Evaluation and characterization of multiresistant Enterococcus faecium from 12 U.S. medical centers

Forty-two Enterococcus faecium isolates resistant to ampicillin, penicillin, gentamicin, streptomycin, vancomycin, and teicoplanin (VanA phenotype) from 12 U.S. medical centers were analyzed by pulsed-field gel electrophoresis of chromosomal DNA. The isolates were tested for susceptibility to 12 alternative drugs. The results indicated both intrahospital and interhospital diversity among multiresistant vanA enterococcal isolates. Furthermore, the finding of isolates with identical pulsed-field gel electrophoresis patterns in different centers strongly suggests some interhospital clonal transmission.