INTENDED USE
- Pre-poured agar medium on 90mm Petri dishes used for selective cultivation of Salmonella and Shigella from fecal samples.
PRINCIPLE
- TraceMedia™ Salmonella Shigella Agar is a selective medium in which Gram-positive bacteria are inhibited by bile salts.
- The high concentration of Citrate and Sodium thiosulfate limits the growth of Coliform bacteria and inhibits the growth of Proteus.
- Lactose fermentation produces acid, indicated by the formation of red colonies.
- Lactose-negative bacteria form colorless colonies.
- When thiosulfate and citrate are present in the medium, hydrogen sulfide-producing bacteria will form colonies with a black center.
RESULTS
- After incubation for the required time, typically 18-24 hours, observe the colonies’ growth on the plate with characteristic features of size, color, and morphology.
- Lactose non-fermenting species will appear as colorless colonies, while lactose fermenting species on the surface of the medium will appear as pink-red colonies.
- Most Salmonella and Shigella do not ferment lactose, resulting in colorless or pale colonies.
- Salmonella is often distinguished by the presence of black centers due to the reaction with H2S-indicator.
- Further identification of isolated bacteria must be conducted through appropriate tests.