Salmonella enterotoxin (stn) gene is prevalent among strains of Salmonella enterica, but not among Salmonella bongori and other Enterobacteriaceae.

All strains and serovars of Salmonella enterica such as serovar Typhimurium, Enteritidis, Dublin, Typhi, etc. were found to carry the Salmonella enterotoxin determinant stn as far as examined in PCR and hybridization studies. However, using MDCK cells for testing the toxicity of the strains under investigation, only a limited number of stn positive strains revealed phenotypically the Salmonella enterotoxin Stn. In contrast to S. enterica, other Enterobacteriaceae including Salmonella bongori were found neither genotypically nor phenotypically Stn toxin positive.