We cloned the vipR genes from Salmonella paratyphi C, S. dublin, and C
itrobacter freundii strains and compared them with the S. typhi sequen
ce to clarify the genetic relationship of the ViaB regions of Vi-posit
ive organisms. ViaB regions were divided into two groups based on thei
r sequences, the Salmonella and C. freundii groups. The vipR coding se
quences of the Salmonella group were identical. Southern blot hybridiz
ation results using the full-length ViaB region as a probe support the
se findings.