MacConkey Agar with Polycolistin B and Gentamycin

Principle: Peptone provides basic nutrients for bacterial growth, sodium chloride maintains osmotic pressure, polymyxin B mainly inhibits the growth of most Gram-negative bacteria, gentamicin is a broad-spectrum antibiotic, which has an inhibitory effect on a variety of Gram-negative bacteria and positive bacteria, bovine bile salt can mainly inhibit the growth of Gram-positive bacteria, lactose is a fermentable carbon source, neutral red is an acid-base indicator, Burkholderia cepacia does not ferment lactose, and the colonies are usually yellow-brown or reddish, The surrounding medium usually does not change color or turns orange-yellow due to alkali production, while lactose-fermenting bacteria are peachy on the medium and may have a precipitate ring around the colony to distinguish them from Burkholderia cepacia. Usage: weigh 54. 03g of this product, heat and boil, completely dissolve in 1000ml distilled water, divide into triangular bottles, autoclave at 115 ℃ for 20 minutes, and when cooled to about 50 ℃, add filtered and sterilized polymyxin B 25000U and gentamicin 1mg per 100ml of culture medium, mix well, pour into a sterile dish, and set aside.