Thermo Scientific™ Oxoid™ Alkaline Peptone Water

The Thermo Scientific™ Oxoid™ Alkaline Peptone Water (CM1028) is a specialized enrichment medium designed for isolating Vibrio species, including Vibrio cholerae, from various sources such as food, water, and clinical samples. Here is a summary based on the provided details:

Key Characteristics:

• Primary Use: Non-selective enrichment of Vibrio spp., including Vibrio cholerae.
• Typical Formula:
  • Peptone: 10.0 g/l
  • Sodium Chloride: 20.0 g/l
  • pH: 8.6 ± 0.2 at 25°C
• Preparation Instructions: Dissolve 30 g of the medium in 1 liter of distilled water, mix thoroughly, distribute into containers, and sterilize at 121°C for 15 minutes.

Description and Functionality:

• The medium's alkalinity selectively promotes the growth of Vibrio species while suppressing unwanted flora.
• Sodium chloride (2%) supports the optimal growth of halophilic Vibrio species.
• Can be used for:
  • Direct enrichment from swabs, fecal samples, food, or water.
  • Microscopic examination using the hanging drop method.

Applications:

1. Clinical Samples:
   • Swab or 1g of fecal specimen inoculated directly.
   • Incubation:
     • 35-37°C for 5-6 hours or
     • 18-20°C for 18-20 hours.
2. Food and Water Samples:
   • Follow standards like APHA, FDA-BAM, or ISO methods.
   • Post-incubation, streak onto selective media such as:
     • TCBS Agar (CM0333)
     • MacConkey Agar (CM0007)

Observation and Biochemical Confirmation:

• Typical colony characteristics on plating media:
  • TCBS Agar: Yellow colonies (V. cholerae) or blue-green colonies (V. parahaemolyticus).
  • MacConkey Agar: Colorless colonies for lactose-negative Vibrio spp.
• Biochemical confirmation:
  • Oxidase-positive reaction.
  • Fermentation of glucose (acid production).

Storage and Shelf Life:

• Dehydrated Medium: Store at 10-30°C; ensure use before the expiry date.
• Prepared Medium: Store at room temperature for up to 1 month.

Quality Control:

• Positive Controls: Growth in the form of turbidity.
  • V. parahaemolyticus ATCC® 17802
  • V. vulnificus ATCC® 29307
  • V. furnissii ATCC® 11218
• Negative Control: No changes observed in uninoculated medium.

Appearance:

• Dehydrated Medium: Straw-colored, free-flowing powder.
• Prepared Medium: Clear, straw-colored liquid.

This medium is a valuable tool for microbiologists in the identification and enrichment of pathogenic Vibrio species, providing consistent and reliable results when used alongside standard testing protocols.

References:

1. Shread, P., Donovan T.J., and Lee J.V. (1991) Soc. Gen. Microbiol. Q. 8:184.
2. Cruickshank, R. (1968) Medical Microbiology. 11th ed. Livingstone Ltd, London, UK.
3. Janda J.M., et al. (1988) Current Perspectives on the Epidemiology and Pathogenesis of Clinically Significant Vibrio spp. Clinical Microbiology Reviews July 3:245-267.
4. Standard Methods for the Examination of Water and Waste Water 20th Edition 1998 APHA.
5. Compendium of Methods for the Microbiological Examination of Foods, Fourth Edition 2001, APHA.
6. FDA BAM on line 2001 FDA BAM.
7. Methods for Microbiological Examination of Food and Animal Feeding Stuffs Part 14 Detection of Vibrio parahaemolyticus. BS5763: Part 14:1991 ISO 89.