B.A.G.G. Broth Base (Buffered Azide Glucose Glycerol Broth Base)

Intended Use

Recommended for selective cultivation and detection of faecal Streptococci (group D) from clinical and sanitary samples.

Composition**

Final pH (at 25°C): 6.9±0.2

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 36.01 grams in 1000 ml purified/distilled water containing 5 ml glycerol. Heat if necessary to dissolve the medium completely and dispense in test tubes in 10 ml amounts. Sterilize by autoclaving at 115°C (10 lbs pressure) for 15 minutes.

Note: Autoclaving at 15 lbs pressure (121°C) is not recommended. The concentration of the medium must be adjusted to suit sample volume. For smaller inocula such as clinical specimens, faeces and small sanitary specimens like water, single strength medium is used but for larger inocula such as larger sanitary and water specimens double strength medium is necessary.

Principle And Interpretation

Enterococci are commensals of the gut and are low-grade pathogens. However in rare cases they cause urinary tract infections in catheterized patients, abdominal wound infections following gut surgery and endocarditis. Hajna and Perry developed Streptococcus faecalis Broth for the detection of faecal Streptococci, in water, milk and other materials. SF Broth is used for identification of Enterococci based on carbohydrate fermentation. Subsequently Hajna modified the medium by incorporating glycerol as additional growth factor to improve the fermentation ability of Enterococci. Also in the modified medium the concentration of the indicator dye i.e. bromocresol purple was decreased to aid easier detection and colour change within 24 hours. This modified medium is referred to as B.A.G.G Broth Base (Buffered Azide Glucose Glycerol Broth Base).

Tryptose serve as source of carbon, nitrogen, long chain amino acids, vitamins and other essential nutrients. The phosphates buffer the medium well. Sodium chloride helps to maintain the osmotic equilibrium of the medium. Sodium azide inhibits the accompanying gram-negative flora. Dextrose serves as the source of energy by being the fermentable carbohydrate. Utilization of dextrose liberates acid, indicated by bromocresol purple indicator, by changing the colour of the medium to yellow. Added glycerol serves as an additional source of energy.

The test sample can be directly inoculated into the medium. Depending upon the quantity of the test water sample, either single strength or double strength medium can be used. Presumptive faecal streptococci contained in B.A.G.G. Broth Base should be further tested for confirmation.

Type of specimen

Please add specimen

Specimen Collection and Handling

After use, contaminated materials must be sterilized by autoclaving before discarding.

Warning and Precautions

Read the label before opening the container. Wear protective gloves/protective clothing/eye protection/ face protection. Follow good microbiological lab practices while handling specimens and culture. Standard precautions as per established guidelines should be followed while handling clinical specimens. Safety guidelines may be referred in individual safety data sheets.

Limitations

1. Some strains may show poor growth due to variable nutritional requirement.
2. Further Biochemical testing is required for confirmation of species.

Performance and Evaluation

Performance of the medium is expected when used as per the direction on the label within expiry period when stored at the recommended temperature.

Quality Control

Appearance: Light yellow to light purple homogeneous free flowing powder

Colour and Clarity of prepared medium: Purple coloured, clear solution without any precipitate

Reaction: Reaction of 3.6% w/v aqueous solution containing 0.5% v/v glycerol at 25°C. pH : 6.9±0.2

Cultural Response: Cultural characteristics observed after an incubation at 45°C for 18-24 hours.

Key : *Corresponding WDCM numbers. # Formerly known as Enterobacter aerogenes

Storage and Shelf Life

Store between 10-30°C in a tightly closed container and the prepared medium at 15-25°C. Use before expiry date on the label. On opening, product should be properly stored dry, after tightly capping the bottle inorder to prevent lump formation due to the hygroscopic nature of the product. Improper storage of the product may lead to lump formation. Store in dry ventilated area protected from extremes of temperature and sources of ignition Seal the container tightly after use. Product performance is best if used within stated expiry period.

Disposal

User must ensure safe disposal by autoclaving and/or incineration of used or unusable preparations of this product. Follow established laboratory procedures in disposing of infectious materials and material that comes into contact with clinical sample must be decontaminated and disposed of in accordance with current laboratory techniques (4,5).

Reference

1. Hajna A. A. and Perry C. A., 1943, Am. J. Public Health, 33:550.
2. Hajna A. A., 1951, Public Health Lab., 9:80.
3. MacFaddin J. F., 1985, Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria, Vol. 1, Williams and Wilkins, Baltimore.
4. Isenberg, H.D. Clinical Microbiology Procedures Handbook. 2^nd Edition.
5. Jorgensen, J.H., Pfaller, M.A., Carroll, K.C., Funke, G., Landry, M.L., Richter, S.S and Warnock., D.W.(2015) Manual of Clinical Microbiology, 11th Edition. Vol. 1.