铜绿假单胞菌对亚胺培南耐药机制的研究

目的建立一种检测下呼吸道感染分离的铜绿假单胞菌对亚胺培南(IMP)耐药的筛选方法并研究其耐药机制。方法114株铜绿假单胞菌，用KB法筛选出亚胺培南耐菌株、可疑耐药株和敏感株；然后提取部分菌株外膜蛋白，进行SDS—PAGE电泳，比较三组菌株外膜蛋白的差异。结果114株铜绿假单胞菌中有13株耐药，37株可疑耐药(IMP抑菌圈内出现散在小菌落)3株中敏，61株敏感。在外膜蛋白SDS-PAGE电泳图谱上发现敏感株存在OprD2、OprE带，但耐药株、可疑耐药株缺乏OprD2；OprE带缺乏或者染色较淡。定量分析发现耐药株和可疑耐药株OprD2、OprE含量明显低于敏感株。结论KB法可以筛选出IMP可疑耐药的铜绿假单胞菌；IMP抑菌圈内出现散在菌落的菌株是耐药株；铜绿假单胞菌对IMP耐药的主要原因与外膜蛋白OprD2和OprE缺失或含量明显减少有关。

Study on imipenem resistance mechanism of Pseudomonas aeruginosa

Objective To establish a screening method to detect the resistance of Pseudomonas aeruginosa to imipenem and study imipenem resistance mechanism of Pseudomonas aeruginosa. Methods KB method was adopted to screen IMP-resistant strains, IMP-suspected-resistant strains and IMP-susceptible strains among 114 Pseudomonas aeruginosa. Then outer membrane proteins were extracted from some strains and were analyzed by SDS-PAGE. The differences of outer membrane proteins were compared in three groups. Results 13 strains were IMP-resistant, 37 strains were IMP-suspected-resistant (These strain scattered as small colonies in the agar plate), 3 strains were middle-susceptible, and 61 strains were IMP-susceptible. We found that there were OprD2 and OprE bands on SDS-PAGE profile of outer membrane proteins in IMP- susceptible-strains, but OprD2 were absent; and OprE were absent or the bands were light in IMP-resistant and suspected-resistant strains. By quantitative analysis the contents of OprD2 and OprE in IMP-resistant and suspected-resistant strains were lower than those in IMP-susceptible-strains. Conclusions KB test may be used to screen out those IMP-suspected-resistant strains of Pseudomonas aeruginosa. The scattered small colonies in the inhibitory zone of IMP were resistant strains. The main reason of IMP-resistant Pseudomonas aeruginosa might be due to the loss of outer membrane protein OprD2 and OprE, or the contents were decreased greatly.