Yersinia enterocolitica on Endo agar with biochemical slope. Cultivation 24 hours, 37°C.

Typical biochemical properties of Y.enterocolitica:

• lactose negative (but ONPG positive, presence of the inducible enzyme beta-galactosidase; Y.enterocolitica belongs to the group of so called "late lactose fermenters"; compare with the lactose-positive colonies of E.coli on Endo and delayed E.coli strains).
• sucrose fermentation (red coloured agar and colonies around the sucrose tablet)
• D-mannitol fermentation (red coloured agar and colonies around the mannitol tablet; a weak reaction in both strains)
• cellobiose fermentation (here negative but about 75% positive)
• acid from glucose without gas
• urea usually positive (bluish color of the biochemical slope; about 75% positive)
• hydrogen sulfide negative (compare with Salmonella enterica)