Abstract:Abstract: Objective: To investigate the mechanism of plasmid-mediated resistance in one strain of pandrug resistant Klebsiella pneumonia (PRKP). Methods: The susceptibility of the PRKP strain was determined by the disk diffusion method and the automated microbroth dilution. PCR was used to identify the carbapenemase genes, including GES-1~GES-9, GES-11, OXA-48-like, IMP, VIM, KPC-1~KPC-5 and NDM, and the replicase gene repA of broad-host-range plasmid IncN in the PRKP strain. Then, the plasmid in the PRKP strain was extracted, and isolated by agarose gel electrophoresis. After the conjugation and transformation experiments were performed, the carbapenemase genes and repA in the conjugant were detected by PCR. Results: The pIncN-XM and pKPC-XM plasmids were isolated from the PRKP strain. The pIncN-XM could be transferred into E. coli J53 by the conjugation, which was an IncN-like plasmid and carried quinolone-resistant genes. However, the pKPC-XM carrying the bla>sub>KPC-2 gene was unable to be transferred into E. coli J53 but into E. coli DH5α by the transformation. Conclusion: The pandrug resistance mechanism of the PRKP may be closely related to the presence of two harbored plasmids, one carrying bla>sub>KPC-2 gene, and the other carrying quinolone-resistant genes and with IncN like feature.