In vitro invasiveness and intracellular survival of Salmonella strains isolated from the aquatic environment

Salmonella has a life cycle between the host and the external environment where it is exposed to stressful conditions that may affect its virulence. In this study, we compared the capability of two aquatic (S. Oranienburg S76 and Saintpaul S70) and one clinical isolates (S. Oranienburg S347) to adhere and invade epithelial cells, and to survive within macrophages. S76 and S70, were less adherent to Caco‐2 cells than S347, but they were more invasive. The intracellular survival and growth of S76 in macrophages was increased with time, while S347 showed the highest peak value and S70 survived at moderate levels. Induced cell death in infected epithelial cells and macrophages revealed no differences between all strains. In conclusion, the contrasting responses detected between environmental and clinical isolates could indicate the importance of the distinct adaptation conditions of the strains to the isolation environment that could differentially affect their interaction with the host.