Open AccessThe live oral typhoid vaccine Ty21a is a rpoS mutant and is susceptible to various environmental stresses
Author(s) -
Robbesaule Véronique,
Coynault Colette,
Norel Françoise
Publication year - 1995
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1995.tb07412.x
Subject(s) - rpos , typhoid fever , typhoid vaccine , microbiology and biotechnology , mutant , virology , attenuated vaccine , biology , genetics , virulence , gene , gene expression , promoter
The rpoS (katF) gene, which encodes a RNA polymerase σ factor ( σ s ), regulates the virulence of Salmonella typhimurium in mice. In the present study, we show that rpoS mutants can be frequently found among laboratory strains of Salmonella . In addition, a rpoS mutation was identified in the S. typhi live oral vaccine Ty21a. Introduction of a wild‐type rpoS gene in Ty21a allowed the bacteria to survive better under starvation conditions and increased their resistance to other stresses. These results contribute to a better understanding of the genetic background of the live typhoid oral vaccine Ty21a and suggest that the rpoS mutation may contribute to the safety of this strain in humans.