This medium is based on the formulation by Moeller and contains L-Ornithine as the specific amino acid substrate. The medium includes glucose (dextrose) as a fermentable carbohydrate and the pH indicator bromocresol purple. During the initial hours of incubation, the organism ferments glucose, producing acid which turns the broth yellow. This acidic environment activates the ornithine decarboxylase enzyme. If the organism possesses this enzyme, it decarboxylates the L-Ornithine to form the alkaline diamine putrescine, which raises the pH and reverts the broth back to its original purple color. As part of the NutriSelect® Plus line, this medium provides high sensitivity and clear, reproducible biochemical reactions.
Advantages
- High Specificity: Pre-supplemented with L-Ornithine for convenient and accurate differentiation of species like Proteus mirabilis (positive) from Proteus vulgaris (negative).
- Easy Visualization: The bromocresol purple indicator provides a sharp, high-contrast color change from yellow to deep purple.
- NutriSelect® Plus Quality: Manufactured with premium-grade ingredients to ensure consistent growth and metabolic activity.
- Essential Identification Tool: Part of the core biochemical battery (along with Lysine and Arginine decarboxylation) for identifying enteric pathogens.
- Standardized Results: Follows established Moeller specifications for diagnostic microbiology.
Interpretation of Results
| Reaction |
Appearance |
Interpretation |
| Positive (+) |
Purple / Violet |
Ornithine decarboxylated (Alkaline) |
| Negative (-) |
Yellow |
Glucose fermentation only (Acidic) |
Technical specifications
| Catalogue number |
O5386 |
| Brand / Product Line |
Sigma-Aldrich / NutriSelect® Plus |
| Typical Composition (g/L) |
L-Ornithine hydrochloride (5.0); Peptic digest of animal tissue (5.0); Beef extract (5.0); Dextrose (0.5); Bromocresol purple (0.01); Cresol red (0.005); Pyridoxal (0.005) |
| pH (at 25 °C) |
6.0 ± 0.2 |
| Preparation |
19.52 g/L |
| Storage Temperature |
15 – 25 °C |
Available packaging options
| O5386-500G |
500 g plastic bottle |
