鲍曼不动杆菌耐药性与生物被膜及外膜蛋白基因ompA相关性研究

Correlation of Acinetobacter baumannii resistance to Biofilms and to the outer membrance protein gene ompA

目的对鲍曼不动杆菌耐药性与生物被膜及外膜蛋白基因ompA的相关性进行研究。方法收集非重复鲍曼不动杆菌126株，采用琼脂扩散（K—B）法进行体外药敏实验；改良平板法测定生物被膜形成能力；采用聚合酶链反应（PCR）法扩增外膜蛋白基因ompA；采用反转录聚合酶链反应（RT—PCR）半定量法测定生物被膜形成的不同阶段外膜蛋白基因ompA表达水平的变化。结果126株鲍曼不动杆菌中，多重耐药菌分离率为62．70％（79／126）；PCR检测到多重耐药鲍曼不动杆菌中ompA基因的检出率为87．34％（69／79）；R-PCR检测到浮游菌、生物被膜3d、生物被膜5d外膜蛋白基因表达的相对灰度值分别为0．5573±0．3053、0．8208±0．0957、1．0975±0．2086，统计学分析显示，外膜蛋白基因ompA在生物被膜生长的不同时期其表达水平的差异有统计学意义。结论鲍曼不动杆菌耐药情况严峻，多重耐药菌分离率呈升高趋势；多重耐药性可能与生物被膜形成及外膜蛋白基因ompA高表达有关。

Objective To investigate the antimicrobial resistance of Acinetobacter baumannii,and to examine the correlation between antibiotic resistance and biofilm formation, and detect the expression level of the outer membrance protein gene ompA throughout the course of biofilm development. To study the correlation between biofilms and ompA. Methods 126 non-repeatability Acinetobacter baumannii strains were collected. The broth microdilution method applied to detect drug sensitivity of all strains. The modified flat-board method was used to establish Aeinetobacter baumannii biofilms model and observe the formation of bacterial biofilms. The crystal-violet straning metheod were selected to estimate the biofilm formation ability of A. baumannii. The outer membrance protein gene ompA were applied by polymerase chain reaction（PCR）. The ompA gene throughout different course of biofilm development were amplified by reverse transcription polymerase chain reaction（RT-PCR）, the expression of ompA were analyzed by semiquantitative analysis of gel eletropboresis. Results 79 non-repetitive multi-drug resistant Acinetobacter baumannii（MDRAb） were selected, account for 62.70%. By PCR technology, the positive rate of ompA gene in MDR was 87.34%. By RT PCR technology, the relative intensity of mRNA expression of ompA was 0.557 3±0.305 3,0.820 8±0.095 7,1. 097 5±0.208 6 in 20 of the biofilm positive and multiresistant strains. Statistical analysis showed the expression of the ompA was differernt throughout different course of biofilm development. Conclusions The separation rate of MDRAb is on the rise. The multi-drug resistance of Acinetobacter baumannii may correlated with biofilms and high expression of the outer membrance protein gene ompA.