Arginine-Dependent Acid Resistance in Salmonella enterica Serovar Typhimurium

Abstract

Salmonella enterica serovar Typhimurium does not survive a pH 2.5 acid challenge under conditions similar to those used for Escherichia coli (J. W. Foster, Nat. Rev. Microbiol. 2:898-907, 2004). Here, we provide evidence that S. enterica serovar Typhimurium can display arginine-dependent acid resistance (AR) provided the cells are grown under anoxic conditions and not under the microaerobic conditions used for assessment of AR in E. coli . The role of the arginine decarboxylase pathway in Salmonella AR was shown by the loss of AR in mutants lacking adiA , which encodes arginine decarboxylase; adiC , which encodes the arginine-agmatine antiporter; or adiY , which encodes an AraC-like regulator. Transcription of adiA and adiC was found to be dependent on AdiY, anaerobiosis, and acidic pH.