Yersinia Selective Agar 500g

Based on the work of Schiemann, this medium is used for the isolation and enumeration of Yersinia spp. from clinical samples and from food. The selective components are sodium desoxycholate, crystal violet, cefsulodin, irgasan and novobiocin. Yerseniae ferment mannitol with an intense, localised, acid production in the centre of the colony which produces a red ‹bull’s eye› appearance. The ratio of transparent border to red centre varies with serotype and environmental strains may appear rough with an irregular edge. Most other enteric bacteria, if they grow, produce a larger colony with a diffuse pinkish centre and opaque outer zone.