Competition for resources:
Microbes within the microbiome compete with Salmonella for essential nutrients, such as iron, sugars, and amino acids. By consuming these resources, beneficial bacteria limit the growth and survival of Salmonella.
Production of antimicrobial substances:
Some beneficial bacteria produce antimicrobial compounds that can directly kill or inhibit the growth of Salmonella. For example, certain Lactobacillus strains produce lactic acid and hydrogen peroxide, which have antimicrobial effects against Salmonella.
Physical barriers:
Certain beneficial bacteria can form biofilms, which are complex communities of microbes that adhere to surfaces within the gut. These biofilms act as physical barriers that prevent Salmonella from colonizing and establishing infection.
Immune system stimulation:
Some members of the microbiome interact with immune cells in the gut and stimulate the immune response. This can lead to the activation of immune cells, such as macrophages and neutrophils, which can recognize and eliminate Salmonella.
Short-chain fatty acid production:
Beneficial bacteria can ferment dietary fibers and produce short-chain fatty acids (SCFAs) as by-products. SCFAs, such as butyrate, propionate, and acetate, have various beneficial effects on gut health, including the inhibition of Salmonella growth and the enhancement of the intestinal barrier function.
Mucus layer modulation:
The mucus layer lining the intestinal epithelium plays a crucial role in protecting against infections. Certain beneficial bacteria help maintain the integrity and thickness of the mucus layer, making it more difficult for Salmonella to penetrate and establish infection.
Quorum sensing inhibition:
Microbes communicate with each other through chemical signals called quorum sensing molecules. Some beneficial bacteria can interfere with this communication, disrupting the coordinated behavior of Salmonella and reducing its virulence.
By employing these diverse mechanisms, beneficial members of the microbiome contribute to the overall resistance of the host against Salmonella infections.
