Inc groups among plasmids harbored by Escherichia coli of avian origin.

The enteric flora of poultry includes a high proportion of antibiotic-resistant Escherichia coli strains harboring conjugative plasmids: 54 of these strains were selected for their ability to transfer tetracycline resistance (associated or not with other resistances). Among the plasmids transferred from these strains, incompatibility tests revealed a high incidence of group Inc I1 and a low frequency of group Inc FII. The importance of group Inc P was confirmed. No Inc N plasmid was found. This pattern differs from what has been reported for human strains.