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This is a selective medium for the isolation and differentiation of bile tolerant gram-negative (enteric) and gram-positive (staphylococci and enterococci) organisms and has uses in all areas of bacteriology. It has the disadvantage that many strains of Proteus spp will spread on it and for this reason MacConkey Agar without Salt may be preferred. -
This is a selective medium primarily for the isolation of Enterobacteriacae from waters & sewage. This media differs from the original MacConkey formulation in that as well as Bile Salts, Crystal Violet has been included as an additional selective agent. This has the effect of inhibiting gram-positive micrococci. -
This is a medium for the cultivation of yeasts and moulds. The high carbohydrate content is said to ensure rapid growth while the low pH (5.4) inhibits most bacteria. Malt Extract Agar can also be used for the cultivation of fungi although with the prolonged incubation necessary cultures may become overgrown by bacteria. -
A selective medium for the isolation of Staphylococcus aureus. The high level of Sodium Chloride inhibits most other organisms and as most Staphylococcus aureus ferment Mannitol the inclusion of Phenol Red indicator gives rise to yellow colonies. This formulation complies with the requirements of the Harmonised USP/EP/JP. NB: Some strains of coagulase negative staphylococci can give rise to false positive results on this medium It is necessary therefore to confirm the identity of Staphylococcus aureus by other confirmatory tests (e.g. Coagulase test, Latex test etc.) -
Middlebrooks 7H10 Selective Medium is an Agar based medium for the isolation of Mycobacteria spp from clinical specimens. It differs from Middlebrooks 7H11 Agar in that it has a lower concentration of Malachite Green, which is said by some workers to make it more suitable for primary isolation. The medium is complex but includes L-Glutamic Acid, Ammonium Sulphate, Sodium Citrate, Pyridoxine and Biotin as growth factors and Magnesium Sulphate, Ferric Ammonium Citrate as sources of trace ions. Further enrichment is provided by the addition of Oleic Acid, Albumen and Dextrose and it is made selective by the inclusion of Ticarcillin, Polymixin B, Trimethoprim and Amphotericin B. As with egg media Glycerol is included to enhance the growth of the Mycobacteria and Malachite Green is incorporated to provide a colour contrast between the colonies and the medium as well as contributing some inhibitory effect on organisms other than mycobacteria. -
This medium is used for the presumptive identification of Pseudomonas aeruginosa from water and environmental samples. Pseudomonas aeruginosa is presumptively identified by the characteristic green pigmentation of the colonies with hydrolysis of casein (clear zones around each colony). -
Based on Fastidious Anaerobe Agar Base with added Egg Yolk Emulsion, this medium can be used to test Clostridium perfringens for phospholipase production. A zone of opalescence around the colonies is indicative of a positive reaction. It can also be used as an aid to identification of Clostridium perfringens if antitoxin is spread onto half of the plate prior to inoculation (Nagler Reaction). -
A basic general-purpose medium suitable for use in the cultivation of the less fastidious organisms particularly those that do not require the addition of blood or other enrichment. -
This is an established medium, with a neutral pH, used for the enumeration of Yeasts and Moulds -
This is a selective differential medium for the isolation of Listeria monocytogenes from food, clinical and environmental specimens. -
This medium is recommended for the detection and enumeration of yeasts and fungi in a variety of sample types. The low pH (5.6) and addition of streptomycin will ensure that the growth of most bacterial species is inhibited and the low mineral content ensures good pigment production by fungi where appropriate. -
Chromogenic Coliform Agar (CCA) Chromogenic Coliform Agar (CCA) conforms to the ISO 9308-1 guidelines for the detection, enumeration and isolation of coliforms and more specifically Escherichia coli in water samples by the membrane-filtration technique. The colonial differentiation is provided by the chromogenic substrates, Salmon-GAL and X-glucuronide. Salmon-GAL is used for the detection of β-D-galactosidase enzymatic activity. X-glucuronide is used for the detection of β-D-Glucoronidase enzymatic activity. β-D-galactosidase, expressed by all coliforms, cleaves the Salmon-GAL substrate and producing red/pink coloured colonies. Unlike other coliforms, Escherichia coli leaves both Salmon-GAL and X-glucuronide producing a violet/blue coloured colonies. Tryptophan is used to increase detection reliability by improving the indole reaction. The peptones, sodium pyruvate and sorbitol support bacterial growth and simple recovery of sub-lethal thermally injured coliforms. Sodium di-hydrogen phosphate and di-sodium hydrogen phosphate phosphate buffer the medium and sodium chloride is used to achieve osmotic balance. The selectivity is attained by the addition of Tergitol® 7 as it inhibits the growth of Gram positive bacteria. -
Tryptone Bile X (TBX) - Glucuronide Agar Recent developments in culture media have given rise to the use of chromogenic substrates as a means of differentiating bacteria particularly among the coliform group of organisms. This is one such medium and has been developed as a selective medium for the isolation and enumeration of Escherichia coli in food samples. Based on Tryptone Bile Agar it incorporates the chromogenic agent X-glucuronide, which detects glucuronidase activity, the same enzyme as is detected by MUG reagent. Escherichia coli can be differentiated from other coliform organisms by the presence of glucuronidase resulting in the colonies being blue/green while the other coliforms are colourless. For information on the full technical detail as to the functionality of this medium reference should be made to the many publications available. -
Pseudomonas Agar Base with 1% Glycerol, Cephalothin, Fucidin & Cetrimide (CFC) This is a selective medium for the isolation of Pseudomonas spp primarily in food, water and environmental samples. The medium uses Magnesium and Potassium salts to enhance pigment production and is made selective by the addition of CFC supplement. 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. -
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. -
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. -
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 general-purpose medium which supports the growth of a wide range of organisms. It is suitable for Phage Typing, Colicine Typing and for testing the X and V requirements of Haemophilus spp as well as many other areas of bacteriological investigation and conforms to the requirements of the United States Pharmacopeia for sterility testing of pharmaceutical products.
