Detection and analysis of the resistance and prevalence of extended-spectrum β-lactamases and AmpC genes in Klebsiella pneumoniae

Objective To investigate the resistance and prevalence of extended-spectrum β-lactamase and AmpC β-lactamase in K.pneumoniae in lower piratory tract infection,and to study the genotyping of AmpC β-lactamase.Methods Disc diffusion confirmatory test was used to detect ESBLs,three dimensional test was used to detect AmpC,PCR was used to determine the genotype of AmpC,DNA sequencing were performed to determine the subtypes of AmpC β-lactamase,antimicrobial susceptibility was tested by Kirby-bauer method.Results Among the 58 K.pneumoniae strains in lower respiratory tract infection,there were ESBLs in 21 strains,AmpC in 5 strains,ESBLs and AmpC simultaneously occurred in 3 strains.Among the 5 AmpC positive stains,there were DHA-1 in 4 strains,MIR in 1 strains.β-lactamases positive strains were more resistant to antibiotics than β-lactamases negative strains.Conclusions ESBLs and AmpC in K.pneumoniae have a high detectable rate,and DHA-1 was the main genotyping of AmpC.Producing ESBLs and AmpC enzyme was a prominent cause of resistance in K.pneumoniae.