RESUMEN
BACKGROUND: Enterococci have emerged in recent years as a frequent cause of life-threatening nosocomial infections. The emergence of vancomycin-resistant enterococci(VRE) presents as an increasingly important problem particularly in the treatment and the potential dissemination of vancomycin-resistance. The purpose of this study is to determine the phenotypes and genotypes of VRE isolated from five hospitals and to study the genetic relatedness among them. METHODS: Antimicrobial susceptibility patterns and amplification of vancomycin resistance genes were used for phenotyping and genotyping of 42 VRE isolates respectively. For 21 isolates with vanA or vanB gene, plasmid profiles and pulsed field gel electrophoresis(PFGE) patterns were analyzed for molecular epidemiologic study. RESULTS: Out of 42 isolates, 21 were identified as E. faecium, 6 as E. faecalis, 2 as E. avium, and 13 as E. casseliflavus. Phenotyping showed 14 isolates as VanA(33%), 7 as VanB(17%) and 21 as VanC(50 %). Genotyping resulted in 12 isolates as vanA(5 of E. faecalis and 7 of E. faecium) and 9 as vanB(all E. faecium). Genotyping results were concordant with phenotyping results except for the two E. faecium isolates of VanA which had vanB genotype. Intrahospital spread of the same strains was proven in three hospitals by plasmid profiles and PFGE analysis. CONCLUSION: The study demonstrated a considerable number of VRE isolates in Korea and intrahospital spread proven by molecular epidemiologic methods. Although VRE infection has been considered very rare in Korea, practical guidelines including restriction of vancomycin usage and surveillance, are warranted to prevent infection and dissemination of VRE.