Molecular epidemiology of Yersinia enterocolitica O:3 infections: use of chromosomal DNA restriction fragment length polymorphisms of rRNA genes.

ABSTRACT

Yersinia enterocolitica is a major enteric pathogen associated with a wide variety of clinical and immunologic manifestations, including transfusion-associated disease, from which there is a high mortality. Although previously rare in the United States, in the late 1980s Y. enterocolitica O3 emerged as the predominant serotype in the United States, as it has been in Canada, Europe, and Japan. Epidemiologic investigation of this serogroup has been hampered by the limited availability of a phage typing system and the fact that Y. enterocolitica harbors few plasmids that are useful as strain markers. We therefore analyzed whole-cell DNA restriction fragment length polymorphisms of rRNA genes (ribotyping) to study a group of 61 (50 human, 11 porcine) Y. enterocolitica isolates. Initially, 20 different restriction enzymes were used NciI appeared to give the best discrimination of hybridization banding patterns (ribotypes) within Y. enterocolitica O3. Ribotyping distinguished seven clones among all the study isolates and four clones within Y. enterocolitica O3 (53 isolates studied) and clearly differentiated Y. enterocolitica O3 from Y. enterocolitica O9; O1,2,3; O20; and O5,27. Most serogroup O3 isolates belonged to two clones, ribotypes I and II, including 23 of 24 Y. enterocolitica O3 (13 human, 11 porcine chitterling) isolates recovered from a recent outbreak of Y. enterocolitica in children in Atlanta associated with chitterling preparation and 3 transfusion-associated O3 isolates from the United States. Y. enterocolitica O3 ribotypes I and II were also isolated in Japan, ribotypes II and IV were isolated in Belgium, and ribotype I was isolated in Canada. Ribotype patterns I and II corresponded to phage types 9b and 8, respectively. Ribotyping was able to distinguish individual strains of Y. enterocolitica O3, but suggests that a limited number of clones have disseminated within the United States and globally. The finding of identical ribotype patterns in chitterling and human specimens from the Atlanta outbreak supports epidemiologic evidence that swine were the source of infection and major reservoir for Y. enterocolitica O3.