ABSTRACT
The genus Yersinia-a member of family Enterobacteriaceae of the γ-purple bacteria1-now comprises 14 species, three of which contain human pathogenic strains: Y. pestis, Y. pseudotuberculosis, and Y. enterocolitica. Y. pestis is the causative agent of the feared bubonic plague that spreads from infected rodents to humans via a ³ea vector.2 Pathogenic strains of Y. pseudotuberculosis and Y. enterocolitica cause yersiniosis, usually a mild diarrheal disease, the infection of which usually takes place by ingestion of contaminated foodstuffs. Y. pseudotuberculosis and Y. enterocolitica and related species (Y. aldovae, Y. aleksiciae, Y. bercovieri, Y. frederiksenii, Y. intermedia, Y. kristensenii, Y. mollaretii, Y. rohdei, Y. massiliensis, and Y. similis, the two latter of which were only recently described3,4) have several serovariants, whereas Y. pestis has three biovariants but is serologically of a single type. Five serotypes have been described for Y. ruckeri that causes the enteric red mouth disease of Šsh.5
