一株多药耐药铜绿假单胞菌整合子基因结构分析

目的 检测临床分离的72株多药耐药铜绿假单胞菌(PAE)整合子分布情况,并对其中一株vim2基因阳性菌株整合子结构及定位进行分析.方法 通过药敏试验检测铜绿假单胞菌的MIC,以PCR扩增多药耐药PAE的vim2耐药基因和Ⅰ类整合子,电泳胶回收DNA片段并测序,将测序结果以Pubmed在线软件BLAST进行序列比对分析.结果 72株非重复多药耐药铜绿假单胞菌的intI基因阳性率高达99.0％,在一株多药耐药铜绿假单胞菌(命名为PAE vim2)中检测到双整合酶,两整合酶及其相连的不同基因盒均位于细菌染色体上.其中一个结构为int Ⅰ -sul1,位于Tn21样转座子中,另一个为Tn402样的Ⅰ类整合子,后者携带vim2等基因盒.结论 多药耐药PAE整合子的携带率高,且在一株多药耐药铜绿假单胞菌中发现双整合酶耐药结构,可能是引起耐药基因水平转移的遗传物质基础.

Gene structure of double integrons from a strain of multidrug-resistant Pseudomonas aeruginosa

OBJECTIVE To detect the distribution of integrons in 72 strains of multidrug-resistant Pseudomonas aeruginosa(PAE) isolates and analyze the structure and location of integrons in one vim2-positive strain.METHODS The MIC of PAE was detected by drug susceptibility testing,PCR was used to amplify intⅠ gene and vim2 gene.The production of PCR was recovered by agar gel electrophoresis for sequencing.Then,DNA sequence was analyzed with Pubmed online software BLAST.RESULTS The positive rate of intⅠ gene was of 99.0% among those 72 non-repetition multidrug-resistant PAE isolates,and double integrase were detected in one multidrug-resistant PAE isolate(named PAE vim2),both the double integrases and their linking gene cassettes located on bacterial chromosome,one with the structure of intⅠ-sul1 located in Tn21 tranposon,the other was a Tn402-like type I integron,the latter carried with gene cassettes like vim2.CONCLUSION The rate of carrying integrons is high in multidrug-resistant PAE,double-integrases had been detected in a strains of multidrug-resistant PAE,which might be the genetic elements that facilitate horizontal transfer of resistant genes.