STUDY ON DRUG RESISTANCE OF EXTENDED SPECTRUM BETA-LACTAMASES-PRODUCING STRAINS OF Escherichia coli

[Objective]To investigate the isolated rate of extended spectrum beta-lactamases carried in Escherichia coli among Tongji Hospital,Huazhong University,and analysis the drug resistance to 15 kinds of antibacterial agents of E.coli.[Methods]A total of 468 strains of Escherichia coli were collected from Tongji hospital affiliated to HuaZhong University of science and technology.The MIC of 15 antibacterial agents against the clinical isolates was detected by double agar dilution method.[Results]153 ESBLs-producing strains were detected in 468 Escherichia coli.The detection rate was 32.7%.For the second generation cephlosporins,the drug resistance rates of the 153 E.coli strains of ESBLs producers were more than 90%.For other cephlosporins,the drug resistance rates were from 12.5% to 55%.For gentamicin,Ciprofloxacin,and tetracycline,the rates of drug resistance were from 70% to 90%.MIC50 of ceftazidime and amikacin were in the range of susceptibility.For aztreonam,MIC50 reached to the rang of intermediary.MIC50 and MIC90 for other antibacterial agents were in the range of resistance.However,all of these ESBLs producers were susceptible to imipenem.The differences in antimicrobial resistance for ESBLs-producing E.coli and non ESBLs-producing E.coli were not statistically significant for amikacin and tetracycline,but were statistically significant for other antibacterial agents[Conclusion]The isolation rates of ESBLs producing in E.coli is 32.7%.Extended spectrum beta-lactamase producers reveal high drug resistance to most of the antibacterial agents.All of these detected strains are only susceptible to imipenem.