Detection of Extended-spectrum Beta-lactamases and its Genotypes in Escherichia coli and Klebsiella Pneumoniae Isolates in Suzhou City

Objective To investigate the ESBL-producing isolates and its resistance and genotypes in Escherichia coli and Klebsiella pneumoniae at the hospital of Suzhou city. Methods The confirmation test was used to detect ESBL-producing strains according to CLSI 2005.The MIC of 13 antimicrobials against ESBL-producing strains of Escherichia coli and Klebsiella pneumoniae were determined by 2-fold agar dilution method. PCR method was used to amplify beta-lactamases of ESBL-producing isolates by 8 premiers,PCR products were pufied and then sequencing was performed. Results The ESBL-producing rates in Escherichia coli and Klebsiella pneumoniae at the hospital of Suzhou city was 64.7% and 60.5% respectively. Resistance rates to CRO,CTX,CAZ and CIP,LEV of ESBL-producing strains were 41.9% to 86.3% and 48.4 % to 85.5%. ESBL-producing strains resistance rate to Piperacillin-tazobactam and Cefoperazone-sulbactam were 4.2 % to 25.8%;all isolates were susceptible to merpenem and imipenem. PCR indicates that the major genotypes of ESBL-producing Escherichia coli and Klebsiella pneumoniae at the hospital of Suzhou city were TEM and CHXM13; imipenem and merpenem were the best antibiotics for treatment of infections caused by ESBL-producing Escherichia coli and Klebsiella pneumoniae.Conclusions The separate rates of ESBL-producing Escherichia coli and Klebsiella pneumoniae as well as their resistance rates to cephalosporins and quinolones at the hospital of Suzhou city were very high.