Study on resistant phenotype and genotype of ESBLs-producing Escherichia coli in clinical isolates

Objective To investigate the antibiotic-resistance and the genotype of common β-lactamases of 70 extended spectrum β-lactamase(ESBLs)-producing strains of Escherichia coli in the second hospital affiliated to Wenzhou medical college.Methods Antibiotic susceptibilities of 70 ESBLs-producing strains of Escherichia coli were determined by Kirby-Bauer(K-B)test,the gene type of common β-lactamases was confirmed by polymerase chain reaction(PCR).Results The first three susceptible antimicrobial drugs for the 70 ESBLs-producing strains of Escherichia coli were imipenem(100.0%),cefoperazone-sulbactam(100.0%) and piperacillin-tazobactam(94.1%);The polyacrylamide gel electrophoresis of their PCR products revealed that 62(88.6%) strains harbored TEM type,5(7.1%) strains SHV type,1(1.4%)strain OXA type,61(87.1%) strains CTX-M type,none was for VEB and PER.Conclusions The resistant rate to most antibiotic of the 70 ESBLs-producing strains of Escherichia coli is rather high.Imipenem and cefoperazone-sulbactam are the best drug for treatment of the infection,the next is piperacillin-tazobactam;They mainly carry TEM and CTX-M resistant gene.