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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.
