Conjugal transfer of the vancomycin resistance determinant vanB between enterococci involves the movement of large genetic elements from chromosome to chromosome.

Resistance to various levels of vancomycin and susceptibility to teicoplanin in enterococci (VanB phenotype) is mediated by the vanB gene cluster. VanB-type resistance was transferred by intra- and inter-specific conjugation between different strains of Enterococcus. Analysis of SfiI-digested genomic DNA by zero integrated-field electrophoresis followed by Southern hybridization revealed vanB-containing chromosomal insertions of approximately 90-250 kb in the transconjugants. Thus, transfer of VanB-type resistance is associated with the movement of large genetic elements from chromosome to chromosome.