TY - JOUR
T1 - Intracellular replication is essential for the virulence of Salmonella typhimurium
AU - Leung, K. Y.
AU - Finlay, B. B.
PY - 1991
Y1 - 1991
N2 - Salmonella typhimurium is a facultative intracellular parasite, capable of penetrating, surviving, and multiplying within diverse eukaryotic cell types, including epithelial and phagocytic cells. We have been studying intracellular replication of S. typhimurium and found that it is essential in the pathogenesis of this bacterium. A total of 45,000 independent mini-Mu MudJ transposon mutants in S. typhimurium SL1344 were screened in Madin-Darby canine kidney (MDCK) epithelial cells with a β-lactam, cefotaxime, to enrich for mutants defective for intracellular replication. Ten different auxotrophic (purine, pyrimidine, purine/methionine, and valine/isoleucine) and three prototrophic replication-defective mutants (Rep-) were identified. AH Rep- mutants showed no differences in aerobic and anaerobic growth patterns, motility, serum sensitivity, mouse macrophage survival, iron uptake, and phosphate requirements. All Rep- mutants were unable to multiply inside MDCK, HeLa, and Caco-2 epithelial cells. When required nutrients for various auxotrophs were supplemented, auxotrophs then replicated inside MDCK cells. Although the parental strain multiplies in large vacuoles inside MDCK cells that distort the host cells, MDCK cells infected with the Rep mutants appeared relatively normal and few bacteria were seen inside vacuoles. The purine auxotrophs and the three prototrophic Rep mutants were highly attenuated in mice, and oral and intraperitoneal LD50 levels were 3 to 4 orders of magnitude higher than the wild type level. The three prototrophs were invasive and persisted in the murine organs such as livers and spleens for at least 3 weeks. Therefore, these prototrophic genes are needed for intracellular replication and are essential to the virulence of S. typhimurium.
AB - Salmonella typhimurium is a facultative intracellular parasite, capable of penetrating, surviving, and multiplying within diverse eukaryotic cell types, including epithelial and phagocytic cells. We have been studying intracellular replication of S. typhimurium and found that it is essential in the pathogenesis of this bacterium. A total of 45,000 independent mini-Mu MudJ transposon mutants in S. typhimurium SL1344 were screened in Madin-Darby canine kidney (MDCK) epithelial cells with a β-lactam, cefotaxime, to enrich for mutants defective for intracellular replication. Ten different auxotrophic (purine, pyrimidine, purine/methionine, and valine/isoleucine) and three prototrophic replication-defective mutants (Rep-) were identified. AH Rep- mutants showed no differences in aerobic and anaerobic growth patterns, motility, serum sensitivity, mouse macrophage survival, iron uptake, and phosphate requirements. All Rep- mutants were unable to multiply inside MDCK, HeLa, and Caco-2 epithelial cells. When required nutrients for various auxotrophs were supplemented, auxotrophs then replicated inside MDCK cells. Although the parental strain multiplies in large vacuoles inside MDCK cells that distort the host cells, MDCK cells infected with the Rep mutants appeared relatively normal and few bacteria were seen inside vacuoles. The purine auxotrophs and the three prototrophic Rep mutants were highly attenuated in mice, and oral and intraperitoneal LD50 levels were 3 to 4 orders of magnitude higher than the wild type level. The three prototrophs were invasive and persisted in the murine organs such as livers and spleens for at least 3 weeks. Therefore, these prototrophic genes are needed for intracellular replication and are essential to the virulence of S. typhimurium.
KW - Intracellular parasite
KW - Pathogenesis
UR - http://www.scopus.com/inward/record.url?scp=0026345034&partnerID=8YFLogxK
U2 - 10.1073/pnas.88.24.11470
DO - 10.1073/pnas.88.24.11470
M3 - 文章
C2 - 1763061
AN - SCOPUS:0026345034
SN - 0027-8424
VL - 88
SP - 11470
EP - 11474
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 24
ER -