[Incompatibility groups of resistance plasmids of Shigella sonnei]

The antibiotic resistance of 12 strains of Shigella sonnei isolated in Sicily was studied. All the strains were proved to carry autotransferable R plasmids belonging to 4 incompatibility groups: Inc I1, FI, FII and B-10-0. The variety of R plasmids identified gives evidence of the frequency of exchange of S. sonnei with other enterobacteria.