广泛耐药鲍曼不动杆菌氨基糖苷类药物获得性耐药基因研究

The study of acquired resistant genes against aminoglycosides in extensively drug-resistant Acinetobacter baumannii

目的了解重症监护病房(ICU)患者分离的广泛耐药(XDR)-鲍曼不动杆菌(AB)对氨基糖苷类药物获得性耐药基因情况。方法用phoenixTM-100全自动细菌鉴定药物敏感性分析仪对AB进行细菌鉴定和药物敏感性试验,gyrA和parC基因扩增测序确定AB。聚合酶链反应(PCR)测定20株XDR-AB的10种氨基糖苷类修饰酶基因、6种16S rRNA甲基化酶基因和外排泵adeB基因,并用DNA测序比对。结果 20株XDR-AB中,氨基糖苷类修饰酶基因aac(3)-Ⅰ、aac(6')-Ⅰb、ant(3″)-Ⅰ、aph(3')-Ⅰ检出率分别为90.0%、30.0%、95.0%、95.0%,而aac(3)-Ⅱ、aac(6')-Ⅰad、aac(6')-Ⅱ、ant(2″)-Ⅰ、ant(4')-Ⅰ及aph(3')-Ⅵa基因均未检出。armA型16S rRNA甲基化酶基因和外排泵adeB基因检出率均为100%。结论 20株XDR-AB均携带了armA和adeB基因,同时aac(3)-Ⅰ、ant(3″)-Ⅰ和aph(3)-Ⅰ检出率较高,提示ICU分离的XDR-AB对氨基糖苷类药物高水平耐药可能与携带的耐药基因有关。

Objective To investigate the situation of acquired resistant genes against aminoglycosidcs in extensively drug-resistant （XDR） Acintobacter baumannii （AB） isolated from intensive care unit （ICU） patients. Methods Bacterial identification and susceptibility tests of AB were performed by phoenixTM-100 automatic bacterial identification and susceptibility analyzer, and the AB identification was confirmed by gyrA and parC gene amplification sequencing. For the 20 isolates of XDR-AB, 10 aminoglyeoside modifying enzyme genes, 6 16S rRNA methylase genes and efflux pump adeB genes were detected by polymerase chain reaction（PCR） and verified and compared by DNA sequencing. Results Of the 20 isolates of XDR-AB, the detection rates of aac （ 3 ） - I , aac （6＇） - Ib, ant （ 3 ＂） - I and aph （ 3＇ ） - I genes were 90.0% , 30.0%, 95.0% and 95.0% , respectively. However, aac （ 3 ） - I1 , aac （ 6＇ ） - I ad , aac （ 6＇ ） - Ⅱ , ant （2＂）- I , ant （4＇）- I and aph （3＇）- Via genes were not found. In addition, the armA 16S rRNA methylase gene and efflux pump adeB genes existed in all of the 20 isolates, and the detection rates were 100%. Conclusions All of the 20 isolates of XDR-AB carry not only armA and adeB genes but also a large amount of aac（ 3 ） - I ,ant（3＂） - I and aph（ 3 ） - I genes. It indicates that the high-level resistance to aminoglycosides in XDR-AB isolated from ICU may be associated with the resistant genes.