Hybridization of Deoxyribonucleotide Sequences of Yersinia enterocolitica and Other Selected Members of Enterobacteriaceae 1

Using Yersinia enterocolitica Becht 18 as a standard reference, we obtained deoxyribonucleic acid base sequence homologies ranging from 79 to 100% for 11 additional isolates of the species representing 9 serotypes. These organisms, many of which exhibited dissimilar biochemical reactions, therefore belong to one and the same species. However, the degree of relatedness between Y. enterocolitica and the established members of the genus (Yersinia pestis and Yesinia pseudotuberculosis) was low (18 to 24%), approaching that obtained for some of 10 selected isolates of 7 other genera of Enterobacteriaceae (2 to 16%). These findings suggest that the proposal to include Y. enterocolitica within the genus Yersinia requires further evaluation.