A preliminary study on the relationship between Class I integrase and resistance of Escherichia coli

OBJECTIVE To investigate the changes of antibiotic resistance of Escherichia coli isolates and the distribution of class Ⅰ integrase genome among all ESBL-producing and non-ESBL-producing E.coli isolates and to evaluate the association between class Ⅰ integrase and ESBL-producing organisms.METHODS The presence of ESBLs-producing isolates were determined by the standard double-disk synergy test according to CLSI 2010 and the class Ⅰ integrase genome was determined by Polymerase Chain Reaction(PCR) with integrase specific primer.Statistical significance for comparison proportions was calculated by the chi-square test.RESULTS These E.coli strains showed low rates of antibiotic resistance to imipenem,cefoperazone/sulbactam,piperacillin/tazobactam and nitrofurantoin but high rates to others antibiotics in past 5 years.However,imipenem showed good antimicrobial activity among all these strains.A slightly descendent tendency appeared in part of aminoglycosides.104 of 150 isolates were identified being positive for class Ⅰ integrase gene.The class Ⅰ integron was found among ESBL-producing(71.8%) and non-ESBL-producing(66.6%) E.coli strains(P0.05).The aminoglycosides resistance of class 1 integrase gene positive strains were higher than that of the negative strains(P0.05).CONCLUSION To most antibiotics,a slightly elevatory resistant tendency was showed in E.coli strains isolated from clinical patients in 5 years.Our experimental data shows that perhaps there were no relationships between integron-carrying and the ESBLs-producing in these strains.The antibiotics resistance for most of the integrase positive strains was higher than that of negative ones and surveillance for antibiotic resistance of these strains should be enhanced.