尿液分离大肠埃希菌Ⅰ类整合子分子特征与耐药性的关系研究  

Molecular characteristics of typeⅠintegrons in Escherichia coli isolated from urine and correlation with drug resistance

作　　者：姜波 魏取好[2] 吕火祥[2] 

机构地区：[1]湖州市南浔区人民医院,浙江湖州313009 [2]浙江省人民医院医学检验中心,浙江杭州310014

出　　处：《中华医院感染学杂志》2014年第1期5-8,共4页Chinese Journal of Nosocomiology

基　　金：浙江省自然基金资助项目(Y2110743)

摘　　要：目的了解社区感染尿液分离大肠埃希菌中Ⅰ类整合子的分布,并分析其与细菌耐药性的关系。方法选取114株临床非重复分离自医院门诊患者尿液标本中的大肠埃希菌,经全自动细菌分析系统鉴定并检测其对临床常用抗菌药物的耐药性,聚合酶链反应(PCR)检测Ⅰ类整合酶基因,对Ⅰ类整合酶阳性菌株用PCR扩增并测序分析可变区基因盒种类。结果 114株临床非重复分离自尿液大肠埃希菌中有50株检测到Ⅰ类整合酶基因;共检测出两种不同长度的可变区片段:1 700bp片段(30株)为dfrA17-aadA5,2 100bp片段(5株)为dfrA12-orfF-aadA2,有两株大肠埃希菌同时扩增出1 700bp和2 100bp的可变区片段,有17株Ⅰ类整合酶基因阳性大肠埃希菌未扩增出可变区;114株大肠埃希菌对氨苄西林、磺胺甲噁唑/甲氧苄啶和左氧氟沙星的耐药率较高,>50.0%,对头孢替坦、亚胺培南、厄他培南、哌拉西林/他唑巴坦、呋喃妥因、阿米卡星耐药率较低,<5.0%;Ⅰ类整合子阳性菌株对氨苄西林、庆大霉素、妥布霉素和磺胺甲噁唑/甲氧苄啶的耐药率高于Ⅰ类整合子阴性菌株。结论与医院感染相比,社区感染尿液中分离的大肠埃希菌受抗菌药物的选择压力相对较小,其对常用抗菌药物的耐药率、Ⅰ类整合子携带率均较低,同时Ⅰ类整合子中携带的基因盒种类也较单一。OBJECTIVE To investigate the distribution of type Ⅰintegrons in the Escherichia coli isolated from urine of the patients with community-acquired infections and analyze the correlation with drug resistance. METHODS Totally 114non-repeated isolates of E.coli were collected from urine specimens obtained from the outpatient department,then the drug resistance to the commonly used antibiotics was determined with the use of automatic bacterial analysis system,the typeⅠintegron integrase genes（intI1）were screened by polymerase-chainreaction（PCR）,and the inserted gene cassettes of variable regions inintI1-positive isolates were detected by using PCR combined with sequence analysis.RESULTS Among the 114clinical isolates of non-repeated E.coli from urine,50isolates have been detected positive for the intI1;two types of variable fragments of different lengths were detected in intI1-positive isolates：1 700bp fragment（30strains）identified as the gene cassette array dfrA17-aadA5,2 100bp fragment（5strains）defined as the gene cassette array dfrA12-orfF-aadA2.Both 1 700bp and 2 100bp fragments were detected in two strains,and the variable regions of typeⅠintegrons were failed to be amplified in 17strains.The drug resistance rates of the 114isolates of E.coli to ampicillin,sulfamethoxazole-trimethoprim,and levofloxacin were more than 50.0%,while the drug resistance rates to cefotetan, imipenem,ertapenem,piperacillin-tazobactam,furantoin,and amikacin were less than 5.0%;the drug resistance rates of the intI1-positive strains to ampicillin,gentamicin,tobramycin,and sulfamethoxazole-trimethoprim were higher than those of the intI1-negative strains.CONCLUSIONAs compared with the E.coli causing nosocomial infections,the E.coli causing the community-acquired infection is more susceptible to the commonly used antibiotics,with thepositive rate of typeⅠintegrons lower,in addition,the categories of gene cassettes detected in type Ⅰintegrons are very limited.

关 键 词：Ⅰ类整合子 基因盒 耐药性 

分 类 号：R378.21[医药卫生—病原生物学]