R factors in group D streptococci: classification by compatibility.

Antibiotic transferable resistance determined by R-factors is largely distributed among the enterococci. Over a two year period, 106 strains of D streptococci have been tested. Transferable resistance has been detected in 45 strain (57.7% of the resistant strains). The compatibility group of 24 plasmids has been determined: 12 belong to the group I; 4 belong to the group II; only one to the group III; one belongs to compatibility group IV; k R-factors have attributed to a new group V and the other two are not classifiable in any of the described groups.