Liofilchem® Aeromonas Agar Base

Liofilchem® Aeromonas Agar Base is a basal medium designed for the selective isolation and presumptive identification of Aeromonas species from various samples, including food, water, and environmental sources. When used with Ampicillin Supplement (Ref. 81001), the medium effectively suppresses contaminating flora, facilitating the detection and recovery of Aeromonas spp.

Key Features

• Selective Enrichment: Formulated to support the growth of Aeromonas spp. while inhibiting Gram-positive bacteria and other non-target microorganisms.
• Multi-Sample Use: Applicable to water samples (tap, bottled), food (meat, poultry, seafood, raw milk), and environmental samples.
• Differentiation: Enables visual identification of presumptive Aeromonas colonies via distinctive colony morphology and color changes.
• Optimized pH: Maintains a stable alkaline pH (8.0 ± 0.1), ideal for Aeromonas species recovery.

Typical Formula (g/L)

Principle of Action

1. Nutritional Support:
   • Proteose Peptone and yeast extract supply essential amino acids, nitrogen, carbon, and vitamins to support Aeromonas growth.
2. Selective Agents:
   • Bile salts inhibit Gram-positive bacteria.
   • The addition of Ampicillin Supplement further suppresses competing microorganisms.
3. Differentiation Mechanisms:
   • Sodium thiosulfate reacts with ferric ammonium citrate to form a black precipitate in H₂S-producing colonies.
   • Bromothymol blue and thymol blue change color in response to acid production from carbohydrate fermentation, turning colonies dark green with darker centers.

Preparation Instructions

1. Suspend 58.8 g of the dehydrated medium in 1 liter of distilled or deionized water.
2. Heat to boiling while stirring to dissolve completely.
3. Do not autoclave.
4. Cool the solution to 45–50°C.
5. Aseptically add the reconstituted contents of 2 vials of Ampicillin Supplement (Ref. 81001) (each vial contains 2.5 mg of Ampicillin).
6. Mix thoroughly and pour into sterile Petri dishes.

Technique and Application

1. Inoculation:
   • Apply samples to the medium using spread plating or membrane filtration techniques.
2. Incubation:
   • Incubate plates aerobically at 30–35°C for 18–24 hours.
   • If further incubation is required, hold plates at room temperature (22–25°C).
3. Results Interpretation:
   • Look for dark green opaque colonies with darker centers.
   • Confirm Aeromonas spp. by subculturing to non-selective media and performing the following tests:
     • Oxidase test (positive indicates Aeromonas spp.).
     • Trehalose fermentation test (positive indicates Aeromonas spp.).

Microbiological Quality Control

Applications

1. Water Testing:
   • Detect Aeromonas spp. in tap water, bottled water, or chlorinated water supplies.
2. Food Microbiology:
   • Isolate Aeromonas spp. from meat, poultry, seafood, raw milk, and other raw foods.
3. Environmental Monitoring:
   • Analyze environmental samples, such as surface water, for Aeromonas spp. contamination.

Storage and Stability

• Dehydrated Medium: Store at 10–30°C in a dry environment, tightly sealed in its original container.
• Prepared Plates: Store at 2–8°C away from light.
• Shelf life: 4 years when stored under proper conditions.

Appearance

Precautions

• For professional use only. Operators must be trained in laboratory techniques.
• Strictly follow the instructions to ensure reliable results.
• Dispose of waste according to local and national regulations.

Packaging

References

1. Standard Methods for the Examination of Water and Wastewater (1998). 20th Ed. American Public Health Association.
2. Handfield, M., et al. (1996). Differential media for quantitative recovery of waterborne Aeromonas hydrophila. Appl. Environ. Microbiol., 62:3544–3547.

Liofilchem® Aeromonas Agar Base is an essential tool for microbiologists investigating the presence of Aeromonas species in water, food, and environmental samples. Its optimized composition, in conjunction with Ampicillin Supplement, ensures high selectivity and sensitivity for the isolation of these organisms.