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EMB (Eosin Methylene Blue) Agar
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selective for: gram-negative bacteria
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growth of gram-positive bacteria (e.g.: Staphylococcus aureus in the image below) is inhibited by the eosin & methylene blue dyes in the media
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differential for: lactose fermentation
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gram-negative Enterobacteria Escherichia coli and Enterobacter aerogenes ferment lactose
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E. coli produces colonies with a characteristic green metallic sheen on EMB agar
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E. aerogenes produces pink colonies often with a central dark purple dot (fish eye colonies) on EMB agar
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gram-negative bacteria Proteus vulgaris and Salmonella typhimurium grow on EMB agar, but do not ferment lactose
MacConkey's Agar
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selective for: gram-negative bacteria
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growth of gram-positive bacteria (e.g.: Staphylococcus aureus in the image below) is inhibited by the crystal violet dye and bile salts in the media
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differential for: lactose fermentation
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neutral red pH indicator turns red in the presence of acid by-products of lactose fermentation
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gram-negative Enterobacteria Escherichia coli and Enterobacter aerogenes ferment lactose
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E. coli produces pink to red colonies often with a reddish bile precipitate surrounding colonies on MacConkey's agar
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E. aerogenes produces pink to red mucoid colonies on MacConkey's agar
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gram-negative bacteria Proteus vulgaris and Salmonella typhimurium grow on MacConkey's agar, but do not ferment lactose (media appears yellow to light pink in color & colonies are colorless; swarming of Proteus is inhibited)
MSA (Mannitol Salt Agar)
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selective for: gram-positive Staphylococci bacteria
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7% salt in the medium inhibits the growth of most gram-positive and gram-negative bacteria
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differential for: mannitol fermentation
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phenol red pH indicator turns yellow in the presence of acid by-products of mannitol fermentation
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Staphylococcus aureus ferments mannitol
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S. aureus changes the color of the medium from pink to yellow due to acid by-products of mannitol fermentation
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Staphylococcus epidermidis grows on MSA, but does not ferment mannitol (media remains light pink in color & colonies are colorless
Hemolysis with Blood Agar
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agar contains 5% sheep's blood
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differential for: hemolysis...particularly in streptococci
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based on the ability to break down hemoglobin or red blood cells, 3 groups of microorganisms can be described
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alpha-hemolysis: a green to light-brown halo is seen around the colonies; bacteria partially break down hemoglobin leaving a green pigment (biliverdin)
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beta-hemolysis: a clearing is seen around the colonies; bacteria produce a "beta-hemolysin" (streptolysin O or S), which lyses red blood cells in the medium
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gamma-hemolysis (no hemolysis): no hemolysis is observed; bacteria do not produce a hemolysin
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Is the media for oxidase test selective or differential?
media used for oxidase test is non selective media
What is the principle of selective media?
Scientists in a lab use selective media and differential media to identify or isolate organisms. Selective media allows only certain types of organisms to grow.
Is a tsa agar selective or differential?
its a selective media
Is Mueller Hinton agar is selective media?
no
How does selective media works in microbiology?
Selective media, is made up of certain nutrients that can either inhibit or enhance the growth of certain bacteria and or fungus. This is why they call it selective media, it is generally only selective for one kind of bacteria or does certain things when that bacteria or fungus is present.
Which type of culture media is best for the growth of most chemoheterotrophic organisms?
selective media
What the B subtilis selective media?
nutrient Agar
What are the selective media for isolation of thermophiles?
thermus agar
What is enrichment medium and how does it differ from differential and selective media?
Selective media is one that grows only certain microorganisms while inhibiting (or preventing) others from growing, that is to say , the media has certain chemicals that allow one organism to grow but another organism cannot grow with those ingredients in the media, thus, is selective for the organisms that can grow in that media. Therefore, most commonly grows only one type of organism. Differential media is one that distinguishes one microorganism from another, it can grow more than one microorganism, but depending on how each organism reacts to the media (like turns red) it differentiates from another microorganism. In this type of media if you are trying to distinguish between 2 types of microorganisms, both should grow but they will have different reactions to the media, and thru their visible reactions you can tell them apart (differentiate them).
Is tryptone broth differential or selective media?
differential.
Is Differential media a type of culture media?
what do you mean? I would say yes. The main types of culture media are Enriched media Differential media Selective media Characterisation media.
When would you want to use selective media?
Selective Media - Our cell membrane has a selective permeable property. This type of membranes are important when we want to allow certain sized particles to enter while restricting other sized particles to enter our cell. Selective permeable membrane is of great use in biological samples.
