Simmons Citrate Agar

Simmons Citrate Agar is a specialized microbiological medium essential for the differentiation of gram-negative bacteria based on their ability to utilize citrate as a sole carbon source. This high-quality medium is designed to meet the rigorous demands of both clinical and research laboratories, ensuring accurate identification and metabolic studies of various bacterial species.

Key Features:

• Citrate Utilization Testing: Specifically formulated for identifying gram-negative bacteria that can utilize ammonium dihydrogen phosphate and sodium citrate, critical for microbiological diagnostics.
• Color Change Indicator: The medium contains bromothymol blue, a pH indicator that shifts from green (neutral) to blue (alkaline) when citrate is metabolized, allowing for clear interpretation of results.
• High Purity Ingredients: Includes sodium chloride, magnesium sulfate, and agar, providing a stable environment for robust bacterial growth.

Formulation:

The approximate formula for Simmons Citrate Agar includes:

• Sodium Chloride: 5.0 g/liter
• Magnesium Sulfate: 0.2 g/liter
• Ammonium Dihydrogen Phosphate: 1.0 g/liter
• Dipotassium Hydrogen Phosphate: 1.0 g/liter
• Sodium Citrate: 5.0 g/liter
• Bromothymol Blue: 0.08 g/liter
• Agar: 15.0 g/liter
• Final pH: 6.8±0.2 at 25℃

Preparation:

To prepare Simmons Citrate Agar, suspend 27.3 g of the medium in one liter of deionized or distilled water. Mix thoroughly, heat with agitation, and boil for 1 minute. Dispense into tubes and sterilize in an autoclave at 121℃ (15 lbs.) for 15 minutes.

Applications:

• Bacterial Identification: Ideal for distinguishing citrate-positive gram-negative organisms in clinical diagnostics and environmental microbiology.
• Research Purposes: Supports studies in microbial metabolism, ecology, and environmental monitoring.

Appearance:

The dehydrated medium appears as a free-flowing light yellow-green powder, while the prepared medium forms a green transparent gel, providing a visually appealing and functional medium for bacterial culture.

Storage & Shelf Life:

Store Simmons Citrate Agar tightly capped at 5-30°C. The dehydrated medium has a shelf life of 3 years from the date of manufacture, while prepared medium should be stored at 2-8°C, protected from direct light, to maintain its integrity and effectiveness.

Quality Control:

Conduct quality control by incubating the medium at 36±1℃ for 24-48 hours, observing cultural characteristics for accurate results.

Precautions:

This medium is intended for laboratory use only. Do not use dried medium that is past its shelf life or exhibits caking or color variation.