Inherent Variability of Growth Media Impacts the Ability of Salmonella Typhimurium to Interact with Host Cells.
Efficient invasion of non-phagocytic cells, such as intestinal epithelial cells, by Salmonella Typhimurium is dependent on the Salmonella Pathogenicity Island 1 (SPI-1)-encoded Type Three Secretion System. The environmental cues involved in SPI-1 induction are not well understood. In vitro, various conditions are used to induce SPI-1 and the invasive phenotype. Although lysogeny broth (LB) is widely used, multiple formulations exist, and variation can arise due to intrinsic differences in complex components. Minimal media are also susceptible to variation. Still, the impact of these inconsistencies on Salmonella virulence gene expression has not been well studied. The goal of this project is to identify growth conditions in LB and minimal medium that affect SPI-1 induction in vitro using both whole population and single cell analysis. Here we show, using a fluorescent reporter of the SPI-1 gene prgH, that growth of Salmonella in LB yields variable induction. Deliberate modification of media components can influence the invasive profile. Finally, we demonstrate that changes in SPI-1 inducing conditions can affect the ability of Salmonella to replicate intracellularly. These data indicate that the specific media growth conditions impact how the bacteria interact with host cells.
Laboratory of Bacteriology, Rocky Mountain Labs, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America.
Sushmita
S
Sridhar
Laboratory of Bacteriology, Rocky Mountain Labs, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America.
Olivia
O
Steele-Mortimer
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D003470:Culture Media / Q000494:pharmacology*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D044404:Genomic Islands / Q000187:drug effects*; D006367:HeLa Cells; D006801:Humans; D012480:Salmonella Infections / Q000235:genetics / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000254:growth & development / Q000472:pathogenicity*; D014779:Virus Replication / Q000187:drug effects*
D001426:Bacterial Proteins; D003470:Culture Media; C419942:Spi1 protein, Salmonella