A galE via (Vi antigen-negative) mutant of Salmonella typhi Ty2 retains virulence in humans

DM Hone, SR Attridge, B Forrest, R Morona… - Infection and …, 1988 - Am Soc Microbiol
DM Hone, SR Attridge, B Forrest, R Morona, D Daniels, JT LaBrooy, RC Bartholomeusz…
Infection and immunity, 1988Am Soc Microbiol
We have recently described the construction of a galE derivative of Salmonella typhi Ty2
(Ty2H1) which had a 0.4-kilobase deletion in the galE gene and was sensitive to galactose-
induced lysis when cultured with greater than or equal to 0.06 mM galactose (DM Hone, R.
Morona, S. Attridge, and J. Hackett, J. Infect. Dis. 156: 167-174, 1987). We now report the
selection of a rifampin-resistant, via derivative of Ty2H1, EX462. Compared with the Ty2
parent strain, EX462 was serum sensitive and highly attenuated in the mouse mucin …
We have recently described the construction of a galE derivative of Salmonella typhi Ty2 (Ty2H1) which had a 0.4-kilobase deletion in the galE gene and was sensitive to galactose-induced lysis when cultured with greater than or equal to 0.06 mM galactose (D. M. Hone, R. Morona, S. Attridge, and J. Hackett, J. Infect. Dis. 156:167-174, 1987). We now report the selection of a rifampin-resistant, via derivative of Ty2H1, EX462. Compared with the Ty2 parent strain, EX462 was serum sensitive and highly attenuated in the mouse mucin virulence assay. When four human volunteers ingested 7 X 10(8) viable EX462, two became ill and developed a typhoidlike disease with fever and bacteremia. Blood isolates from these individuals were indistinguishable from the vaccine strain by a variety of criteria. We concluded that, even in a via background, the galE mutation was not attenuating for S. typhi in humans.
American Society for Microbiology