多重耐药铜绿假单胞菌整合子中发现2种新基因盒组合形式

目的研究多重耐药铜绿假单胞菌携带整合子的类型及耐药基因组合。方法 PCR检测多重耐药铜绿假单胞菌整合酶基因intI 1、intI 2、intI 3,Ⅰ类整合子恒定区基因qacEΔ1-sul1及可变区基因,扩增产物经胶回收、限制性片段长度多态性(RFLP)分析及基因测序分析。结果 30株临床分离铜绿假单胞菌中16株(53.3%)Ⅰ类整合酶基因及恒定区qacEΔ1-sul1基因扩增阳性,未检出Ⅱ、Ⅲ类整合酶基因。Ⅰ类整合子可变区共检出5种不同的耐药基因组合形式,含有对氨基糖苷类、β-内酰胺类和喹诺酮类抗菌药耐药的基因,其中有2种为新型基因盒组合形式,包括aacA4-VIM2和aadA2-OXA10-aacA4-blaIMP-9-aatI1,GenBank登录号分别为GQ890658和GU122165,另外3种与GenBank登录号分别为FJ917747、FJ817423、GU367339的序列基本吻合。结论多重耐药铜绿假单胞菌携带的整合子主要为Ⅰ类整合子,在Ⅰ类整合子上首次发现2种新型基因盒组合形式。

Two new gene cassette combination in multi-drug resistant Pseudomonas aeruginosa integron

Objective To investigate the carrying integron types and the gene cassette combination in multi-drug resistant Pseudomonas aeruginosa.Methods Polymerase chain reaction(PCR) were carried out to detect The integrase gene intI1,intI2 and intI3,the genes of constant and variable region of class I integron qacEΔ1-sul1 were detected by polymerase chain reaction(PCR).PCR products were purified by agarose gel.The gene cassette combination was determined by restriction fragment length polymorphism(RFLP) analysis and sequencing.Results Positive amplifications of class I integrase gene and gene qacEΔ1-sul1 were presented in 16 strains(53.3%) of 30 Pseudomonas aeruginosa isolates,but no class Ⅱ and Ⅲ integrase gene were detectable.Five different combinations of gene cassettes were found in the variable region of class I integron,in which the resistant genes for aminoglycosides,β-lactams and quinolones antibiotics were covered.Among the 5 combinations of gene cassette aacA4-VIM2 and aadA2-OXA10-aacA4-blaIMP-9-aatI1 were newly found with the accession numbers of GQ89065 and GU122165 in GenBank respectively.The other 3 gene cassette combinations were basically matched with the accession number FJ917747,FJ817423 and GU367339 respectively in GenBank.Conclusion Multi-drugs resistant Pseudomonas aeruginosa may primarily carriy class I integron,and two new gene cassette combinations were firstly found in class I integron.