The research on mechanism of Klebsiella pneumoniae resistant to carbapenem antibiotics

Background: To investigate the resistance mechanism of Klebsiella pneumoniae (Kpn) resistant to carbapenems. Methods: K-B assay was used to determine the susceptibility of Klebsiella pneumoniae strains to antibiotics. Six isolated strains were identified and collected, which were resistant to carbapenems using modified Hodge test. The phenotypes of metal enzyme were detected with EDTA (Ethylene diamine tetraacetic acid) disk diffusion method. The genes of beta lactamases, included KPC gene were confirmed. Results: The six carbapenems resistant strains of Klebsiella pneumoniae were resistant to imipenem, meropenem, aztreonam, etc., but sensitive to amikacin, fosfomycin, minocycline, and polymyxin. The metal enzyme could not be produced by these six pathogens, but all these six strains could produce carbapenemases. Moreover, the six strains partically carried with blaTEM or blaSHV, but all with blaKPC-2. Conclusion: We thought that the key factor of the resistance mechanism to carbapenem for Klebsiella pneumoniae maybe these pathogens contain blaKPC-2 gene.