The carbapenem-resistance mechanism and homology analysis of four strains of Klebsiella pneumoniae isolated from different sites of one patient / 中国感染与化疗杂志

ABSTRACT

Objective To study the drug resistance mechanism and homologous relationship of four clinical strains of carbapen-em-resistant Klebsiella pneumoniae isolated from different sites of the same one patient.Methods Four carbapenem-resistant K .pneumoniae strains were isolated from blood,urine,sputum and pelvic drainage of a patient after cystectomy in clinical mi-crobiology lab of Xinhua Hospital in March 2012.① Modified Hodge test was used to detect the expression of carbapenemase.② PCR amplification assay and DNA sequencing were used to detect resistance-related genes.③ SDS-PAGE analysis was per-formed to analyze outer membrane porin components of the four carbapenem-resistant K .pneumoniae isolates.ERIC-PCR as-say was used to analyze the homology of these carbapenem-resistant isolates.Results Modified Hodge test demonstrated that all the four carbapenem-resistant K.pneumoniae expressed carbapenemase.KPC-2 gene was identified in all the four isolates by PCR test and DNA sequencing.SDS-PAGE analysis indicated an outer membrane porin alteration common to all the four iso-lates which is distinct from that of the strain sensitive to antibiotics.The identical DNA fingerprinting of the four strains was confirmed by ERIC-PCR analysis.Conclusions The antibiotic resistance mechanism of the four carbapenem resistant K.pneu-moniae associated with this case includes the expression of KPC-2 and altered outer membrane permeability induced by abnormal expression of outer membrane porin.These four strains belong to one common clonal group.