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Hektoen Enteric (HE) Agar: Introduction, Composition, Principle, Procedure, Results Interpretation, Uses and Limitations
Introduction of Hektoen Enteric (HE) Agar Hektoen enteric (HE) agar was developed in 1968 by Sylvia King and William I. Metzger in an effort to increase the recovery of Salmonella and Shigella species over the previously formulated Salmonella-Shigella (SS) Agar. This is also known as HEK and HEA. This medium is particularly useful in the isolation of Shigella species. They formulated HE Agar medium while working at the Hektoen Institute in Chicago and became able to increase...
Sorbitol MacConkey Agar (SMAC): Introduction, Composition, Principle, Procedure, Results Interpretation, Uses and Limitations
Introduction of Sorbitol MacConkey Agar (SMAC) Sorbitol MacConkey Agar (SMAC) is recommended for the isolation of Escherichia coli O157:H7. Rappaport and Henig first described the formulation of the medium, and it was later confirmed by March and Ratham who reported MacConkey Agar with Sorbitol to have a sensitivity of 100% and a specificity of 85%. This SMAC medium has proved to be an inexpensive, rapid, simple yet reliable means for the detection of E. coli O157:H7. It is...
Salmonella-Shigella (SS) Agar: Introduction, Composition, Principle, Procedure, Results Interpretation, Uses and Limitations
Introduction of Salmonella-Shigella (SS) Agar Salmonella-Shigella (SS) Agar is recommended for use as a selective and differential medium for the isolation of Salmonella and some Shigella species from clinical and non-clinical specimens( suspected foodstuffs). Composition of Salmonella-Shigella (SS) Agar (Himedia) Ingredients Gms / Litre Proteose peptone 5.0 Lactose 10.0 Bile salts mixture 8.5 Sodium citrate 8.5 Sodium thiosulphate 8.5 Ferric citrate 1.0 Brilliant green 0.00033 Neutral red 0.025 Agar 13.5 Distilled water: 1000 ml Final pH...