Stability of vancomycin-resistant enterococcal genotypes isolated from long-term-colonized patients

J Infect Dis. 1998 Feb;177(2):378-82. doi: 10.1086/514196.


Genotypic variation and stability of isolates of vancomycin-resistant enterococci (VRE) were studied to determine genetic diversity and whether strain definition based on pulsed-field gel electrophoresis (PFGE) is applicable to an endemic setting. Twenty-two PFGE types were identified among 455 VRE isolates. One-on-one comparisons of 10 vanA Enterococcus faecium strain types all yielded > 10 band differences. Variations among vanA and vanB E. faecium isolates from individual long-term-colonized (4-160 days) patients yielded < 3 band differences for > 85% of comparisons. Comparison of all strains without grouping by vancomycin resistance types yielded two peaks of band differences: one with < 3 and one with > 10 band differences. These data show that VRE isolates were genetically closely related or very different; demonstrate that within individual patients, VRE isolates show little genetic variation; and provide empirical evidence that PFGE can be used to study the epidemiology of VRE endemicity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • DNA, Bacterial / analysis
  • DNA, Bacterial / genetics
  • Drug Resistance, Microbial / genetics*
  • Electrophoresis, Gel, Pulsed-Field
  • Enterococcus / drug effects
  • Enterococcus / genetics*
  • Enterococcus faecium / drug effects
  • Enterococcus faecium / genetics
  • Genetic Variation
  • Genome, Bacterial
  • Gram-Positive Bacterial Infections / drug therapy*
  • Gram-Positive Bacterial Infections / epidemiology
  • Gram-Positive Bacterial Infections / genetics*
  • Humans
  • Microbial Sensitivity Tests
  • Molecular Epidemiology
  • Population Surveillance
  • Prevalence
  • Vancomycin / pharmacology*


  • Anti-Bacterial Agents
  • DNA, Bacterial
  • Vancomycin