Liofilchem® Anaerobic agar (Brewer)

The Liofilchem® Anaerobic Agar (Brewer) is a solid, nonselective culture medium designed for the cultivation of both facultative and strict anaerobic bacteria, with a particular focus on Clostridium species. Based on a formula originally developed by Brewer, this medium is ideal for clinical and microbiological applications requiring the growth and isolation of anaerobic and microaerophilic organisms.

Key Features

1. Nonselective Growth Medium:
   • Supports the cultivation of a broad range of anaerobic and facultative anaerobic bacteria.
   • Optimized for the growth of Clostridium and other anaerobic species.
2. Brewer's Formula:
   • Incorporates sodium thioglycollate and sodium formaldehyde sulfoxylate as reducing agents to maintain an anaerobic environment.
3. Resazurin Indicator:
   • Includes a redox indicator (resazurin) that changes color in the presence of oxygen, signaling anaerobic or aerobic conditions.
4. Adaptability:
   • Can be used with a Brewer’s lid for surface cultivation of anaerobes and microaerophiles without requiring an anaerobic jar or pouch.

Typical Formula (per Liter)

The formula may be adjusted or supplemented to meet performance requirements.

Method Principle

• Nutritional Components:
  • Peptones and yeast extract provide amino acids, nitrogen, carbon, vitamins (especially B vitamins), and minerals for bacterial growth.
  • Glucose acts as a fermentable carbohydrate source.
• Reducing Agents:
  • Sodium thioglycollate and sodium formaldehyde sulfoxylate maintain an anaerobic atmosphere by reducing oxygen.
• Redox Indicator:
  • Resazurin indicates oxygen presence; a color change signals aerobic contamination.
• Agar:
  • Solidifies the medium, creating a stable platform for bacterial growth.

Preparation

1. Dehydrated Medium:
   • Suspend 58 g of powder in 1 liter of distilled or deionized water.
   • Heat to boiling while shaking frequently to dissolve completely.
   • Sterilize in an autoclave at 121°C for 15 minutes.
   • Mix well and distribute into final containers.
2. Reheating:
   • If the medium is not freshly prepared, reheat and remelt before use to expel dissolved oxygen.

Test Procedure

1. Inoculation:
   • Inoculate the medium using either:
     • Streaking: Spread the sample on the agar surface.
     • Pour Plate Method: Incorporate the sample into the molten agar before solidification.
2. Incubation:
   • Incubate anaerobically at 35 ± 2°C for 18–48 hours.
   • Extended incubation may be needed for some strict anaerobes.
3. Special Method:
   • Use a Brewer’s lid to create a microaerophilic environment without anaerobic equipment.

Interpreting Results

• Observe microbial growth patterns:
  • Growth of facultative and strict anaerobes indicates successful culture conditions.
  • Resazurin color change suggests aerobic contamination or insufficient anaerobiosis.

Quality Control

1. Dehydrated Medium:
   • Free-flowing, homogeneous, beige powder.
2. Prepared Medium:
   • Clear, light green appearance.
3. Expected Cultural Response:
   • Bacteroides fragilis (ATCC 25285): Good anaerobic growth.
   • Clostridium perfringens (ATCC 13124): Good anaerobic growth.
   • Clostridium sporogenes (ATCC 19404): Good anaerobic growth.

Storage and Shelf Life

• Dehydrated Medium:
  • Store at 10-30°C in a dry environment in its original, tightly sealed container.
  • Shelf life: 4 years.
• Prepared Medium:
  • Store at 2-8°C, away from light.
  • Use before the expiry date or if signs of contamination or deterioration appear.

Warnings and Precautions

1. For professional use only by trained laboratory personnel.
2. Consult the Safety Data Sheet (SDS) for safe handling practices.
3. Dispose of waste in compliance with local regulations.

Applications

1. Clinical Microbiology:
   • Isolation and cultivation of Clostridium and other anaerobic bacteria from clinical specimens.
2. Food and Environmental Testing:
   • Detection of anaerobes in food and environmental samples.
3. Research:
   • Study of facultative and strict anaerobes in controlled laboratory conditions.

Packaging Information

• Format: Powder
• Packaging: 500 g bottle
• Product Reference: 610320

Advantages

• Effective growth of anaerobes without advanced anaerobic chambers when using Brewer’s lids.
• Versatile application in clinical, food, and environmental microbiology.
• Clear visual indicator for anaerobic conditions via resazurin.

This agar is a valuable tool for laboratories working with anaerobic and microaerophilic organisms.