Conjugative transfer of the transposon Tn919to lactic acid bacteria

The streptococcal transposon Tn919 was transferred from Streptococcus faecalis GF590 to selected Group N Streptococcus strains and to one strain each of Lactobacillus plantarum and Leuconostoc cremoris, using the filter mating method. An S. lactis MG1363 Rifr Tcr transconjugant also acted as a donor, but was less efficient than GF590. Frequencies of transfer varied between 4.0 × 10−8 and 5.29 × 10−5 per recipient. Further analysis of S. lactis MG1363 Smr Tcr transconjugants showed that insertion of Tn919 into the chromosome was site-specific.