Abstract
The broad-host-range plasmid pAM.beta.1 (erythromycin resistance) was transferred conjugally from Streptococcus lactis to Lactobacillus reuteri, L. murinus, and L. fermentum. Transfer of pAM.beta.1 between two L. reuteri strains occurred, and lactobacillus transconjugants could act as donors of pAM.beta.1 in crosses with Enterococcus faecalis JH2-2.