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Media-Selective and Differential Traits

Explain how one media can identify both the selective and differential nature of the organism. Each one identifies different properties of the organism growing on the agar.

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Hello! Welcome to BrainMass. Let's get to it, shall we?

Ok, your question involves two different types of media: selective and differential. Let's start from the beginning.

Media (or a culture medium) is a material prepared for the growth of microorganisms in a laboratory setting. Some bacterial species (or other microorganisms, for that matter), grow very, very well on most any culture medium, while others require specific nutrients and environments to reproduce and grow. Media are constantly being developed and revised to both support the growth of a wider and wider variety of microorganisms, and to isolate and identify specific bacteria that are inoculated into the medium.

Since media are commonly used for the growth of bacteria, I will use bacteria as examples for the remainder of this post.

It is often necessary in a laboratory setting to detect the presence of specific bacteria in a sample. This task may be accomplished using selective and differential media.

Selective media are designed to suppress the growth of unwanted bacteria, while allowing for the growth of desired organisms. This is generally accomplished by adding a specific ingredient to the medium which inhibits growth of a type of bacterium. For example, Brucella sp. are slow growing organisms which are often outcompeted in mixed laboratory cultures. In order to ...

Solution Summary

Media-selective and differential traits are exemplified in 800 words. Please refer to the attached file for example of S. aureus and S. epidermidis on an MSA plate.