The clinical beginning of a Salmonella infection lies in
the initial contact of Salmonella to the epithelium of the
gastrointestinal system of the particular host, such as humans
or chickens. The bacteria that have made it this far
have had to overcome such hazards such as low pH in
the gastrointestinal system as well as any antimicrobial
or physical barriers or both. It is believed that the appendages
observed only when in contact with the epithelial
cells help mediate this survival, as they are no longer
observed after entry (Ginnochio et al., 1994).