Yersiniae other than Y-enterocolitica, Y-pseudotuberculosis, and Y-pestis:the ignored species

The genus Yersinia is composed of 11 species, of which three (TY: pestis, Y : pseudotuberculosis, and Y. enterocolitica) have been exhaustively charact erized. The remaining eight species (Y. frederiksenii, Y. intermedia, Y. kr istensenii, Y. bercovieri, Y. mollaretii, Y. rohdei, Y. ruckeri, and Y. ald ovde) have not been studied extensively and, because of the absence of clas sical Yersinia virulence markers, are generally considered to be nonpathoge nic. However, recent data suggest that some of these eight species may caus e disease by virtue of their having virulence factors distinct from those o f Y. enterocolitica. These data raise intriguing questions about the mechan isms by which these species interact with their host cells and elicit human disease. (C) 2000 Editions scientifiques et medicales Elsevier SAS.