The Acid Tolerance Response of Salmonella spp.: An adaptive strategy to survive in stressful environments prevailing in foods and the host

One of the best studied Salmonella spp. adaptive responses is the Acid Tolerance Response (ATR), responsible for bacterial survival under extreme acid conditions, and well characterized for Salmonella enterica serovar Typhimurium. This review covers the numerous studies carried out in the last two decades describing the influence of different environmental parameters on the S. Typhimurium ATR, including the complex molecular mechanisms implicated and involvement of the ATR in virulence. The review also deals with the food safety implications of this adaptive response. Finally, the limited data available regarding the ATR of other Salmonella enterica serovars is also discussed.

Research highlights
► The ATR is an adaptive response involved in survival under extreme acid niches.
► It is unknown whether the components of ATR systems are conserved in all serovars.
► pH homeostasis, synthesis of ASPs and membrane modulation are responsible for ATR.
► In vivo studies assessing the ATR determinants in foods and the host are required.