Transcriptome sequencing reveals genes and adaptation pathways in Salmonella Typhimurium inoculated in four low water activity foods

Salmonella enterica serotypes have been reported as the agent of various outbreaks occurred after the consumption of low water activity (aw) foods. When the pathogen encounters harsh conditions, several regulatory networks are activated through genetic modifications that lead to cell survival for prolonged periods. In this work, the transcriptome of S. enterica serovar Typhimurium using RNA-Seq, after cells' inoculation in four distinct types of low aw foods (milk chocolate, powdered milk, black pepper and dried pet food), following storage at 25°C per 24 and 72h was studied. The findings of this study suggest that the food composition influences gene regulation mainly in the first hour post-inoculum, proceeded by the induction of similar genes shared among all samples. It was possible to evaluate the differences on each type of food matrix regarding the bacteria adaptation, as well as the similarities provoked by low aw. The results reveal genes that may play key roles in the response to desiccation in Salmonella, as well as the pathways in which they are involved.