Genetic transformation of various species of Enterococcus by electroporation.

A transformation system for Enterococcus faecalis was developed which uses untreated (i.e., non-protoplasted) cells and the electroporation technique. The optimized protocol resulted in transformation efficiencies of up to 4 x 10(6) transformants per microgram of plasmid DNA. All strains of E. faecalis tested could be transformed by this method, albeit with differing transformation efficiencies. Using the protocol optimized for E. faecalis we successfully transformed Enterococcus faecium, E. hirae, E. malodoratus and E. mundtii.