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Dermatophyte Test Medium with Chloramphenicol & Cyclohexamide (Actidione) This is a selective medium for the isolation of dermatophytes that includes a Phenol Red indicator to assist in the differentiation between dermatophytes and other pathogenic fungi. Although the low pH (5.5) of the medium inhibits most bacteria, Chloramphenicol is added to further reduce the risk when processing material that may be more heavily contaminated. Cyclohexamide (Actidione) is also added to suppress the growth of most yeasts and saprophytic fungi. Dermatophytes appear as fluffy white colonies and produce a red colour on the medium while other fungi cause the medium to become yellow due to acid production. Yeasts will also grow on this medium but are readily distinguished by their distinct white/creamy colonies and distinctive smell. NB: Prolonged incubation should be avoided as this may cause fungi other than dermatophytes to turn the medium red -
Desoxycholate Citrate Agar (DCA) (Hynes) One of several media designed for the differential selective isolation of Salmonella and Shigella spp from clinical and environmental samples. Lactose is added to the medium together with Neutral Red indicator to assist in the differentiation of Lactose and Non-Lactose fermenting organisms. The medium is made selective by the inclusion of Sodium Desoxycholate and Sodium Thiosulphate, which will inhibit most gram-positive organisms. The Sodium Thiosulphate is also broken down by the enzyme thiosulphate reductase to form Sodium Sulphite and Hydrogen Sulphide. The Hydrogen Sulphide, if present, will in turn react with the ferric ions to produce a black precipitate of Ferrous Sulphide and give rise to the classical black centre of most Salmonellae. It has been suggested that this medium may be more suitable for secondary post-enrichment isolation while the original formulation is more appropriate for the primary inoculation of samples. -
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. -
Edwards Medium (Modified) with 7% Sheep Blood This is a medium for the selective isolation of streptococci, particularly Streptococcus agalactiae, involved in bovine mastitis. The medium is enriched by the addition of 7% Sheep Blood and made selective by the inclusion of Crystal Violet and Thallous Sulphate. Aesculin is also present and assists in the differentiation of Streptococcus agalactiae, which give rise to blue colonies, from Aesculin positive Group D streptococci which produce black colonies. -
Fastidious Anaerobe Agar is intended as a primary isolation medium capable of supporting most clinically significant anaerobes including fastidious organisms. The formulation is complex and includes detoxification agents (Starch & Sodium Bicarbonate), growth enhancing agents (Cysteine, Arginine, Vitamin K, Sodium Succinate, Glucose and pyrophosphate) as well as Haemin to encourage pigment production in Porphyromonas melaninogenicus. Sodium Pyruvate is also included to help neutralise Hydrogen Peroxide. One side of the bi-plate consists of standard FAA supplemented with 7% horse blood; the other side is FAA with horse blood and Neomycin (75mg/L) for the selective isolation of target organisms. -
Fastidious Anaerobe Agar (FAA) with 5% Sheep Blood Fastidious Anaerobe Agar is intended as a primary isolation medium capable of supporting most clinically significant anaerobes including fastidious organisms. The formulation is complex and includes detoxification agents (Starch & Sodium Bicarbonate) growth enhancing agents (Cysteine, Arginine, Vitamin K, Sodium Succinate, Glucose and pyrophosphate) as well as Haemin to encourage pigment production in Porphyromonas melaninogenicus. Sodium Pyruvate is also included to help neutralise Hydrogen Peroxide. In this instance the medium is further enriched by the addition of 5% Sheep Blood. -
Fastidious Anaerobe Agar is intended as a primary isolation medium capable of supporting most clinically significant anaerobes including fastidious organisms. The formulation is complex and includes detoxification agents (starch and sodium bicarbonate), growth enhancing agents (cysteine, arginine, vitamin K, sodium succinate, glucose and pyrophosphate), as well as haemin to encourage pigment production in Porphyromonas melaninogenicus. Sodium pyruvate is also included to help neutralise hydrogen peroxide. In this instance the medium is further enriched by the addition of 5% horse blood. This product is suitable for use with the EUCAST disc diffusion method for selected rapidly growing anaerobic bacteria.
