铜绿假单胞菌整合子分布及基因盒携带情况分析

Prevalence of integrons and inserted gene cassettes in clinical isolates of Pseudomonas aeruginosa

目的了解烟台地区临床分离铜绿假单胞菌整合子的分布及耐药基因盒携带情况,探讨整合子与菌株耐药的相关性。方法菌株鉴定及药敏试验采用VITEK2全自动细菌分析仪。整合子及可变区检测采用PCR法,并采用限制性片段长度多态性分析和测序分析进一步确定可变区耐药基因盒类型。结果在100株铜绿假单胞菌中38株(38%)检出Ⅰ类整合子,未检出Ⅱ、Ⅲ类整合子。Ⅰ类整合子常见基因盒类型为aac(6′)Ⅱ-aadA13-clmA8-oxA10a和aac(6′)Ⅱ-aadA13-oxA10a,其中aac(6′)Ⅱ-aadA13-oxA10a基因盒为首次出现的新基因盒排列方式,并已登录Genbank:JN118546。结论烟台地区铜绿假单胞菌整合子类型分布为Ⅰ类整合子,整合子携带菌株与铜绿假单胞菌耐药密切相关。

Objective To investigate the prevalence of integrons and the inserted gene cassettes in clinical isolates of Pseudomonas aeruginosa from Yantai and to discuss the correlation between integrons and drug resistance.Methods Identification of bacteria strains and antimicrobial susceptibility tests were performed by using VITEK2 system.Integrons and variable regions were detected by polymerase chain reaction（PCR） and inserted gene cassettes were further determined by restriction fragment length polymorphism（RFLP） analysis and sequencing.Results Of the 100 clinical isolates of Pseudomonas aeruginosa,38 isolates（38%） carried class Ⅰ integrons and no isolates carried either class Ⅱ or Ⅲ integrons.Among the isolates carrying class Ⅰ integrons,the common gene cassette arrays were aac（6’）Ⅱ-aadA13-clmA8-oxA10a and aac（6’）Ⅱ-aadA13-oxA10a,of which the latter array containing aac（6’）Ⅱ-aadA13-oxA-10a genes was a novel gene cassette arrangement,whose sequence had been assigned to the Genbank with accession number：JN118546.Conclusion Class Ⅰ integrons might be the prevalent integron types in Yantai,which could be closely related to drug resistance in clinical isolates of Pseudomonas aeruginosa.