Molecular analysis of vancomycin-resistant Enterococcus faecalis from Michigan hospitals during a 10 year period.

We evaluated the molecular relatedness of 47 clinical isolates of vancomycin-resistant Enterococcus faecalis collected from 15 Michigan hospitals from 1991 to 2000. There were 17 PFGE strain types for the 47 isolates. Ten of 15 hospitals demonstrated interhospital, and three of 15 intrahospital, dissemination of some isolates. Forty-two isolates (89.4%) demonstrated vanB resistance. All vanA isolates comprised unique PFGE groups, suggesting transposon dissemination or the presence of a similar plasmid. The results of this study suggest inter- and intrahospital dissemination of strains of vancomycin-resistant E. faecalis during a 10 year period in Michigan.