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B.T.B. Lactose HiCynth™ Agar
Intended Use
Recommended for detection and isolation of pathogenic Staphylococci.
Composition
| Ingredients | g/L |
|---|---|
| HiCynth™ Peptone No.5* | 8.000 |
| Lactose | 10.000 |
| Bromo thymol blue | 0.170 |
| Agar | 15.000 |
| Final pH (at 25°C) | 8.6±0.2 |
**Formula adjusted, standardized to suit performance parameters
*Chemically defined peptone
Directions
Suspend 33.17 gram in 1000 ml purified / distilled water. Heat to boiling to dissolve the medium completely. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. Cool to 45-50°C. Mix well and pour into sterile Petri plates.
Principle And Interpretation
Staphylococcus are frequently a part of the normal human microflora, it can cause significant opportunistic infections under appropriate conditions (1). Traditionally Staphylococci are divided into two groups on the basis of their ability to clot blood plasma (the coagulase reaction). The coagulase-positive Staphylococci constitute the most pathogenic species, Staphylococcus aureus. BTB Lactose Agar (2) designed by Chapman et al (3), is used in the detection and isolation of pathogenic Staphylococci. On this media Staphylococci are differentiated by their ability to grow at a high pH and in the presence of bromothymol blue. B.T.B. Lactose HiCynth™ Agar is prepared by replacing animal and vegetable peptones with chemically defined peptones to avoid BSE/TSE risks associated with animal peptones.
HiCynth™ Peptone No.5 serves as a source of carbon, nitrogen, long chain amino acids, vitamins and other essential nutrients. Lactose is the fermentable carbohydrate with bromothymol blue as an indicator. Plates should be inoculated preferably by spread plate technique and incubated for about 36 hours at 35°C. Typical colonies appear deep yellow (90% approx.) or blue grey (10% approx.). Coliforms may grow but are differentiated by their appearance.
Type of specimen
Food samples
Specimen Collection and Handling
For food samples, follow appropriate techniques for sample collection and processing as per guidelines (4).
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 specimens. Safety guidelines may be referred in individual safety data sheets.
Limitations
- Individual organisms differ in their growth requirement and may show variable growth patterns on the medium.
- Further biochemical and serological tests must be carried out for complete identification.
Performance and Evaluation
Performance of the medium is expected when used as per the direction on the label within the expiry period when stored at recommended temperature.
Quality Control
Appearance
Cream to greenish yellow homogeneous free flowing powder
Gelling
Firm, comparable with 1.5% Agar gel
Colour and Clarity of prepared medium
Greenish blue coloured, clear to slightly opalescent gel forms in Petri plates
Reaction
Reaction of 3.32% w/v aqueous solution at 25°C. pH : 8.6±0.2
pH
8.40-8.80
Cultural Response
Cultural characteristics observed after an incubation at 35-37°C for 24-48 hours.
| Organism | Inoculum (CFU) | Growth | Recovery | Colour of colony |
|---|---|---|---|---|
| Escherichia coli ATCC 25922 (00013*) | 50-100 | good-luxuriant >=70% | yellow | |
| Staphylococcus aureus subsp. aureus ATCC 25923 (00034*) | 50-100 | good-luxuriant >=70% | golden yellow | |
| Salmonella Typhi ATCC 6539 | 50-100 | good-luxuriant >=70% | blue/colourless | |
| Staphylococcus aureus subsp. aureus ATCC 6538 (00032*) | 50-100 | good-luxuriant >=70% | golden yellow | |
| Staphylococcus epidermidis ATCC 12228 (00036*) | 50-100 | good-luxuriant >=70% | blue/colourless |
Key: (*) Corresponding WDCM numbers.
Storage and Shelf Life
Store between 10-30°C in a tightly closed container and the prepared medium at 20-30°C. Use before expiry date on the label. On opening, product should be properly stored dry, after tightly capping the bottle in order 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 sample must be decontaminated and disposed of in accordance with current laboratory techniques (5,6).
Reference
- Carney D. N., Fossieck B. E., Parker R. H. et al, 1982, Rev. Infect. Dis. H., 1-12.
- Atlas R. M., 2004, Handbook of Microbiological Media, 3rd Edition,CRC Press.
- Chapman, Lieb, Bereus and Curcio, 1937, J. Bacteriol., 33:533.
- Salfinger Y., and Tortorello M.L., 2015, Compendium of Methods for the Microbiological Examination of Foods, 5th Ed., American Public Health Association, Washington, D.C.
- Isenberg, H.D. Clinical Microbiology Procedures Handbook 2nd Edition.
- 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.
| Product Name | B.T.B. Lactose HiCynth™ Agar |
|---|---|
| SKU | MCD861 |
| Customized Product Available | No |

