Incompatibility reactions of R plasmids isolated from Escherichia coli of animal origin

Abstract

The incompatibility reactions of a group of 90 R plasmids, isolated from the fecal Escherichia coli of calves, pigs and chickens, have been determined against reference plasmids of the incompatability groups F(II), groups F11, I, N, P, and W. Twenty plasmids belonged to incompatibility groups F(II), I, N, or P. Forty nine plasmids were compatible with all of the 5 reference plasmids. Eight plasmids exhibited marked incompatibility with representatives of 2 or more of the above groups, whereas 2 strains, showed incompatibility reactions consistent with the coexistence of 2 compatible plasmids. In addition, 19 plasmids remain untyped because they showed intermediate reactions with one or more reference plasmids.