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Pseudomonas Agar Base with 1% Glycerol & CN Supplement A selective medium for the isolation of Pseudomonas aeruginosa the medium is made selective by the inclusion of Cetrimide and Naladixic Acid (CN) supplement to significantly reduce the enteric organisms particularly Proteus and Klebsiella spp. Magnesium and Potassium salts are included to enhance the production of the pigments pyocyanin and fluorescein. -
A selective medium for the isolation of Pseudomonas spp. primarily in food, water and environmental samples the medium is made selective by the addition of CFC supplement (cetrimide, at a concentration of 10mg/L which is said to allow the growth of all pseudomonads, cephalothin and fucidin). The presence of blue/green or brown pigmentation or fluorescence is indicative of presumptive Pseudomonas spp. It should be noted however that further testing must be carried out to confirm the full identity of the organism. -
R2A medium was developed to determine the bacterial count including heterotrophic bacteria in potable waters during treatment and distribution. This medium has a low nutritional content and therefore requires extended incubation times. It is recommended by the Environmental Agency, Methods for the Examination of Waters and Associated Materials, and Standard Methods for the Enumeration of Water and Wastewater. -
RPMI Medium for E-Test RPMI Medium is recommended for use in anti-fungal susceptibility testing of yeasts from clinical isolates using the E-Test method. The medium is based on a simple Glucose Agar with added RPMI-1640 Medium (without Sodium Bicarbonate & Phenol Red), which supplies the necessary vitamins and amino-acids, and MOPS (3-(Morpholino)propanesulfonic Acid) Buffer to maintain the medium pH during incubation. -
Sabouraud Dextrose Agar with Chloramphenicol (0.5g/L) is a selective media for the isolation of yeasts and fungi suitable for use in all areas of mycology. Sabouraud dextrose agar is a modification of a medium originally described by Sabouraud.(1) The tryptone and meat peptone provides the required nitrogen, carbon and vitamins. The high concentration of dextrose is included as an energy source. Due to the higher pH of the medium, an increased concentration of chloramphenicol is included to improve the selectivity of the media and inhibit a range of Gram-positive and Gram negative bacteria. 1. Sabouraud, R. 1892. Ann. Dermatol. Syphilol. 3:1061. -
Sabouraud Dextrose Agar with Chloramphenicol (50mg/L) & Cyclohexamide (Actidione) (300mg/L) A selective medium for the isolation of fungi, Sabouraud Dextrose Agar is suitable for use in all areas of Mycology. The low pH of the medium inhibits most bacteria however in this formulation Chloramphenicol (50mg/L) is added to further reduce the risk when processing material that may be heavily contaminated particularly with coliforms. Cycloheximide is also added to suppress the growth of yeasts and saprophytic fungi. -
This is a modification of Sabouraud Dextrose Agar. The low pH (5.6) of the medium is inhibitory to most bacteria and it has been made specifically selective by the addition of colistin and gentamicin. This further reduces the risk of bacterial contamination when processing material that may be heavily contaminated particularly with Gram negative organisms such as Pseudomonas aeruginosa. -
Originally intended as a medium for the enumeration of enterococci in water using Membrane Filtration, this medium has become more popular in many other areas such as food bacteriology. The medium contains Tetrazolium Chloride, which is reduced by enterococci to the insoluble red dye Formazan resulting in dark red colonies of enterococci on the agar. It should be noted that this reaction is not exclusive to enterococci and colonies should be confirmed by additional testing e.g. Aesculin hydrolysis. -
This is a differential medium for the isolation of Escherichia coli 0157:H7. It differs from other MacConkey media in that lactose has been replaced by sorbitol. As Escherichia coli 0157:H7 does not ferment sorbitol, it produces pale translucent colonies whereas most other strains of Escherichia coli do ferment sorbitol and produce pink colonies. -
Sorbitol MacConkey with Cefixime & Tellurite (CT-Smac) This is a selective differential medium for the isolation of Escherichia coli 0157:H7. It differs from other MacConkey medium in that Lactose has been replaced by Sorbitol. As Escherichia coli 0157:H7 does not ferment Sorbitol it produces pale translucent colonies whereas most other strains of Escherichia coli are Sorbitol positive and produce pink colonies. The medium is made more selective by the addition of the antimicrobial Cefixime and Potassium Tellurite. -
Thiosulphate Citrate Bile Salts Sucrose (TCBS) Agar TCBS is a selective isolation medium for culture of pathogenic Vibrio spp. from clinical samples. The formulation was developed by Kobayashi, Enomoto, Skazaki and Kuwahara. This medium inhibits most enterobacteriacae for at least 24 hours. For the isolation of Vibrio spp. other than V.cholerae in environmental bacteriology, it is advisable to incubate at the lower temperature range of 20°C – 30°C. NB - It is not recommended to perform an oxidase test on any presumptive positive isolates directly from TCBS medium. -
This is a medium to detect Thermo-Stable-Nuclease from Staphylococcus aureus after heat inactivation of the organism. After boiling and centrifugation the supernatant is placed in a well in the plate and incubated for 4 hours. If present, the enzyme breaks down the DNA in the medium and produces a zone of clearing indicating a positive reaction. -
Triphenyltetrazolium Chloride Soya Tryptone (TSAT) Agar Complete Triphenyltetrazolium Chloride (TTC) has been added as an indicator to various media, and recommended by several workers as being helpful in the early recognition and identification of a variety of bacteria including Escherichia coli, Vibrio parahaemolyticus and enterococci. This particular formulation is based on a Tryptone Soya Agar with added Sucrose and is particularly useful when performing counts on food and food product samples. Many of the enterobacteriaceae and enterococci will reduce the TTC to a formazan which colours the colonies deep red making them easier to distinguish and identify. The presence of the Sucrose can also assist in the differentiation of Sucrose fermenting and non-fermenting strains. -
This is a plate count agar originally suggested by the American public Health Association for the estimation of total viable counts in food and dairy products. -
This is a medium for determining the mutagenicity of a chemical reagent using the Ames Test. A histidine requiring strain (His- ) of Salmonella typhimurium is inoculated into a mixture of salt agar, histidine solution and the test reagent, which is mixed and then used to overlay the media. Following incubation if the test reagent is mutagenic it will reverse the His- phenotype allowing growth to occur at a higher level than the control. -
Originally introduced as an aid to recovery of Shigella spp. XLD is also a first class medium for recovery of Salmonella spp. It differs from other media of this type in that it has less Sodium Desoxycholate as its selective agent. The indicator system is somewhat complex taking advantage of the fermentation or otherwise of three carbohydrates (Lactose Sucrose and Xylose) together with Lysine Decarboxylase and Sodium Thiosulphate as an indication of the presence or absence of Hydrogen Sulphide.
