Investigationthe Mechanism Of Carbapenemase-Producing And Homology Of Carbapenem Resistant Klebsiella Pneumoniae

Objective:To provide evidence for the clinical treatment and control of carbapenem resistant Klebsiella pneumoniae (CRKP). The carbapenemase-producing Klebsiella pneumonia was screened from a grade three hospital in Chongqing. The phenotype and genotype of carbapenemases and the homology of carbapenem resistant Klebsiella pneumonia were analyzed.Methods:A total of 200 Klebsiella pneumoniae strains were collected from a grade three hospital in Chongqing from 2003 to 2013. The strains were identified through amplification of the khe gene by PCR. The CRKP were screened by antibiotic sensitivity test and MIC. Modified Hodge test and modified Carba test NP were used to screen strains producing carbapenemase. The carbapenemase-coding genes were amplified by PCR and sequenced. The transferability of the drug resistance genes were detected through plasmid conjugation experiment.The bacterial homology analysis was carried out by using MLST and PFGE methods.Results:A total of 22 clinical CRKP were screened and the most of them were not sensitive to ertapenem. Among them,6 strains produced B enzyme and the resistance gene analysis showed 6 strains carried resistant gene including 1 strain carrying NDM-1 gene,1 strain carrying IMP-4 gene,4 strains carrying IMP-8 gene. The plasmid conjugation experiments of 6 strains were successfully. The MLST and PFGE molecular typing test showed 6 strains of CRKP have 4 STs genotypes and a number of bands in PFGEConclusion:CRKP has multiple resistance mechanisms and carbapenemases-producing is one of the most common mechanisms of resistance. The carbapenemases-producing strains carry resistance genes IMP-8, IMP-4, OXA-1 in this hospital, and resistant gene can be transferred by plasmid. MLST and PFGE results showed the hospital has the main epidemic strains that should be pay more attention to avoid the outbreak ofnosocomial infections.