Plot No. C40, Road No. 21Y, MIDC, Wagle Industrial Estate,
Thane(W)-400604, MH, India.
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Intended Use
Recommended for heterotrophic plate count of treated potable water using longer incubation periods.
Composition
| Ingredients | g/L |
|---|---|
| Casitose # | 0.500 |
| Yeast extract | 0.500 |
| Proteose peptone | 0.500 |
| Dextrose (Glucose) | 0.500 |
| Starch | 0.500 |
| Dipotassium hydrogen phosphate | 0.300 |
| Magnesium sulphate | 0.024 |
| Sodium pyruvate | 0.300 |
| Agar | 15.000 |
| Final pH (at 25°C) | 7.2±0.2 |
**Formula adjusted, standardized to suit performance parameters
# Equivalent to Casein hydrolysate
Directions
R-2A Agar is a ready to use solid media in glass bottle. The medium is pre-sterilized, hence it does not need sterilization. Medium in the bottle can be melted either by using a pre-heated water bath or any other method. Slightly loosen the cap before melting. When complete melting of medium is observed dispense the medium in tubes as butts /slants or in plates as desired and allow to solidify. If on plate, either streak, inoculate or surface spread the test inoculum (50-100 CFU) aseptically.
Principle And Interpretation
Agar Medium S (R-2 A Agar) is used for the heterotrophic plate counts and for sub culturing isolates from potable waters using longer incubation periods was developed by Reasoner (1). The composition is as recommended by European Pharmacopoeia (2). It is recommended for pour plate, spread plate and membrane filter techniques. Plate count recommended for the bacterial examination of potable waters, gives an estimate of the aerobic and facultatively anaerobic bacteria, which grow best at 35°C on a rich medium (3). However these organisms may represent a small number of total bacteria as other bacteria are either unable to grow under these conditions, or grow very slowly which cannot be detected in48hours.
R-2 A Agar is modified for better recovery of these bacteria from treated waters under different incubation conditions (3). Many bacteria from natural waters, which contain limited nutrients at ambient temperature, grow best on the media with less nutrient levels. Moreover, they grow better at the temperatures below the routine laboratory incubation temperatures of 35 to 37°C (3). R-2 A Agar, Modified is a low nutrient medium consisting of less proteose peptone, yeast extract and glucose as compared to Standard Methods Agar. This medium allows the growth of stressed, injured and chlorine tolerant bacteria present in treated waters due to the presence of pyruvate and starch. The number of colonies on a plate is reported as CFU (Colony Forming Units) per volume of sample.
Type of specimen
Pharmaceutical water samples
Specimen Collection and Handling
For water samples, follow appropriate techniques for sample collection, processing as per guidelines and local standard (3). 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
- Longer incubation time other than specified is required for slow growing microorganisms.
- The media is intended for water samples for recovery of stressed or injured organisms.
- Individual organisms differ in their growth requirement and may show variable growth patterns on the medium.
- Each lot of the medium has been tested for the organisms specified on the COA. It is recommended to users to validate the medium for any specific microorganism other than mentioned in the COA based on the user's unique requirement.
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: Sterile glass bottle containing slightly opalescent R-2A Agar.
Colour medium: Light amber coloured medium.
Quantity of medium: 250 ml of medium in glass bottle.
pH: 7.00-7.40
Sterility Check: Passes release criteria
Cultural Response
Cultural characteristics observed *by using standard ATCC cultures after an incubation at 30-35°C for 24-72 hours. (*-In case of water samples from fields it is suggested to incubate further for upto 7 days to ascertain the absence of organisms)
| Organism | Inoculum (CFU) | Growth | Observed Lot value (CFU) | Recovery |
|---|---|---|---|---|
| Candida albicans ATCC 10231 (00054*) | 50-100 | good-luxuriant | 25-100 | >=50% |
| Escherichia coli ATCC 25922 (00013*) | 50-100 | good-luxuriant | 25-100 | >=50% |
| Salmonella Enteritidis ATCC 13076 (00030*) | 50-100 | good-luxuriant | 25-100 | >=50% |
| ^Pseudomonas paraeruginosa ATCC 9027 (00026*) | 50-100 | good-luxuriant | 25-100 | >=50% |
| Staphylococcus aureus subsp. aureus ATCC 6538 (00032*) | 50-100 | good-luxuriant | 25-100 | >=50% |
| ** Bacillus spizizenii ATCC 6633 (00003*) | 50-100 | good-luxuriant | 25-100 | >=50% |
| # Aspergillus brasiliensis ATCC 16404 | 50-100 | good-luxuriant | 25-100 | >=50% |
| Enterococcus faecalis ATCC 29212 (00087*) | 50-100 | good-luxuriant | 25-100 | >=50% |
| Escherichia coli ATCC 8739 (00012*) | 50-100 | good-luxuriant | 25-100 | >=50% |
Key: * Corresponding WDCM numbers.
^ Formerly known as Pseudomonas aeruginosa
# Formerly known as Aspergillus niger
**Formerly known as Bacillus subtilis subsp. spizizenii
Storage and Shelf Life
On receipt store between 15-30°C Use before expiry date on the label. 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 (4,5).
| Product Name | R2A Agar |
|---|---|
| SKU | SME962CCL |
| Customized Product Available | No |
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