RPF Agar Medium Base – For Detection of Coagulase-Positive Staphylococcus (250g)

RPF Agar Medium Base is a specialized culture medium used for the detection of coagulase-positive staphylococci, particularly Staphylococcus aureus. This medium is formulated with essential nutrients and selective agents, and requires supplementation with potassium tellurite, rabbit plasma, bovine fibrinogen, and trypsin inhibitor for accurate detection.

It is widely applied in:

• Clinical microbiology laboratories

• Food safety and hygiene testing

• Public health monitoring

• Research in staphylococcal pathogenicity

The combination of fibrinogen, plasma, and inhibitors enables sensitive differentiation of coagulase-positive strains through clot formation and selective growth.

Composition (per liter):

• Tryptone – 10.0 g

• Beef Extract – 5.0 g

• Yeast Extract – 1.0 g

• Sodium Pyruvate – 10.0 g

• Glycine – 12.0 g

• Lithium Chloride – 5.0 g

• Agar – 15.0 g

• Final pH: 7.2 ± 0.2 (at 25°C)

Preparation & Instructions:

1. Suspend 58 g of powder in 900 ml distilled water.

2. Heat to boiling until completely dissolved.

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

4. Mix well after sterilization to prevent agar settling.

5. Cool in a water bath to 48°C.

6. Under aseptic conditions, add to each 90 ml medium:

   • 2.5 mg sterile potassium tellurite solution (2.5 mg per ampoule)

   • 2.5 ml rabbit plasma (fresh or lyophilized)

   • 7.5 ml bovine fibrinogen solution (5 g/100 ml, sterilized by 0.22 μm filtration)

   • 2.5 ml trypsin inhibitor solution (30 mg/30 ml, sterilized by 0.22 μm filtration)

7. Mix gently and pour into sterile Petri dishes.