Mannitol Salt Phenol Red Agar, also known as Chapman Agar, is formulated to selectively isolate staphylococci. The high concentration of sodium chloride (7.5%) inhibits the growth of most other bacteria. The medium differentiates Staphylococcus aureus from other staphylococci based on mannitol fermentation. When S. aureus ferments mannitol, acid is produced, causing the phenol red indicator to change from red-pink to yellow. Non-pathogenic staphylococci typically do not ferment mannitol and appear as small red colonies without a color change in the medium.
Advantages
- Complies with United States Pharmacopeia (USP) requirements for microbial limit testing.
- High salt content ensures strong selectivity for halophilic staphylococci.
- Dual-purpose medium: provides both selective isolation and differential identification in one step.
- Cost-efficient NutriSelect® Basic powdered formulation suitable for routine microbiology.
- Clear visual readout with distinct yellow zones for mannitol-positive pathogens.
Technical specifications
| Catalogue number |
63567 |
| Brand / Product line |
Sigma-Aldrich / NutriSelect® Basic |
| Standards |
According to USP |
| Form |
Powder |
| Final pH |
7.4 ± 0.2 (25 °C) |
| Composition (g/L) |
NaCl (75.0); D-Mannitol (10.0); Peptone (10.0); Agar (15.0); Meat extract (1.0); Phenol red (0.025) |
| Preparation |
111.0 g/L |
| Storage temperature |
2–25 °C (dehydrated powder) |
Available packaging options
| 63567-500G-F |
500 g plastic bottle |
