Enterobacter

Gram Stain: Small Gram-negative rods, found in clusters.

On Blood Agar: forms small to medium colonies, round in shape, mucod and opaque in colour, flat. On MacConkey Agar: Normal coloured agar, purplish colonies, small round, slightly raised, moist On XLD plates: Fermentative - yellow agar, large yellow-cream colonies, slightly raised, moist.

Catalase: positive, Oxidase: negative, Urea: negative, Indole: negative, MR: negative, VP: positive, Citrate: negative, Gas from Glucose: positive, Motile, TSI: A/A with gas production

Causes opportunistic infections in compromised (usually hospitalised) host. Urinary and Respiratory tract most common sites of infection.