Thermo Scientific™ Oxoid™ Peptone Water (Dehydrated), 500G

The Thermo Scientific™ Oxoid™ Peptone Water is a basal medium primarily used for carbohydrate fermentation studies and as a growth medium for various microorganisms. It is also a convenient medium for preparing inoculums for diagnostic media or fermentation tubes.

Key Features

1. Versatile Medium:
   • Serves as a growth medium or a base for carbohydrate fermentation tests.
   • Suitable for enriching Vibrio cholerae at an adjusted pH of 8.4.
2. Customizable for Fermentation Studies:
   • Carbohydrates and Andrade’s indicator can be added to perform fermentation tests.
3. Neutral pH:
   • Maintains a pH of 7.2 ± 0.2 for optimal microbial growth.
4. Compatibility:
   • Compatible with various sugars at a final concentration of 1% w/v for fermentation testing.

Composition

Directions for Preparation

1. Reconstitution:
   • Dissolve 15 g of Peptone Water in 1 litre of distilled water.
   • Mix well and distribute into final containers.
2. Sterilization:
   • Autoclave at 121°C for 15 minutes.
3. Modifications for Fermentation Tests:
   • Add Andrade’s indicator (prepared by adjusting acid fuchsin with sodium hydroxide until yellow) to Peptone Water.
   • Add sterile 10% sugar solutions post-autoclaving to achieve a final 1% w/v sugar concentration.

Applications

1. Fermentation Studies:
   • Detect carbohydrate utilization using sugars and Andrade’s indicator.
   • Includes options to detect gas production using inverted Durham tubes (for glucose).
2. Growth Medium:
   • Suitable for general-purpose microbial cultivation.
3. Inoculum Preparation:
   • Acts as a base medium for inoculum used in other diagnostic or fermentation tests.
4. Vibrio Enrichment:
   • Adjusting pH to 8.4 makes it ideal for Vibrio cholerae enrichment.

Storage and Stability

• Dehydrated Medium: Store at 10–30°C; use before the expiry date.
• Prepared Medium: Store at room temperature for routine use.

Appearance

Quality Control

• Positive Control: Escherichia coli ATCC® 25922, showing turbid growth.
• Negative Control: Uninoculated medium, showing no change.

Precautions

1. Andrade Indicator Handling:
   • Avoid inhalation or skin contact with acid fuchsin.
   • Monitor the indicator’s expiry as it fades over time.
2. Sub-culturing:
   • Perform sub-cultures to ensure the purity of inoculants.
3. Sugar Media Coding:
   • Clearly label each sugar bottle to avoid errors during fermentation tests.

Applications in Research and Clinical Settings

• Widely used in clinical microbiology labs for carbohydrate fermentation tests.
• Effective as a basal growth medium for routine culturing and microbial diagnostics.
• Supports fermentation studies to analyze carbohydrate metabolism in microbial species.

The Oxoid Peptone Water is an essential tool for laboratories focused on microbial diagnostics, growth, and metabolic studies.

References

1. Cruickshank R. (1968) Medical Microbiology, 11th Edition, Livingstone Ltd., London.