Effect of river water exposition on pathogenic abilities of Salmonella

What is it about?

This study was performed to evaluate in vitro the adherence and invasiveness capacity of Salmonella Oranienburg and Saintpaul (isolated from river water) exposed to laboratory and river water growth conditions and inoculated into epithelial HEp-2 cell. Results showed that Salmonella Oranienburg and Salmonella Saintpaul showed lower ability to adhere and invade epithelial HEp-2 cells under both growth conditions as compared to Salmonella Typhimurium reference strain. S. Oranienburg adhesion capacity was not affected by the growth conditions, while S. Saintpaul exposed to river water significantly (p < 0.05) decreased its adhesion capacity by 75.7 %. On the contrary, S. Oranienburg exposed to river water reduced its invasion efficiency by 80 %, whereas S. Saintpaul showed no differences between growth conditions. In conclusion, this study suggests that the exposure to non-host conditions, such as river water, adversely affects the adhesion and invasiveness of Salmonella serotypes differently, impacting on their ability to re-enter a new host.

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Why is it important?

In Mexico, both serotypes have been isolated from various environmental sources, including soil, farm and zoo animal feces, sewage effluent, and surface water (Jimenez et al. 2011; Silva-Hidalgo et al. 2012; Estrada-Acosta et al. 2014; Jimenez et al. 2014). When compared to other Salmonella serotypes, S. Oranienburg and Saintpaul may become relevant due to its ability to remain viable in the environment and be long-term persistent (Martinez-Urtaza and Liebana 2005). This behavior must be associated to the continuous effort of colonizing new hosts (Winfield and Groisman 2003; Simental and Martinez-Urtaza 2008; Haley et al. 2009), implying changes in gene expression, dealing with modifications in the bacterial pathogenic capacity, as well as structural changes for better performance when facing new ecosystems (Reen et al. 2005).

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