Product No.	Product Category	Specification
HCM046	Dehydrated Culture Medium	500g/bottle

Intended Use

For the detection of coagulase-positive and mannitol-utilizing Staphylococci.

Principle and Interpretation

Pancreatic digest of casein provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group. Dipotassium hydrogen phosphate provides buffering to the medium. During the first 24 hours, contaminating organisms are almost inhibited by tellurite, lithium chloride and high glycine content. The effect of inhibitors on S.aureus is reduced because of the presence of mannitol and glycine. Coagulase-positive staphylococci reduce potassium tellurite to metallic free tellurium and thus produce black colonies surrounded by yellow zones. This yellow color is due to phenol red indicator that turns yellow in acidic condition due to mannitol fermentation. If mannitol is not fermented, yellow zones are not formed. Also, the color of the medium around the colonies may even be a deeper red than normal due to utilization of the peptones in the medium. Prolonged incubation may result in growth of black coagulase-negative colonies.

Formulation

Ingredients	/liter
Pancreatic digest of casein	10.0g
Yeast extract	5.0g
D-Mannitol	10.0g
Dipotassium hydrogen phosphate	5.0g
Lithium chloride	5.0g
L-Glycine	10.0g
Agar	16.0g
Phenol red	25.0mg
pH7.1±0.2 at 25°C

Preparation

Suspend 61g in 1L of distilled water , stirring heated to boiling to completely dissolve ,autoclave at 121℃ for 15 minutes.Cool to 50℃and add 20 mL of sterile 1% potassium tellurite . Do not heat the complete medium.

Quality Control

Cultural characteristics observed after incubation at 35-37°C for 24 -48hours

Quality control strains	Expected Results	Colony Color
Staphylococcus aureus subsp. Aureus ATCC6538	Good	black with yellow halo
Staphylococcus epidermidis CMCC(B)26069	Good	translucent to blackish
Proteus mirabilis CMCC(B)49005	Good	black
Escherichia coli ATCC25922	–	–

Storage and Shelf Life

2-30℃，Keep container tightly closed, avoid direct sunlight.

Use before expiry date on the label.

 Precautions

1. When weighing the dehydrated medium, please wear masks to avoid causing respiratory system discomfort

2. Keep container tightly closed after using to prevent clumping.

Waste Disposal

Microbiological contamination was disposed by autoclaving at 121°C for 30 minutes.

Revision

On June 14, 2024

References

United States Pharmacopeia, 2019.

FDA Bacteriological Analytical Manual, 2016, AOAC,