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目的探索AdeABC主动外排系统及外膜蛋白在鲍氏不动杆菌对碳青霉烯类耐药中的作用。方法随机收集复旦大学附属中山医院临床标本鲍氏不动杆菌40株,以琼脂稀释法测定其对美罗培南、亚胺培南的最低抑菌浓度,按不同的耐药表型分组,进行羰基氢氯苯腙抑制试验,普通PCR扩增外排泵基因adeB,实时荧光定量PCR检测adeB基因表达水平;超声物理法提取外膜蛋白,12%十二烷基磺酸钠-聚丙烯酰胺凝胶电泳分析外膜蛋白。结果 40株鲍氏不动杆菌中,对亚胺培南、美罗培南均敏感检出15株,检出率37.5%,亚胺培南敏感美罗培南耐药检出6株,检出率15.0%,亚胺培南、美罗培南均耐药检出19株,检出率47.5%;中山医院鲍氏不动杆菌中,adeB外排泵基因广泛存在,在敏感菌株中存在率也很高;碳青霉烯类耐药组外排泵adeB基因的表达量相对高于敏感组,统计学分析3组之间差异无统计学意义;外膜蛋白分析发现,部分菌株有29 kd的条带丢失。结论主动外排系统和外膜蛋白缺失在鲍氏不动杆菌对碳青霉烯类耐药中可能发挥一定的作用。
Objective To explore the role of AdeABC active efflux system and outer membrane protein in the resistance of carbapenem to Acinetobacter baumannii. Methods Forty strains of Acinetobacter baumannii were randomly collected from Zhongshan Hospital Affiliated to Fudan University. The minimum inhibitory concentrations (MICs) of meropenem and imipenem were determined by agar dilution method. According to different resistance phenotypes, Chlorophenylhydrazone inhibition test, normal PCR amplification of efflux pump gene adeB, real-time fluorescence quantitative PCR adeB gene expression levels; ultrasonic physical extraction of outer membrane protein, 12% sodium dodecyl sulfate - polyacrylamide gel electrophoresis Analysis of outer membrane proteins. Results Among the 40 strains of Acinetobacter baumannii, 15 strains were sensitive to imipenem and meropenem, respectively, with a detection rate of 37.5% and 6 strains of imipenem - sensitive meropenem - resistant strains with a detection rate of 15.0% , 19 strains of imipenem and meropenem were all detected, and the detection rate was 47.5%. Among the Acinetobacter baumannii isolates in Zhongshan Hospital, adeB efflux pump gene was widely present in the susceptible strains, The expression level of adeB gene was higher in the penem resistance group than in the sensitive group. There was no significant difference among the three groups in the statistical analysis. The outer membrane protein analysis showed that some strains had a 29 kd band loss. Conclusion The deletion of active efflux system and outer membrane protein may play a role in the resistance of carbapenem to Acinetobacter baumannii.