多重耐药鲍曼不动杆菌耐药性分析及对替加环素敏感性降低的机制研究

Analysis of the resistance and the mechanism for decreased susceptibility to tigecycline for mulitidrug-resistant Acinetobacter baumannii

目的探讨多重耐药鲍曼不动杆菌对替加环素敏感性降低的机制。方法应用浓度梯度法检测多重耐药鲍曼不动杆菌对替加环素的敏感性,然后应用实时荧光定量PCR检测菌株中adeB外排泵基因的分布,最后应用实时荧光逆转录PCR技术测定外排泵基因adeB的表达水平。结果替加环素对100株受试菌的最低抑菌浓度(MIC)为0.125μg/ml^4μg/ml,MIC50为1μg/ml,MIC90为2μg/ml;菌株中ade B外排泵基因广泛分布,但adeB外排泵基因的相对表达量并未随着MIC值的增加而增加。结论多重耐药鲍曼不动杆菌对替加环素敏感性的降低可能存在ade B基因表达调控以外的机制。

Objective To explore the mechanism for decreased susceptibility to tigecycline for the mulitidrug-resistant Acinetobacter baumannii.Methods Susceptibility to tigecycline for the mulitidrug-resistant Acinetobacter baumannii was determined by E-test method.The distribution of ade B efflux pump genes among these isolates was investigated by quantitative real-time PCR.Reverse-transcription PCR method was applied to determine the expression level of ade B gene.Results Minimal inhibitory concentrations of tigecycline to the 100 strains was within 0.125 μg/ml-4 μg/ml.MIC50 and MIC90 were 1 μg/ml and2 μg/ml,respectively.The ade B was widely distributed among these strains,but the relative quantification of ade B gene expression did not increase absolutely along with MICs.Conclusion Other mechanism might be associated with decreased susceptibility to tigecycline for mulitidrug-resistant Acinetobacter baumannii.