NAC Agar Medium – Nalidixic Acid Cetrimide Agar for Pseudomonas aeruginosa Isolation, 250g

Nalidixic Acid Cetrimide Agar (NAC Agar) is a selective culture medium used for the isolation and cultivation of Pseudomonas aeruginosa. This formulation provides a nutrient-rich base with cetrimide to inhibit most other bacteria, while nalidixic acid enhances selectivity. It is widely applied in clinical microbiology, water testing, and pharmaceutical quality control.

Complete Formula (per liter):

• Peptone: 20.0 g

• Dipotassium Phosphate (K2HPO4): 0.3 g

• Magnesium Sulfate (MgSO4): 0.2 g

• Cetrimide (Cetyltrimethylammonium Bromide): 0.2 g

• Agar: 15.0 g

• Final pH: 7.4 ± 0.2 (25°C)

⚠ Note: The basal medium does not contain nalidixic acid. For full selectivity, add nalidixic acid solution before plating.

Preparation & Instructions:

1. Weigh 35.7 g of NAC Agar powder.

2. Suspend in 1 liter distilled or deionized water.

3. Heat to boiling until completely dissolved.

4. Dispense into containers and sterilize at 121°C for 15 minutes.

5. Cool to 50–55°C, then aseptically add nalidixic acid solution (1 vial per 100 ml medium).

6. Mix thoroughly, pour into Petri dishes, allow to solidify, and store for use.

Packaging & Storage:

• 250 g per bottle

• Shelf life: 3 years

• Storage: Keep tightly sealed in a cool, dry place at room temperature