Isolation of carbapenemase KPC-2 producing Klebsiella pneumoniae and Pseudo-monas aeruginosa strains and resistance research / 军事医学

ABSTRACT

Objective To investigate the carbapenem-resistant mechanism of one strain of Klebsiella pneumoniae( KPN) and one strain of Pseudomonas aeruginosa( PAE) .Methods The identity of the isolates was confirmed by using MALDI-TOF mass spectrometry, 16S rDNA and special gene amplification .The minimum inhibitory concentrations (MICs) of the antimicrobial agents were determined by VITEK 2 Compact System .CarbaNP Antimicrobial susceptibility testing , plasmid extraction, electroporation experiment , PCR amplification, and cloning and sequencing were carried out to analyze the en-coding gene of β-lactamases.Results The types of β-lactamases of the KPN were blaKPC-2 and blaSHV, confirmed by se-quencing of the PCR products , and that of the PAE were blaKPC-2 .Only blaKPC-2 was displayed in both transformants .All of the results of CarbaNP were type A .Conclusion Both strains of KPN and PAE resisting to carbapenem produce a plasmid-mediated carbapenemase blaKPC-2 , which belongs to Bush group 2f, class A β-lactamase.The extended-spectrum β-lacta-mases gene encoding blaSHV of the KPN might be located in the chromosome or not in the plasmid carrying with blaKPC-2 .