Unusual Yersinia enterocolitica isolates not associated with mesenteric lymphadenitis.

Thirteen Yersinia enterocolitica were recovered from a variety of clinical sources. Of these, only one was associated with mesenteric lymphadenitis and belonged to serotype 8. The 12 remaining strains were isolated from nonmesenteric sources and belonged to serotype 17. All strains exhibited the main characteristics of Y. enterocolitica which differentiated them from other Enterobacteriaceae, i.e., motility at 22 C but not at 37 C, positive urease and ornithine decarboxylase activities, and negative phenylalanine deaminase. These 12 strains differed, however, from other Y. enterocolitica previously described in the United States in that they fermented rhamnose and raffinose at 22 C, and failed to grow on Salmonella-Shigella and Hektoen-Enteric agars.