A new Tn1546 type of VanB phenotype-vanA genotype vancomycin-resistant Enterococcus faecium isolates in mainland China

Diagn Microbiol Infect Dis. 2009 Jan;63(1):70-5. doi: 10.1016/j.diagmicrobio.2008.08.018.

Abstract

VanB phenotype-vanA genotype vancomycin-resistant Enterococcus faecium (VREF) has never been reported in mainland China. We investigated the frequency and molecular characteristics of this strain in a Beijing tertiary hospital. Of 23 vanA genotype VREF clinical isolates, 12 (54.3%) were VanB phenotype-vanA genotype. Mutilocus sequence typing (MLST) analysis revealed that all isolates belong to a single clonal complex (CC78), which has been disseminated worldwide. Based on MLST and pulsed-field gel electrophoresis, 23 isolates were polyclonal dissemination in our hospital. Tn1546-like element structure analysis showed that of 12 VanB phenotype-vanA genotype isolates, 5 had complete deletion of vanY and vanZ accompanying insertion of IS1216V in vanX-vanY intergenic region, 5 had ISEfa4 insertion in orf2-vanR intergenic region, a new Tn1546 structure type, and 2 were identical to VanA phenotype-vanA genotype VREF. Data showed that the deletion of vanY and vanZ genes or ISEfa4 insertion in orf2-vanR intergenic region can partly explain the causes of difference between phenotype and genotype.

MeSH terms

  • Anti-Bacterial Agents / therapeutic use
  • Bacterial Proteins / genetics*
  • Carbon-Oxygen Ligases / genetics*
  • China
  • Drug Resistance, Bacterial / genetics
  • Electrophoresis, Gel, Pulsed-Field
  • Enterococcus faecium / genetics*
  • Enterococcus faecium / isolation & purification
  • Gram-Positive Bacterial Infections / drug therapy
  • Gram-Positive Bacterial Infections / microbiology
  • Hospitals
  • Humans
  • Microbial Sensitivity Tests
  • Polymerase Chain Reaction
  • Sequence Analysis, DNA
  • Serotyping
  • Vancomycin Resistance / genetics*

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • VanA ligase, Bacteria
  • VanB protein, Enterococcus
  • Carbon-Oxygen Ligases