The Salmonella invasion strategy is fueled by the bacterium's ability to use type III secretion systems (T3SS). T3SSs are needle-like structures that allow Salmonella to inject effector proteins into host cells, which can manipulate the host cell's function and allow Salmonella to invade and survive within the cell.

The effector proteins injected by Salmonella T3SSs have various functions, including:

- Inhibiting the host cell's immune response

- Promoting the uptake of Salmonella into host cells

- Modifying the host cell's cytoskeleton to create a niche for Salmonella replication

- Inducing cell death to release Salmonella into the extracellular environment

These effector proteins work together to facilitate Salmonella's invasion and replication within host cells, allowing the bacterium to cause disease.