Recombinant plasmid obtained from two different, compatible staphylococcal plasmids.

From two different, compatible staphylococcal plasmids that determine streptomycin and chloramphenicol resistance, respectively, a recombinant plasmid was obtained. This plasmid can be transduced with a rather high frequency (10(-4)/plaque-forming unit) to plasmid-negative strains, the linkage of the two markers being 100%. The maintenance of the recombinant plasmid in the host cell seems to be controlled by the chloramphenicol resistance plasmid. The recombinant plasmid proved to be incompatible with both parental plasmids, which are unrelated. The relationship between the chloramphenicol resistance plasmid and the recombinant plasmid was the same as the between genetically marked derivatives of the recombinant plasmid, whereas the relationship of the streptomycin resistance plasmid to the recombinant plasmid was of a different, asymmetrical type.