铜绿假单胞菌整合子基因盒的相关研究

Study on the integrons and integrated gene cassettes in Pseudomonas aeruginosa

目的对北京大学人民医院不同年度临床分离的铜绿假单胞菌进行整合子基因盒检测,分析其变化趋势及其与细菌耐药性的相关性。方法应用PCR对2006—2008年临床分离的420株铜绿假单胞菌进行整合子检测,对阳性PCR产物采用HinfⅠ内切酶作限制片段多态性(RFLP)分析进行整合子分类,并对整合子阳性株进行耐药基因盒的扩增与测序。结果 420株铜绿假单胞菌中116株(27.6%)检出Ⅰ类整合子,未检出Ⅱ、Ⅲ类整合子。对2006年及2008年的整合子阳性菌株可变区基因盒扩增得到7种不同的基因盒图谱,片段大小在710～2526bp,基因盒为介导氨基糖苷类抗生素耐药的aadB、aadA族和介导甲氧苄啶耐药的dfrA1和dhfrXVB。结论该院铜绿假单胞菌中整合子检出率随年度呈上升趋势,携带的基因盒与其耐药表型有相关性。

Objective To examine the integrons and integrated gene cassettes in Pseudomonas aeruginosa isolated in Peking University People＇s Hospital （2006 2008） and analyze their effects on antibiotic resistance. Methods Kirby-Bauer susceptibility method was used to analyze the 420 clinically isolated strains of P. aeruginosa. PCR amplification using specific primers was performed to screen integrons and integrated gene cassettes from the integron positive strains. Results The integrons were identified in 116 of the 420 isolates （27.6 %）. All integrons were class I as determined by RFLP analysis. Neither class Ⅱ nor class Ⅲ integron was detected. Seven different gene cassettes were identified in the strains isolated during 2006 and 2008. Their length was between 710 bp and 2 526 bp. Sequencing analysis revealed that they are aad family, dfrAl and dhfrXVB. Conclusions The prevalence of integrons in P. aeruginosa is increasing during 2006 and 2008. Gene cassettes in integron are associated with antibiotic resistance.