-
DN'ase Medium DNase Agar is used primarily in clinical laboratories to differentiate Staphylococcus aureus from other Staphylococci based on deoxyribonuclease activity. Following incubation of the plate and confirmation of a pure growth of Staphylococci, the surface of the medium is covered with a small quantity of 1M Hydrochloric Acid to precipitate the DNA. Staphylococcus aureus produce DNase enzymes that hydrolyse DNA resulting in a clear area around the colonies, described as being DNase positive, whereas coagulase negative Staphylococci do not produce clearing. NB: As with most tests of this type a positive result should not be taken in isolation and other appropriate tests, e.g. Coagulase Test, Latex Agglutination etc, should be carried out. -
DNase Agar is used primarily in clinical laboratories to differentiate Staphylococcus aureus from other staphylococci based on deoxyribonuclease activity. Staphylococcus aureus produce DNase enzymes that hydrolyse DNA resulting in a colourless zone around the colonies, described as being DNase positive, whereas coagulase negative staphylococci do not produce clearing. This particular formulation can also be used for Streptococci and Serratia. NB: As with most tests of this type a positive result should not be taken in isolation and other appropriate tests, e.g. Coagulase Test, Latex Agglutination etc, should be carried out. -
This medium was initially intended for the selective isolation of Shigella spp. but can also be used for Salmonella spp. primarily from clinical specimens although it has been used in the examination of dairy products. The medium contains high levels of Peptone to counteract some of the toxic effects, particularly on Shigella, of the Bile Salts used to make the medium selective. In addition to Lactose, Sucrose and Salicin are also included allowing for improved differentiation than with Lactose only. The presence of H2S is detected by the reaction between Ammonium Ferric Citrate and Sodium Thiosulphate. A double indicator system of Acid Fuchsin and Bromothymol Blue is helpful in the differentiation process. -
This is a selective medium for the isolation and enumeration of enterococci (Group D streptococci) primarily in food although it has found uses in other areas of bacteriology. The medium is made selective by the inclusion of Kanamycin and Sodium Azide while Aesculin and Ferric Ammonium Citrate act as the indicator system. -
Legionella Cystine Free Medium is intended for use in conjunction with Legionella CYE Medium (PP0200) as a secondary diagnostic medium for confirmation of a previously isolated organism. Although it contains Ferric Pyrophosphate and α-ketoglutarate it does not contain any L-Cysteine Hydrochloride. NB : This is a base medium only and will not sustain the growth of Legionella spp. -
This is a selective medium for the isolation of Legionella spp is used primarily in water and environmental laboratories. The base agar contains Yeast Extract as a source of protein, Charcoal to neutralise growth-inhibiting substances and is supplemented with Ferric Pyrophosphate as a source of iron, L-cysteine hydrochloride and α-ketoglutarate to form amino acid and chelate respectively. ACES buffer is incorporated to maintain the optimal pH for growth. The medium is made selective by the addition of Glycine, Vancomycin & Polymyxin B to inhibit the majority of gram positive and gram negative organisms and Cycloheximide is also included to inhibit yeasts and fungi. -
This is a basic medium for the cultivation of Legionella spp. It is intended primarily for use as a secondary diagnostic medium in conjunction with Legionella Cystine Free Medium (PP0201) for confirmation of a previously isolated organism. NB: This is a basal medium only and although it will sustain the growth of Legionella spp. It contains no selective supplements. It is therefore not recommended as a means of primary isolations from clinical samples. -
One of several media available as a selective identification medium for the isolation and identification of Listeria monocytogenes in food & clinical laboratories. Using Columbia Agar as the base Lithium Chloride is included to inhibit enterococci and Acriflavine to inhibit some other gram positive and gram negative organisms that may be present in such specimens. It is made further selective by the addition of the antimicrobials Cefoxitin, Colistin & Fosfomycin with Amphotericin included to inhibit any yeasts present. Aesculin is present as an indicator since Listeria monocytogenes will hydrolyse it and the associated reaction with the Ferric Ammonium Citrate gives rise to a black precipitate around the colonies. -
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.
