Conjugal plasmids in group D streptococci.

159 strains of group D streptococci isolated from clinical specimens were examinated for plasmids content. Our objective was to study some characters carried by plasmids: drug-resistance, hemolysins and bacteriocin activity. 73,6% of the strains were antibiotic resistant and in 69% of these, the drug-resistance was transferable by conjugation. In mating of S. faecalis subsp. zymogenes strains we could also isolate three different types of transconjugants in hemolytic activity. The interpretation of this observation was facilitated by the research of bacteriocin activity. We also classified the bacteriocins found in our strains into different types.