Analysis of drug resistance genes in extended spectrum β-lactamases producing Escherichia coli

Objective To investigate the genotypes prevalence of extended spectrum B-lactamases(ESBLs)and aminog lycoside modifying enzymes(AM Es)in ESBLs producing Escherichia coli clinical strains.Methods Kirby-Baucer method was performed to test the antibiotics susceptibility of 49 ESBLs pro ducing Escher ichia coli strains.Genot ypes of ESBLs and AMEs were analyzed by PCR method.Results The 49 clinical strains were all multiple resistant.The resistance rate to ampicillin,cefazolin,cefoper azone and ceftriaxone was more than 90%.The resistance rates to gentamicin and tobramycin were 67.3% and 65.3% respectively.The resistance rate to meropenem was the lowest,only 2.0%.The positive rate of ESBLs g enes of blaTEM,blaSHV,blaCTX-M-1 and blaCTX-M-9 was 9319%,2.2%,2215% and 59.2%,respectively.The positive rate of AMEs genes of aac(3)-Ⅱ,aac(6c)-Ⅰ and ant(3d)-Ⅰ was 61.2%,30.6% and 18.4%,respectively.Conclusion Multiple resistance of ESBLs producing Escher ichia coli clinical strains was serious.Different genotypes of ESBLs and AM Es were of ten coexistent in the same strain and the most popular coexist ence way was blaT EM,blaCT X-M-9 and aac(3)-Ⅱ.