3株耐碳青霉烯鲍曼不动杆菌临床株耐药机制的研究

The mechanism of three carbapenem-resistant clinical isolates of Acinetobacter baumannii

目的研究鲍曼不动杆菌(Acinetobacter baumannii)对碳青霉烯耐药的分子机制。方法采用琼脂纸片扩散法(KB法)及微量肉汤法筛选出3株对碳青霉烯耐药的鲍曼不动杆菌临床株,PCR扩增blaOXA-23基因和测序、提取外膜蛋白及进行聚丙烯酰胺凝胶电泳(SDS-PAGE)。结果3株耐碳青霉烯的鲍曼不动杆菌具有多重耐药性;耐药基因PCR扩增和测序证实3株耐药菌均有blaOXA-23基因;其中1株耐药菌AB173的外膜蛋白电泳条带在28.8ku处出现明显缺失,其余2株耐药菌在该条带处与敏感菌相比较无明显差异。结论本次试验中对碳青霉烯耐药的鲍曼不动杆菌全部含有blaOXA-23基因,其中一株耐药菌还出现了外膜蛋白孔道的缺失可能与其多重耐药性有关。

Objective To study the molecular mechanism of carbapenem-resistant Acinetobacter baumannnii. Methods The carbapenem-resistant strains were detected from clinical isolatesAcinetobacter baumannii by disk diffusion and micro-diluted broth method. The b/aoxA-23 gene was amplified by PCR method and then sequenced. Their out membrane proteins （OMP） were extracted and analyzed by using SDS-polyacry- lamide gel electrophoresis and a carbapenem-susceptible Acinetobacter baumannnii strain as control. Results The PCR amplification and sequencing results showed that the three multi-resiltant Acinetobacter baurnannii isolates were multi-resistant and all carried blaoxA-23 gene. The SDS-PAGE electrophoresis result showed that 28. 8ku-band deficiency was found in A. baurnannii AB173, whereas other two resistant isolates showed the same electrophoresis profiles with the control. Conclusions In this experiment, all three carbapenem-resistant Acinetobacter baumannii strains carried blaoxA-23 gene and one of them lacked a 28.8ku OMP, which were probably attributed to the multi-resistance of organisms.