[Instability of group FII plasmids in "Salmonella panama" (author's transl)].

Almost all Salmonella panama isolated in France only harbour R plasmids of incompatibility groups I1 (K Col Ib) and N (T). Reference R plasmids belonging to 11 incompatibility groups have been introduced into S. panama. All are stable after 50 generations except those of group FII. FII instability cannot be explained either by the presence of a group FII cryptic plasmid or by restriction enzymes in S. panama.