What is an example of a differential medium?
A differential medium support the growth of any microbe but distinguishes them based on how they metabolize or change the medium. One example of differential medium is blood agar. Blood agar distinguishes microbes based on their ability to lyse red blood cells (RBCs), a property known as hemolysis.
What does it mean if a medium is differential?
Differential media contain compounds that allow groups of microorganisms to be visually distinguished by the appearance of the colony or the surrounding media, usually on the basis of some biochemical difference between the two groups.
Which media will be selective differential?
Hektoen agar is a selective and differential medium that helps isolate and differentiate Salmonella and Shigella from normal enteric gram-negative organisms, while preventing the growth of most gram-positive organisms.
Why is MacConkey agar both differential and selective?
MacConkey Agar (MAC) is a selective and differential medium designed to isolate and differentiate enterics based on their ability to ferment lactose. Bile salts and crystal violet inhibit the growth of Gram positive organisms. Lactose provides a source of fermentable carbohydrate, allowing for differentiation.
Is chocolate agar selective or differential?
Chocolate Agar is an enriched general- purpose medium that supports the growth of most fastidious and non-fastidious organisms. Because it is a non-selective medium, resident flora from clinical specimens may overgrow potential fastidious pathogens, such as Neisseria species.
Is pea selective or differential?
PEA agar is a selective medium that permits the growth of gram-positive cocci while inhibiting most gram-negative organisms.
Why would you use slants instead of plates for storage?
Why are agar slants better suited than agar plates to maintain stock cultures? Slants are better suited because they can be capped, preventing the agar and culture from drying out. The cap also prevents airborne contaminates from entering the slant. Slants take up less storage space.
Which media is differential?
Examples of differential media include:
- Blood agar (used in strep tests), which contains bovine heart blood that becomes transparent in the presence of hemolytic.
- Streptococcuseosin methylene blue (EMB), which is differential for lactose and sucrose fermentation.
Is EMB selective or differential?
Eosin methylene blue agar (EMB) is a selective and differential medium used to isolate fecal coliforms. Eosin Y and methylene blue are pH indicator dyes which combine to form a dark purple precipitate at low pH; they also serve to inhibit the growth of most Gram positive organisms.
How are MSA and Mac both selective and differential?
The MacConkey’s and Mannitol Salt described above are both selective and differential bacterial growth media. metabolize the sugar lactose) to grow in pink colonies, whereas Gram-negative non-lactose fermenting bacteria will grow in colorless colonies. This medium only grows salt-loving bacteria (so it is selective).
Is Thayer Martin Agar selective or differential?
Thayer-Martin agar is a selective medium used for the isolation of gonococci (Neisseria gonorrheae) from specimens containing a mixed flora of bacteria and/or fungi e.g. urogenital specimen. Modified Thayer-Martin (MTM) agar is a GC agar base containing vancomycin, colistin, nystatin, and trimethoprim lactate (VCNT).
Is TSA media selective or differential?
Tryptic Soy Agar (TSA): a general purpose, non-selective, non-differential, supportive medium that supports growth of all microorganisms that do not require special nutrients. Culture specimens may contain many different microorganisms.
Which is a selective and differential culture medium?
MacConkey Agar (MAC) MAC a selective and differential medium for the isolation of Gram-negative bacilli, including coliforms and enteric pathogens. This medium was one of the earliest culture media for the cultivation and identification of enteric organisms and is also used in the isolation of pathogens from foods and coliforms in water samples.
How are selective and differential media used in microbiology?
Microbiologists employ a seemingly unending variety of selective and differential media, alone or in combination, to study specific microbes – especially those of economic or medical importance. In this exercise on four types of selective and/or differential media will be examined.
Why is Hektoen agar used as a differential media?
Hektoen Enteric (HE) Agar HE agar is a selective and differential medium used for the isolation and differentiation of Gram-negative enteric pathogens, i.e., disease-causing microbes typically found in the intestinal tract of humans and other animals. This medium was originally to help increase the recovery of Salmonella and Shigella species.
How are the components of differnt media used?
To help resolve this issue, the components of differnt media are sometimes adjusted to enhance the growth of particular organisms or, alternatively, to retard the growth of unwanted microbes.