The fate of not sensing phosphate: downregulation of type 1 fimbriae through activation of the Pho regulon reduces E. coli urinary tract virulence.

Phosphate, in terms of cellular content, is the fifth most important element. Its homeostasis is controlled by the two-component system (TCS) PhoBR. The pstSCAB-phoU operon, encoding the phosphate specific transport system (Pst), is among the genes regulated by PhoBR. It mediates phosphate acquisition and is required for virulence in pathogenic bacteria. Recently, we demonstrated in uropathogenic Escherichia coli (UPEC) that inactivation of the Pst system negatively regulates expression of type 1 fimbriae and alters the ability to colonize the mouse urinary tract.