Study on resistant mechanism of carbapenem resistant Klebsiella pneumoniae and Escherichia coli

Objective To investigate the drug resistance and the resistant mechanism of suspicious carbapenemases in Klebsiella pneumoniae and Escherichia coli clinical isolates. Methods All bacteria were isolated from the First Affiliated Hospital of Guangzhou Medical College, and antimicrobial susceptibility was done by VITEK-2 automatic bacterium identifying and drug sensitivity analyzing systems. The screening of the carbapenemase was detected by the modified Hodge test, and the polymerase chain reaction (PCR) was carried out to amplify carbapenem hydrolyzing gene( KPC), outer membrane protein genes (OmpK35 and OmpK36), transposon tnpA and tnpU. Results Among 47 strains of suspicious carbapenemases in Klebsiella pneumoniae and Escherichia coli, the higher drug resistance rates to them were penicillins, cephalosporins and quinolones, which were more than 80%. The resistance rates for imipenem, meropenem and amikacin were less than 35%. In addition to the imipenem-resistant strains, the resistance rates to cefoperazone