Molecular characterization of a novel siderophore-independent iron transport system in Yersinia

Enteropathogenic Yersinia enterocolitica can be divided into mouse lethal ( biogroup 1 B serotypes O:8, O:13, O:20 and O:21) and mouse non-lethal (biog roups 2-4 serotypes O:3, O:5,27, O:9) strains. Mouse-lethality is associate d with the presence of the high-pathogenicity island encoding the TonB-depe ndent ferric-yersiniabactin uptake system. The present study reports on a T onB-independent and non-siderophore yersiniae ferric uptake system, yfu. Ge netic and functional characterization of the yfu determinant revealed high relationship to the periplasmic-binding-protein-dependent Serratia marcesce ns ferric uptake system sfu. The yfu locus is common to all Yersinia specie s pathogenic for humans. Gene targeting of the yfu locus has demonstrated i ts importance for ferric iron acquisition in vitro. However, yfu is not req uired for mouse virulence of Y. enterocolitica serotype O:8.