What is a selective media?

Selective media are used to select for the growth of a particular "selected" microorganism. For example, if a certain microbe is resistant to aparticular antibiotic (e.g., novobiocin), then that antibiotic can be added to the medium in order to prevent other organisms, which are not resistant, from growing.

What is the definition of selective media?

A selective medium is a medium that allows the selection of one or more types of microorganisms. These microorganisms will be the only ones able to grow on or in the medium while all the others will be inhibited.

What is an example of selective media?

Selective medium contain particular ingredients that inhibit the growth of certain microbes. An example of a selective medium is MacConkey agar. It contains bile salts and crystal violet, which interfere with the growth of many gram-positive bacteria and favor the growth of gram-negative bacteria.

What are the types of selective media?

Selective media

• Eosin methylene blue contains dyes that are toxic for Gram-positive bacteria. ...
• YM (yeast extract agar) has a low pH, deterring bacterial growth.
• MEA (malt extract agar) has a low pH, deterring bacterial growth.
• MacConkey agar is for Gram-negative bacteria.

What is selective and non selective media?

Selective media generally selects for the growth of a desired organism, stopping the growth of or altogether killing non-desired organisms. Differential media takes advantage of biochemical properties of target organisms, often leading to a visible change when growth of target organisms are present.

Is Mac selective or differential?

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.

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.

What is selective media for E coli?

An enriched lauryl sulphate-aniline blue agar medium which is selective for Escherichia coli and coliform organisms is described. From faecal samples, the medium gave higher counts of colonies producing acid from lactose than media containing bile salts.

What's the difference between selective and differential media?

The main difference between selective and differential media is that selective media are used to isolate a particular strain of microorganisms whereas differential media are used to identify and differentiate a closely-related group of microorganisms.

What is the difference between selective media and enrichment media?

Enriched media contains some component that permits the growth of specific types of bacteria because they alone can utilise the component from their environment . Selective media has a component which will inhibit or prevent the growth of certain species of bacteria and promote the growth of desired species .

Is CNA selective or differential?

CNA is a selective, differential agar medium used for isolation of gram positive bacteria in a variety of specimen types.

Is Blood agar selective?

Blood agar is a non-selective medium that can be made selective for certain pathogens by the addition of antibiotics, chemicals or dyes.

Is LB agar selective or differential?

The LB culture medium (for lysogeny broth) is a non-selective nutrient culture medium, initially used for bacterial culture. LB media have become an industry standard for the cultivation of Escherichia coli.

What does the Kirby-Bauer test assess?

What characteristic of the Kirby-Bauer test helps scientists to determine if a microorganism is susceptible to an antibiotic? B) The ability of the microorganism to degrade the agar around the antibiotic disks.

What is selective media quizlet?

What is the definition of a Selective Media? A Selective Medium is a culture medium designed to allow the growth of some kinds of organisms, but not others.

Is MSA selective or differential?

This type of medium is both selective and differential. The MSA will select for organisms such as Staphylococcus species which can live in areas of high salt concentration (plate on the left in the picture below).

What are 3 uses for selective and differential media?

A variety of selective and differential media are used in medical, diagnostic and water pollution laboratories, and in food and dairy laboratories.

What is an example of differential media?

MacConkey's Agar (MAC)

At the same time, it is a differential medium that allows for the differentiation of organisms that can ferment lactose from those that cannot. MacConkey's Agar is recommended for use in the detection and isolation of all types of dysentery, typhoid, and paratyphoid bacteria (Salmonella).

Why different media is used for isolation of different microorganisms?

Chemically defined media contain only chemically known components. Selective media favor the growth of some microorganisms while inhibiting others. Differential media help distinguish bacteria by the color of the colonies or the change in the medium.

Can a media be both selective and differential?

Some media are selective, some are differential and some are both. We will study Mannitol Salt Agar and MacConkey agar as examples. Mannitol Salt Agar (MSA) can be used to presumptively isolate and identify Staphylococci from human samples.

What is the selective media for Pseudomonas?

Cetrimide agar is a type of agar used for the selective isolation of the gram-negative bacterium, Pseudomonas aeruginosa.

What is the purpose of differential media?

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.

Why sheep blood is used in blood agar?

Sheep blood has been preffered source in the Blood agar due to the fact that sheep RBCs are most sensitive to the the hemolytic toxins released by bacterial cells thus causing hemolytic zones around the colonies over the period of time.

Is chocolate agar non selective?

BD Chocolate Agar (GC II Agar with IsoVitaleX) and BD Chocolate Agar (Blood Agar No. 2 Base) are non-selective media for the isolation and cultivation of fastidious microorganisms, especially Neisseria and Haemophilus species, from a variety of clinical specimens.

What grows MacConkey agar?

MacConkey agar is a selective and differentiating agar that only grows gram-negative bacterial species; it can further differentiate the gram-negative organisms based on their lactose metabolism.