Many of the genes (pags (phoPactivatedgenes) andprgs (phoPrepressedgenes)) regulated
by the PhoP and PhoQ proteins (PhoP/Q) are necessary for survival ofSalmonella
typhimuriumin murine macrophages and pathogenesis in mice. Although a great deal is
known about theS. typhimuriumphoP/Qregulon, little has been done with the human specific
pathogenS. typhi, prompting us to investigateS. typhiphoP/Qregulated genes.
IsogenicphoP12 (null) andphoP24 (constitutive) strains were constructed inS. typhiTy2 …