鲍曼不动杆菌碳青霉烯酶和RND外排泵相关耐药基因的研究

Study on carbapenemase and RND efflux pump related drug resistance genes in Acinetobacter baumannii

目的分析鲍曼不动杆菌的碳青霉烯酶和RND外排泵基因的携带情况,并进一步探讨外排泵过表达与菌株耐药性形成的关系。方法采用PCR技术扩增分离鲍曼不动杆菌的B类金属酶(blaNDM-1、blaVIM、blaIMP)、D类苯唑西林酶(blaOXA-23、blaOXA-24、blaOXA-51、blaOXA-58)以及RND外排泵基因(adeB、adeJ、adeG),再采用qPCR对6株多重耐药鲍曼不动杆菌(MDRAB)和4株非多重耐药鲍曼不动杆菌(NMDRAB)菌株的adeB、adeJ和adeG水平进行检测。结果71株MDRAB中blaNDM-1(26.8%,19/71)、blaIMP(88.7%,63/71)和blaOXA-23(84.5%,60/71)的检出率明显高于30株NMDRAB中blaNDM-1(0.0%,0/30)、blaIMP(0.0%,0/30)和blaOXA-23(10.0%,3/30)的检出率,差异均有统计学意义(P<0.05)。blaOXA-51的检出率为100.0%,未检测到blaVIM、blaOXA-24和blaOXA-58。71株MDRAB中adeB(98.6%,70/71)和adeG(100.0%,71/71)的检出率显著高于30株NMDRAB中adeB(20.0%,6/30)和adeG(90.0%,27/30)的检出率,差异均有统计学意义(P<0.05);adeJ的检出率为100.0%;同时MDRAB菌株的adeB和adeG基因表达量明显高于NMDRAB菌株(P<0.05)。结论碳青霉烯酶基因NDM-1、IMP和OXA-23和外排泵adeABC、adeFGH的高表达与鲍曼不动杆菌多重耐药的形成关系密切。

Objective To analyze the carrying situation of carbapenemase and RND efflux pump genes in Acinetobacter baumannii,and to further explore the relationship between the efflux pump overexpression and drug resistance formation of strains.Methods PCR was adopted to amplify the class B metalloenzyme(blaNDM-1,blaVIM and blaIMP),class D oxacillinase(blaOXA-23,blaOXA-24,blaOXA-51 and blaOXA-58)and RND efflux pump genes(adeB,adeJ and adeG)of the isolated strains.Then the expression level of adeB,adeJ and adeG of 6 strains of multidrug-resistant Acinetobacter baumannii(MDRAB)and 4 strains of nonmultidrug-resistant Acinetobacter baumannii(NMDRAB)were detected by qPCR.Results The detection rates of blaNDM-1(26.8%,19/71),blaIMP(88.7%,63/71)and blaOXA-23(84.5%,60/71)in 71 strains of MDRAB were significantly higher than those of blaNDM-1(0.0%,0/30),blaIMP(0.0%,0/30)and blaOXA-23(10.0%,3/30)in 30 strains of NMDRAB,and the differences were statistically significant(P<0.05).The detection rate of blaOXA-51 was 100.0%,blaVIM、blaOXA-24 and blaOXA-58 were not detected.The detection rate of adeB(98.6%,70/71)and adeG(100.0%,71/71)in 71 strains of MDRAB was significantly higher than those of adeB(20.0%,6/30)and adeG(90.0%,27/30)in 30 strains of NMDRAB,and the differences were statistically significant(P<0.05).The detection rate of adeJ was 100.0%.At the same time,the gene expression levels of adeB and adeG in MDRAB strains were significantly higher than those in NMDRAB strains(P<0.05).Conclusion The high expressions of carbapenemase genes NDM-1,IMP and OXA-23 and the efflux pump adeABC and adeFGH are closely related to the multidrug resistance formation in Acinetobacter baumannii.