Difference Between Selective Media And Differential Media With Examples

What Is Selective Media?

Selective media refer to a type of growth media that allows the growth of selected microorganisms in the medium. Selective media are formulated to contain ingredients that inhibit the growth of selected species or categories of bacteria while allowing other organisms to grow.  These formulations may include antibiotics which inhibit the growth of gram positive bacteria or gram negative bacteria. For example, mannitol salt agar contains a high concentration of sodium chloride that inhibits the growth of most organisms but permits staphylococci to grow.

What You Need To Know About Selective Media

• Selective media refer to a type of growth media that allows the growth of selected microorganisms in the medium.
• It is also referred to as specialized media.
• It is characterized by the growth of single organism showing different growth pattern.
• Selective media is supplemented with certain growth promoting or inhibiting substances that can be organism or species specific.
• It is more specific as it permits the growth of single microorganism in the medium.
• Does not use indicators.
• Examples of selective media include: Mannitol salt agar, tellurite media, Lowenstein-Jansen media, thiosulphate-citrate bile sucrose agar etc.

What Is Differential Media?

Differential media refer to a type of growth media that allows the differentiation of closely-related microorganisms. Owing to the presence of certain dyes or chemicals in the media, the organisms will produce characteristic changes or growth patterns that are used for identification or differentiation. 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.  Blood agar is one type of differential medium, allowing bacteria to be distinguished by the type of hemolysis produced. Some differential media are also selective i.e most standard enteric agars such as MacConkey and EMB agar for gram-negative coliforms and which differentiate lactose-fermenting and non-lactose-fermenting.

What You Need To Know About Differential Media

• Differential media refer to a type of growth media that allows the differentiation of closely-related microorganisms.
• It is also referred to as indicator media.
• It is characterized by the color change in the media as well as the bacterial colony.
• Differential media is supplemented with the indicator dyes that differentiate the bacterial isolates based on color change.
• It is less specific, as it allows closely-related microorganisms to grow in the medium.
• It does use indicators.
• Examples of differential media include: MacConkey agar, Eosin methylene blue agar, blood agar, deoxycholate citrate agar etc.

Difference Between Selective Media And Differential Media In Tabular Form