ABSTRACT
OBJECTIVE To investigate the genotypes of plasmid-mediated AmpC beta-lactamases carried in Klebsiella pneumoniae,to provide reasonable use of antibacterial agents and to reduce the spread of these drug resistant genes.METHODS Two hundred and eighteen strains of K.pneumoniae were performed in Tongji Hospital in Wuhan.Plasmid-mediated AmpC beta-lactamases-producing strains were screened by improved three-dimensional method and identified by multiplex PCR.DNA sequencing method was used to confirm these drug resistant strains.The MIC of 15 kinds of antibacterial agents against the clinical isolates was detected by double agar dilution method.RESULTS Thirteen strains of K.pneumoniae were detected by improved three-dimensional method.The detection rates were 5.96%.There were seven of thirteen positive strains of K.pneumoniae through improved three-dimensional method harboring DHA-1 type plasmid-mediated AmpC beta-lactamase by multiplex PCR and confirmed by DNA sequencing.Plasmid-mediated AmpC beta-lactamase producers revealed a highly drug resistance to cephalosporins,monobactams,beta-lactam/beta-lactamase inhibitor combinations,aminoglycosides and fluoroquinolones.Only imipenem was susceptible to all of these detected strains.CONCLUSIONS DHA-1 plasmid-mediated AmpC beta-lactamase is detected in K.pneumoniae strains from Tongji Hospital.The detection rate is 3.2%.The pAmpC-producing strains reveal multi-drug resistance.Only imipenem is susceptible to them.