TABLE 2.

Transfer frequency of plasmid pMG1 in Enterococcus^a

Donor	Recipient	Type of mating	Transfer frequency after 3 h of mating (no. of transconjugants per donor cell)
E. faecium KTSS(pMG1)	E. faecium KTRF	Intraspecies	6 × 10−4
E. faecium KTSS(pMG1)	E. faecalis FA2-2	Interspecies	2 × 10−4
E. faecalis FA2-2(pMG1)	E. faecalis JH2SS	Intraspecies	4.5 × 10−4
E. faecalis JH2SS(pMG1)	E. faecium KTRF	Interspecies	4 × 10−5
E. faecalis JH2SS(pAM714)	E. faecalis FA2-2	Intraspecies	2 × 10−2
E. faecalis JH2SS(pAM714)	E. faecium KTRF	Interspecies	<10−7

^aBroth matings were performed as described in Materials and Methods. Fresh N2GT broth and mixtures of donor and recipient strains were incubated at 37°C with gentle agitation for 3 h and then vortexed. Aliquots of the mixed culture were then plated on solid medium with appropriate antibiotics for selection. The selective medium was THB agar containing gentamicin or erythromycin for the selection of pMG1 or pAM714 transconjugants, respectively, plus the appropriate drugs for the selection of the recipient strains. The plates were incubated for 2 days at 37°C, and the colonies were counted.