TY - JOUR
T1 - At least four percent of the Salmonella typhimurium genome is required for fatal infection of mice
AU - Bowe, Frances
AU - Lipps, Craig J.
AU - Tsolis, Renee M.
AU - Groisman, Eduardo
AU - Heffron, Fred
AU - Kusters, Johannes G.
PY - 1998/7
Y1 - 1998/7
N2 - Salmonella typhimurium infection of mice is an established model system for studying typhoid fever in humans. Using this model, we identified S. typhimurium genes which are absolutely required to cause fatal murine infection by testing independently derived transposon insertion mutants for loss of virulence in vivo. Of the 330 mutants tested intraperitoneally and the 197 mutants tested intragastrically, 12 mutants with 50% lethal doses greater than 1,000 times that of the parental Strain were identified. These attenuated mutants were characterized by in vitro assays which correlate with known virulence functions. In addition, the corresponding transposon insertions were mapped within the S. typhimurium genome and the nucleotide sequence of the transposon-flanking DNA was obtained. Salmonella spp. and related bacteria were probed with flanking DNA for the presence of these genes. All 12 attenuated mutants had insertions in known genes, although the attenuating effects of only two of these were previously described. Furthermore, the proportion of attenuated mutants obtained in this study suggests that mutations in about 4% of the Salmonella genome lead to 1,000- fold or greater attenuation in the mouse typhoid model of infection. Most of these genes appear to be required during the early stages of a natural infection.
AB - Salmonella typhimurium infection of mice is an established model system for studying typhoid fever in humans. Using this model, we identified S. typhimurium genes which are absolutely required to cause fatal murine infection by testing independently derived transposon insertion mutants for loss of virulence in vivo. Of the 330 mutants tested intraperitoneally and the 197 mutants tested intragastrically, 12 mutants with 50% lethal doses greater than 1,000 times that of the parental Strain were identified. These attenuated mutants were characterized by in vitro assays which correlate with known virulence functions. In addition, the corresponding transposon insertions were mapped within the S. typhimurium genome and the nucleotide sequence of the transposon-flanking DNA was obtained. Salmonella spp. and related bacteria were probed with flanking DNA for the presence of these genes. All 12 attenuated mutants had insertions in known genes, although the attenuating effects of only two of these were previously described. Furthermore, the proportion of attenuated mutants obtained in this study suggests that mutations in about 4% of the Salmonella genome lead to 1,000- fold or greater attenuation in the mouse typhoid model of infection. Most of these genes appear to be required during the early stages of a natural infection.
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U2 - 10.1128/iai.66.7.3372-3377.1998
DO - 10.1128/iai.66.7.3372-3377.1998
M3 - Article
C2 - 9632607
AN - SCOPUS:0031869632
SN - 0019-9567
VL - 66
SP - 3372
EP - 3377
JO - Infection and Immunity
JF - Infection and Immunity
IS - 7
ER -