Investigate The Drug Resistance Of Escherichia Coli Isolated From Clinical

Objective:To investigate the drug resistance and distribution of Extended-spectrum β-lactamases (ESBLs) producers and the characteristics of qnrA, qnrB, qnrC, qnrD and qnrS genes in nonduplicate clinical isolates of Escherichia coli (E. coli) collected from the First Affiliated Hospital of Anhui Medical University in2009.Methods:The antibacterial susceptibility results of183E. coli isolates was tested by agar dilution method, and analyzed according to the breakpoints of Clinical and Laboratory Standard Institute CLSI, ESBLs producers confirmatory tests were conducted by the CLSI phenotypic confirmatory test. QnrA, qnrB, qnrC, qnrD and qnrS were screened by Polymerase Chain Reaction (PCR). Transferability, genetic relatedness and minimal inhibitory concentrations (MICs) were examined by conjugation, ERIC-PCR and reaction of enzyme cutting, agar dilution method.Results:According to the CLSI, for most antibiotics, the resistant rate was more than50%. All the isolates were sensitive to Imlpenern.,and more than70%were sensitive to Amikacin.67.5%(123/183) E. coil were confirmed ESBLs producing. The detection rate of ESBLs producers by CTX with CTX/clavulanic acid (CTX/CLA) and CAZ with CAZ/clavulanic acid (CAZ/CLA) disks was67.2%and40.4%respectively. The prevalence of qnrA, qnrB, and qnrS genes was0.1%,0.03%, and0.1%respectively.ESBLs production was confirmed in5of these positive strains and four of.them succeed in Transfering plasmid to the recipient(J53). All qnr-positive isolates showed multiple drug resistance by MICs. The genes of ESBLs could be found in the conjugons. The result of ERIC-PCR and reaction of enzyme cutting showed that these electrophoretic bands were distinct from each other.Conclusions:The E. coil collected were multiresistant. Imlpenem were the most effective drug of treatment infections by E. coil. The prevalence of the ESBLs producers is high. And the results indicate that the eplasmids conferring resistance to quinolones and The genes of ESBLs could be transferred from donor to the recipient via plasmid with the qnr genes.There were no homology cloning in these gnr-positive strains.