泛耐药鲍氏不动杆菌获得性耐药基因的指标聚类分析

Index cluster analysis of acquired resistance genes in pandrug-resistant Acinetobacter baumannii

目的调查一组泛耐药鲍氏不动杆菌获得性耐药相关基因与可移动遗传元件的关系,以了解它们之间是否存在关联。方法收集2010年7-12月某医院住院患者痰标本中分离的泛耐药鲍氏不动杆菌共20株,用gyrA和parC基因的分子鉴定法鉴定菌种,再用聚合酶链反应(PCR)方法分析50种水平转移获得的β-内酰胺类、氨基糖苷类获得性耐药基因和13种接合性质粒、转座子、插入序列、整合子等可移动遗传元件遗传标记检测等。结果 20株泛耐药鲍氏不动杆菌共检出5种获得性β-内酰胺类耐药基因、5种获得性氨基糖苷类耐药基因、2种抗菌制剂外排泵基因、5种可移动遗传元件的遗传标记,连锁检测ISaba1-ADC、ISaba1-OXA-23均呈阳性,而ISaba1-OXA-66均呈阴性;获得性耐药基因TEM-1、ADC、OXA-23、OXA-66、ant(3")-Ⅰ、aph(3')-Ⅰ,adeB、qacE△1与可移动遗传元件intⅠ1、tnpU、tnp513、IS26、ISaba1高度相关。结论泛耐药鲍氏不动杆菌获得性耐药基因与可移动遗传元件一定的关联度,菌株携带的获得性耐药基因可能由可移动遗传元件介导。

OBJECTIVE To investigate the correlation between acquired resistance genes and mobile genetic ele- ments was a group of pandrug-resistant Acinetobacter baurnannii so as to determine whether there was a relation- ship between them. METHODS From Jul 2010 to Dec 2010, a total of 20 strains of pandrug-resistant A. baumannii were isolated from the sputum specimens obtained from hospitalized patients, then the identification of the strains was performed with the use of molecular identification of gyrA and parC genes, and the polymerase-chain-reaction （PCR） was used to analyze the 50 kinds of acquired resistance genes to beta-lactams and aminoglycosides as well as 13 kinds of mobile genetic markers such as the conjugal plasmids, transposons, insertion sequences, and inte- grons. RESULTS Totally 5 kinds of acquired beta-lactam-resistance genes, 5 kinds of acquired aminoglycoside-re- sistance genes, 2 kinds of drug inhibitor efflux pump genes, and 5 kinds of genetic markers of mobile genetic ele- ments were tested positive in the 20 strains of pandrug-resistant A. baurnannii. Furthermore, the linkage detection was positive {or both ISabal-ADC and ISabal-OXA-23, negative for ISabal-OXA-66. The index cluster analy- sis showed that high-level correlation existed between the acquired resistance genes （TEM-1, ADC, OXA-23, OXA- 66, ant （3＂） - I , aph （3＇） - I , adeB, qacE△ 1） and the genetic markers of mobile genetic elements （int I 1, tnpU, tnp513, IS26, ISabal）. CONCLUSION In this group of pandrug-resistant A. baurnannii, certain correla- tion exists between the acquired resistance genes and the mobile genetic elements, and the acquired resistance genes carried by the strains may be mediated by the mobile genetic elements.