title: [Prevalence of plasmid-mediated AmpC beta-lactamases in Escherichia coli and Klebsiella spp. isolated in children].
abstract: OBJECTIVE
  To study the plasmid-mediated AmpC β-lactamases and the genotypes of Escherichia coli and Klebsiella spp. in children.
  
  
  METHODS
  Escherichia coli and Klebsiella spp. of strains were isolated at our division from January to December 2009. Cefoxitin disk diffusion method was used to screen Escherichia coli and Klebsiella spp. for phenotypic AmpC enzyme. Multiple PCR method was adopted to test the genotypes of AmpC enzyme-positive Escherichia coli and Klebsiella spp.strains.
  
  
  RESULTS
  Of all Escherichia coli and Klebsiella spp., 65 were insensitive to cefoxitin disk and 17 strains carried DHA type AmpC gene. The prevalence of plasmid-mediated AmpC enzyme in Escherichia coli and Klebsiella spp. was 26.2% (17/65). Among plasmid-mediated AmpC enzyme isolates, 14 (38.9%) Klebsiella pneumoniae strains, 2 (7.7%) Escherichia coli strains and 1 (33.3%) Klebsiella oxytoca strains carried the DHA-1 AmpC gene. The genes of MOX, CIT, DHA, ACC, MIR and FOX were not found in other 48 strains.
  
  
  CONCLUSIONS
  The identified plasmid-mediated AmpC genes are all of DHA-1 genotype in Escherichia coli and Klebsiella spp. The prevalence of plasmid-mediated AmpC enzyme in Klebsiella pneumoniae isolates is relatively high in children.
authors.affiliation: Division of Bacteriology, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China. fangd32@yahoo.com.cn
authors.forename: Fang
authors.initials: F
authors.lastname: Dong
authors.forename: Xi-wei
authors.initials: XW
authors.lastname: Xu
authors.forename: Wen-qi
authors.initials: WQ
authors.lastname: Song
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification; D002648:Child; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D005838:Genotype; D006801:Humans; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D010957:Plasmids; D016133:Polymerase Chain Reaction / Q000379:methods; D001618:beta-Lactamases / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D001426:Bacterial Proteins; C048795:AmpC beta-lactamases; D001618:beta-Lactamases