Yersinia frederiksenii: A new species of enterobacteriaceae composed of rhamnose-positive strains (formerly called atypical yersinia enterocolitica or Yersinia enterocolitica-Like)

Yersinia frederiksenii sp. nov. is defined biochemically and genetically. Y. frederiksenii stains belong to three separate DNA relatedness groups, each of which is separable from Y. enterocolitica, Y. intermedia, Y. kristensenii, Y. pseudotuberculosis, and Yersinia biotypes X1 and X2. The three Y. frederiksenii DNA relatedness groups, 6175, 2581-77, and 867, were represected by 10, 3, and 1 strain, respectively. All three groups were phenotypically similar. Pending additional study, it was decided to retain them all in Y. frederiksenii. The positive rhamnose reaction separates Y. frederiksenii from Y. enterocolitica, Y. kristensenii, and Yersinia biotype X1. A positive sucrose reaction distinguishes Y. frederiksenii from the rhamnose-positive, sucrose-negative Yersinia biotype X2. Negative reactions for melibiose, raffinose, and α-methyl-d-glucoside distinguish Y. frederiksenii from Y. intermedia. A negative melibiose reaction and positive reactions for ornithine decarboxylase, indole, sucrose, sorbose, sorbitol, inositol, and Voges-Proskauer separate Y. frederiksenii from Y. pseudotuberculosis. Strain 6175 (=CIP 80-29) is proposed as the type strain for Y. frederiksenii.