鲍曼不动杆菌耐药性与相关外排泵机制的初步研究

Preliminary study on the resistance of Acinetobacter baumannii and mechanism of drug efflux pumps

目的研究鲍曼不动杆菌外排泵基因的分布与抗菌药物的关系。方法分别应用稀释法和纸片扩散法检测26株临床分离的多重耐药鲍曼不动杆菌对18种常用抗菌药物的最低抑菌浓度(MIC),PCR扩增adeB、adeJ、macB、emrB、abeS、abeM、craA外排泵基因,实时荧光定量RT-PCR检测外排泵基因的mRNA表达水平。结果26株多重耐药的鲍曼不动杆菌对18种抗菌药物耐药情况严重,其中3株为替加环素耐药菌株,所有菌株均对多粘菌素B敏感。临床分离的多重耐药的鲍曼不动杆菌株adeJ和abeM的检出率达到了100%(26/26),abes、adeB、craA的检出率分别为96.15%(25/26)、92.31%(24/26)、84.62%(22/26),外排泵基因macB、emrB检出率在80%以上。在转录水平上,替加环素耐药菌株的macB平均表达量水平是标准菌株的5.8倍。结论多重耐药的鲍曼不动杆菌外排泵基因macB、emrB、craA检出率较高,macB的相对表达量与替加环素耐药相关。

Objective To investigate the distribution of efflux pump gene and its relationship with drug resistance.Methods The minimal inhibitory concentration(MIC)of 18 antimicrobial agents against 26 multi-drug resistant Acinetobacter baumannii clinical isolates were determined by dilution method and disk diffusion method respectively.adeB,adeJ,macB,emrB,abeS,abeM,craA efflux pump genes were amplified by polymerase chain reaction(PCR).Quantitative gene real-time PCR was performed to investigate the expression of efflux pump genes.Results All twenty-six multi-drug resistant Acinetobacter baumannii showed highly resistant to 18 antimicrobial agents and three of them were tigecycline-resistant isolates.The detectable rate of clinically isolated multi-drug resistant Acinetobacter baumannii strains of adeJ and abeM were 100%(26/26),and the detection rates of abeS,adeB and craA were 96.15%(25/26)and 92.31%(24/26),84.62%(22/26),respectively.The detection rate of efflux pump gene macB and emrB was more than 80%.The average expression levels of macB of tigecycline-resistant strains was 5.8-fold than that of the standard strain.Conclunsion The detection rate of efflux pump gene macB,emrB,craA in multi-drug resistant Acinetobacter are higher,and the expression of macB is related to tigecycline resistance.