Abstract
A total of 207 strains of Yersinia enterocolitica serotype O3, isolated from human, pig, dog, cat, rat and pork meat during the period between 1972 and 1984 were examined for the 44-megadalton plasmid DNA, calcium dependency and autoagglutination. Strains positive for the plasmid, calcium dependency and autoagglutination were counted and found to be 164 (792.%), 152 (73.4%) and 149 (72.0%), respectively. All the plasmid harboring strains were either calcium dependent or positive for the autoagglutination. All the strains which lacked the plasmid were calcium independent and negative for the autoagglutination except for strains (1.9%) that were positive for the autoagglutination. Despite different sources of Y. enterocolitica, all the plasmid positive strains harbored a single plasmid of 44-megadalton. These plasmids had identical restriction endonuclease digestion patterns, and the number of digestion fragments by BamHI, EcoRI and HindIII were 9, 10 and 13, respectively. Based on these results, it is suggested that the presence of the 44-megadalton plasmid in Y. enterocolitica serotype O3 strains is closely related to calcium dependency and autoagglutination and that this plasmid may be inherent to serotype O3.