Tampons shouldn't be worn overnight because... 1  Tampons need to be changed every 4-6 hours and many people sleep longer than this - changing often is important as tampons allow bacterial growth while preventing vaginal cleaning so the longer a tampon is worn the more bacteria can multiply within the vagina.
MacConkey agar is a selective medium containing bile salts and crystal violet that inhibits the growth of Gram-positive bacteria while allowing for the growth of Gram-negative bacteria.MacConkey agar is often used when investigating and culturing fecal bacteria.he MacConkey agar we talked about as an example of a selective media is also a differential media. In addition to the selective bile salts and crystal violet, MacConkey agar contains a pH indicator and the sugar lactose.
Answers. Relevance. Rating Newest Oldest. Best Answer: Selective media is a type of media that selects for the growth of one type of organism, while inhibiting the growth of others. An example of Selective media is MacKonkey Agar. MacConkeyâs Agar is selective for gram-negative bacteria, while inhibiting the growth of gram-positive bacteria. Blood Agar is solely a differential media. This media is a nutrient agar that is differential for hemolysis. It is based on the ability of a microorganism to destroy hemoglobin and red blood cells.