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

Abstract:

ObjectiveTo 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. MethodsE.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. ResultsA 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) and 64.71% (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  aadA and dfrA. ConclusionAntimicrobial 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.