Salmonella enterica is a gastrointestinal pathogen whereas most strains of Escherichia coli and Klebsiella are generally non-pathogenic, yet all three may found in one sample. On the basis of the MR/VP and SIM results, is it possible to differentiate Salmonella from Escherichia or Klebsiella? If so, which test(s) would be most useful for this purpose.