Table 2.

Differentiating reactions produced by the SSI enteric medium and possible identity of the pathogenic bacteria

ReactionPossible identity
H2SLactosePDaIndole
+ Salmonellaspp. (including Salmonella arizonae), lactose-negativeCitrobacter freundii, Shewanella putrefaciens
++ E. coli (of H2S-positive variety), Edwardsiella tarda
++ Citrobacter freundii, lactose-positiveSalmonella spp.
+++ E. coli (of H2S-positive variety)
++ Proteus mirabilis
+++ Proteus vulgaris
++ Morganella morganii,Providencia spp.
Shigellaspp., Yersinia spp., Salmonella paratyphi A
+ Shigella spp., Vibrio spp.,Aeromonas spp., E. coli, Plesiomonasspp.
+ Klebsiella pneumoniae,Enterobacter spp.
++ E. coli,Aeromonas spp., Klebsiella oxytoca
  • a Phenylalanine deaminase.