临床分离大肠埃希菌耐药性分析及I型整合子研究

目的了解临床分离大肠埃希菌对常用抗菌药物的耐药状况；研究整合子在大肠埃希菌中的分布情况，探讨其与大肠埃希菌耐药性之间的相关性。方法收集广东省3所医院2010-2012年分离的大肠埃希菌，采用K B纸片扩散法进行药敏试验；聚合酶链反应（PCR）法扩增3类整合子整合酶基因和整合子可变区，测序分析整合子所携带的耐药基因盒类型。结果共收集156株大肠埃希菌，其对青霉素类、头孢菌素类、氟喹诺酮类、氨基糖苷类和磺胺类等的大多数抗菌药物的耐药率＞50%；耐药率＜10%的抗菌药物有头孢哌酮/舒巴坦（0）、亚胺培南（3.85%）、头孢替坦（4.35%）、厄他培南（7.69%）和哌拉西林/他唑巴坦（8.97%）；I类整合子的检出率为57.69%（90/156），多重耐药菌与非多重耐药菌的整合子检出率分别为66.00%（66/100）和64.71%（22/34），两组比较，差异无统计学意义（P＞0.05）,但分别与敏感菌组（9.09%，2/22）相比，差异均有统计学意义（P＜0.01）。所检出的整合子可变区分为9种类型，大部分都含有aadA和dfrA耐药基因盒。结论大肠埃希菌整体耐药情况严重；I类整合子在临床分离大肠埃希菌中分布广泛，并与大肠埃希菌的耐药性关系密切，主要介导对氨基糖苷类、磺胺类、β 内酰胺类等多种抗菌药物的耐药性。

Antimicrobial resistance analysis on clinically isolated Escherichia coli and detection of class I integrons

Objective To study antimicrobial resistance of clinically isolated Escherichia coli（E.coli）,the prevalence of integrons in E.coli,and relation of integron with antimicrobial resistance of E.coli.Methods E.coli isolated from three hospitals of Guangdong Province from 2010 to 2012 were collected,and antimicrobial susceptibility testing was performed by Kirby-Bauer method;integrons were detected by polymerase chain reaction（PCR）,and gene cassette was analyzed by sequencing.Results A total of 156 E.coli isolates were collected,antimicrobial susceptibility testing showed that resistance rate of E.coli to most penicillins,cephalosporins,fluoroquinolones,aminoglycosides and sulfonamides were over 50%;the resistance rate to antimicrobials〈10% included cefoperazone/sulbactam（0）,imipenem（3.85%）,cefotetan（4.35%）,ertapenem（7.69%）and piperacillin/tazobactam（8.97%）;The positive rate of class I integron was 57.69%（90/156）;the positive rate of class I integron in multidrug-resistant and non-multidrug-resistant E.coli was 66.00%（66/100）and64.71%（22/34）respectively,the difference was not statistically different（P〉0.05）,but compared with sensitive E.coli（9.09%,2/22）,the difference was statistically different（P〈0.01）.There were nine types of integron-drug resistant gene cassettes in the variable regions,most of which contained aadAand dfrA.Conclusion Antimicrobial resistance of E.coli is serious;high incidence of class I integrons are widely found in E.coli,and is closely related with drug resistance of E.coli,class I integrons mainly mediated aminoglycosides,sulfonamides and beta-lactams resistance.