First Isolation of Vancomycin-Resistant Enterococcus faecium Carrying Plasmid-Borne vanD1.

Vancomycin-resistant Enterococcus faecium carrying the vanD1 gene on plasmid pEF-D was isolated from a fecal sample of a hospitalized patient in Japan. The strain JH5687 showed moderate resistance to vancomycin (MIC, 16 μg/mL) but remained susceptible to teicoplanin (MIC, 1 μg/mL). The backbone gene organization of pEF-D was highly homologous to that of conjugative plasmid pMG1 or pHTβ. The calculated conjugation frequency of JH5687 was 10-4 to 10-5 per donor cell.