.01);未扩增出IMP、VIM金属酶基因。结论外膜孔蛋白OprD2表达降低或缺失以及高活性AmpC酶,是外科监护室耐亚胺培南铜绿假单胞菌的主要原因,与IMP、VIM金属酶关系不大。OBJECTIVE To investigate the mechanisms for carbapenem resistance in clinical isolates of Pseudomonas aeruglnosa from surgical intensive care unit（SICU）. METHODS The minimal inhibitory concentrations （MICs） of various antibiotics were detected with agar dilution method; their β-lactamases were extracted, types of their enzymes were identified and then their physical and chemical characteristics were studied by three dimentional extract test and isoelectric focusing （IEF） electropheresis;primers specific to IMP and VIM genes were utilized to amplify the metallo-β-lactamase genes. The levels of outer membrane protein OprD2 were measured by Western blot. RESULTS Forty one strains were resistant to imipenem from 49 strains of P, aeruginosa isolated from SICU during 3 years. Among them,34 isolates were found to produce high level of AmpC enzymes, Eight produced extended-spectrum β-lactamases （ESBLs） at the same time. 2 produced ESBLs only. No metallo-β-lactamases were detected. The activity of enzymes in the imipenem resistant group（74.32 ± 53, 42） was statistically different from the sensitive one（8.7 ± 16.16 ,P〈0. 01） ;all isolates in imipenem resistent group showed loss of OprD2 or a decreased OprD2 expression（23 showed loss of OprD2, and 18 had a decreased OprD2 expression）. All isolates sensitive to imipenem expressed normal OprDz. The expression level of OprD2 in the imipenem resistent group （0.20±0.27） was statistically different from the sensitive one（3.10±2.20,P〈0.01） ;neither IMP gene nor VIM gene was found in the isolates. CONCLUSIONS These results indicate that the imipenem resistance in clinical isolates from this SICU is mainly mediated by OprD2 deficiency or loss and high activity AmpC enzymes. IMP and VIM metallo-β-1actamases are rarely seen in this unit.

关 键 词：铜绿假单胞菌 亚胺培南 外膜孔蛋白 Β-内酰胺酶 

分 类 号：R378.991[医药卫生—病原生物学]