Clonal dissemination and colony morphotype variation of vancomycin-resistant Enterococcus faecium isolates in metropolitan Detroit, Michigan

J Clin Microbiol. 1997 Feb;35(2):388-92. doi: 10.1128/jcm.35.2.388-392.1997.

Abstract

Thirty-two isolates of vancomycin-resistant Enterococcus faecium (VRE) recovered from 25 patients hospitalized at six hospitals in the metropolitan Detroit, Mich., area over a 32-month period were examined for relatedness by repetitive-sequence PCR (rep-PCR). All isolates were shown to carry the vanA gene by PCR. The rep-PCR patterns generated from each isolate showed that the first three VRE isolates obtained from hospital A between June 1992 and February 1994 were distinct strains. Thereafter, all VRE isolates originating from hospital A and those collected from five other area hospitals had identical rep-PCR patterns. On detailed examination, subcultures of 25 of the 32 VRE isolates produced two distinct colony types characterized phenotypically by a rough and a smooth appearance, respectively. Both colony types retained the vanA locus and the rep-PCR pattern of the primary isolate. These data suggest that a single strain of VRE with the capacity to produce two colonial variants has been disseminated to several Detroit-area hospitals. The clinical significance of the colonial morphotypes is unclear.

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins / genetics
  • Bacterial Typing Techniques
  • Carbon-Oxygen Ligases*
  • Drug Resistance, Microbial / genetics
  • Enterococcus faecium / classification
  • Enterococcus faecium / cytology*
  • Enterococcus faecium / drug effects*
  • Enterococcus faecium / genetics
  • Gram-Positive Bacterial Infections / microbiology*
  • Humans
  • Ligases / genetics
  • Michigan
  • Phenotype
  • Polymerase Chain Reaction
  • Vancomycin / pharmacology*

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • VanA ligase, Bacteria
  • Vancomycin
  • Ligases
  • Carbon-Oxygen Ligases