ENDO LES AGAR BASE 500 grams/bottle

Endo LES Agar Base is a modification of Endo Agar Base (Cat. 1118), for testing water by the membrane filter technique. It uses Lauryl Sulfate Broth (Cat. 1310) as previous enrichment, obtaining greater growth. LES stands for Lawrence Experimental Station. It is a standard formula for testing waters and is also specified in the coliforms fermentation technique. Like Endo Agar, it uses fuchsin to differentiate between positive lactose-fermenting and lactose non fermenting bacteria. Acetaldehyde production by lactose fermenting organisms such as Escherichia coli produce characteristic red colonies and a red surrounding area, marked by its reaction with Sodium sulfite in the presence of fuchsin. Lactose non-fermenters form colorless, transparent colonies. Casein and Meat peptones, and Tryptose provide nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group. Lactose is the fermentable carbohydrate providing carbon and energy. Potassium phosphates act as a buffer system. Sodium desoxycholate inhibit growth of gram positive bacteria. Sodium lauryl sulphate partially inhibits organisms other than coliforms. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Bacteriological agar is the solidifying agent. Note: Basic fuchsin is a potential carcinogen and precautions should be taken to avoid inhalation of the dye powder as well as contact with skin.