Eugon Agar and Broth

Intended Use

Eugon Agar is a general-purpose medium used for cultivating a wide variety of microorganisms.

Eugon Broth (Eugonbroth™) is a general-purpose medium used for the cultivation of fastidious and nonfastidious bacteria from a variety of clinical and nonclinical specimens.

Summary and Explanation

Eugon Agar is prepared according to the formula described by Pelczar and Vera.1 Eugon Agar and Eugon Broth were developed to obtain eugonic (luxuriant) growth of fastidious
microorganisms.2 Eugon Agar can be used with or without enrichment. Enriched with blood, Eugon Agar supports the growth of pathogenic fungi including Nocardia, Histoplasma and Blastomyces. With the addition of Supplement B, excellent growth of Neisseria, Francisella and Brucella is achieved. The unenriched medium supports rapid growth of lactobacilli associated with cured meat products, dairy products and other foods.
Niven3 reported the use of Eugon Agar for the detection of lactic acid in cured meats, and recommended it for investigating spoilage in meats. Harrison and Hansen4 employed the medium for plate counts of the intestinal flora of turkeys. Frank5 showed its usefulness in germinating anaerobic spores pasteurized at 104°C. Eugon Agar is included in the Compendium of Methods for the Microbiological Examination of Foods.6
Eugon Broth is a general-purpose medium used for the cultivation of fastidious and nonfastidious bacteria from a variety of clinical and nonclinical specimens.

Principles of the Procedure

Eugon Agar
Peptones provide the nitrogen, vitamins and amino acids in Eugon Agar. The high concentration of dextrose is the energy source for rapid growth of bacteria. L-Cystine and sodium
sulfite are added to stimulate growth. Sodium chloride maintains the osmotic balance of the media. The high carbohydrate content along with high sulfur (cystine) content improves
growth with chromogenicity.2 Agar is the solidifying agent in Eugon Agar.
Eugon Broth
Peptones supply amino acids and other nitrogenous substances to support bacterial growth. L-cystine is an essential amino acid that improves growth. Dextrose is incorporated as a source of energy and sodium chloride provides osmotic equilibrium. Sodium sulfite along with the cystine content improves growth with chromogenicity

Formula

Eugon Agar
Approximate Formula* Per Liter
Proteose Peptone No. 3................................................ 7.5 g
Pancreatic Digest of Casein.................................... ...... 7.5 g
Soy Peptone........................................................ ....... 5.0 g
Dextrose..................................................................... 5.5 g
L-Cystine.................................................................... 0.7 g
Sodium Chloride.......................................................... 4.0 g
Sodium Sulfite............................................................. 0.2 g
Agar......................................................................... 15.0 g
Eugon Broth
Approximate Formula* Per Liter
Proteose Peptone No. 3 ...............................................7.5 g
Pancreatic Digest of Casein ..........................................7.5 g
Soy Peptone ...............................................................5.0 g
Dextrose ....................................................................5.5 g
L-Cystine ...................................................................0.7 g
Sodium Chloride .........................................................4.0 g
Sodium Sulfite ............................................................0.2 g
*Adjusted and/or supplemented as required to meet performance criteria.

User Quality Control

Identity Specifications
Eugon Agar
Dehydrated Appearance: Beige, free-flowing, homogeneous.
Solution:                       4.54% solution, soluble in purified water upon
                                   boiling. Solution is light amber, very slightly to
                                   slightly opalescent, cystine precipitate may be visible.
Prepared Appearance:    Light amber, slightly opalescent, cystine precipitate
                                   may be visible.
Reaction of 4.54%
Solution at 25°C:          pH 7.0 ± 0.2
Eugon Broth
Dehydrated Appearance: Beige, free-flowing, homogeneous.
Solution:                       3.04% solution, soluble in purified water upon
                                   boiling. Solution is light amber, clear, may contain
                                   up to a large amount of precipitate.
Prepared Appearance:    Light amber, clear, may have a slight precipitate.
Reaction of 3.04%
Solution at 25°C:           pH 7.0 ± 0.2
Cultural Response
Eugon Agar
Prepare the medium (unsupplemented) per label directions. For Candida albicans and Aspergillus brasiliensis inoculate using fresh broth cultures and incubate at 30 ± 2°C for 18-48 hours. For all other cultures inoculate and incubate at 35 ± 2°C for 18-48 hours.

Eugon Broth
Prepare the medium (unsupplemented) per label directions. Inoculate and incubate with caps loosened at 35 ± 2°C (Aspergillus brasiliensis and Candida albicans at 30 ± 2°C) for up to 72 hours.

Directions for Preparation from Dehydrated Product

Eugon Agar
1. Suspend 45.4 g of the powder in 1 L of purified water. Mix thoroughly.
2. Heat with frequent agitation and boil for 1 minute to completely dissolve the powder.
3. Autoclave at 121°C for 15 minutes.
4. When an enrichment is being prepared, cool to 50-55˚C prior to adding the desired enrichment.
5. Test samples of the finished product for performance using stable, typical control cultures.
Eugon Broth
1. Suspend 30.4 g of the powder in 1 L of purified water. Mix thoroughly.
2. Heat with frequent agitation and boil for 1 minute to completely dissolve the powder.
3. Autoclave at 121°C for 15 minutes.
4. When an enriched medium is being prepared, cool to 50-55°C prior to adding the desired enrichment.
5. Test samples of the finished product for performance using stable, typical control cultures.

Procedure

Eugon Agar
For a complete discussion on bacteria and fungi from clinical specimens, refer to the appropriate procedures outlined in the references.7,8 For the examination of bacteria and fungi in food refer to standard methods.6,9
Eugon Broth
Organisms to be cultivated must first be isolated in pure culture on an appropriate solid medium. Using a sterile inoculating loop or needle, transfer fresh growth from the subculture medium to the tubed medium. Incubate under conditions appropriate for the organism being
cultivated. Broth cultures should be held at least 1 week before discarding as negative.

Expected Results

Eugon Agar
Refer to appropriate references and procedures for results.
Eugon Broth
Growth in tubes is indicated by the presence of turbidity compared to an uninoculated control. If growth appears, cultures should be examined by Gram staining, subculturing onto appropriate media and incubating inoculated media aerobically with increased CO2 and/or anaerobically.

Limitations of the Procedure

1. Eugon Agar is not recommended as a blood agar base for hemolytic reactions because of its high sugar content.
2. It is suggested that Eugon Agar be prepared as required. Do not melt and resolidify media containing enrichments.

*Store at 2-8°C.

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