Phenylethyl alcohol agar (PEA) is a selective medium that permits the growth of Gram-positive cocci while inhibiting most Gram-negative organisms.
The active ingredient, phenyl ethyl alcohol, alters the membrane permeability of Gram-negative bacteria, allowing the influx of otherwise blocked molecules.
PEA inhibits or markedly reduces the growth of Gram-negative organisms by interfering with DNA synthesis. PEA also prevents Proteus species from swarming across the surface of the agar.
Selective media are used for the growth of only selected microorganisms. PEA is a selective medium used to cultivate Gram-positive organisms, particularly cocci, from a sample containing a mixture of pathogens.
PEA is used to inhibit common contaminants such as Escherichia coli and Proteus species. PEA may be prepared with or without a 5% sheep blood supplement, which is added to the base medium to enhance the growth of anaerobic bacteria.
What Is The Purpose Of Phenylethyl Alcohol Agar?
Phenylethyl alcohol agar (PEA) is a selective growth medium used in microbiology to isolate gram-positive bacteria from mixed cultures.
The purpose of PEA is to inhibit the growth of gram-negative bacteria while allowing the growth of gram-positive bacteria. PEA contains phenyl ethyl alcohol, which is toxic to gram-negative bacteria but not to gram-positive bacteria.
The agar also contains nutrients that support the growth of gram-positive bacteria. PEA is commonly used to isolate Staphylococcus and Streptococcus species from clinical samples.
How Does Phenylethyl Alcohol Agar Work?
Phenylethyl alcohol (PEA) agar is a selective medium used to cultivate gram-positive organisms, particularly cocci while inhibiting most gram-negative bacteria and fungi.
The active ingredient in PEA agar is phenyl ethyl alcohol, which inhibits or markedly reduces the growth of gram-negative organisms by interfering with DNA synthesis.
PEA agar is used for the isolation of gram-positive Staphylococcus species and Streptococcus species from clinical specimens or specimens that contain mixtures of bacterial flora.
It is typically used to inhibit common contaminants such as Escherichia coli and Proteus species. PEA agar also prevents Proteus species from swarming across the surface of the agar.
What Type Of Organisms Can Grow On Phenylethyl Alcohol Agar?
Phenylethyl alcohol (PEA) agar is a selective medium that allows the growth of gram-positive organisms, particularly cocci while inhibiting most gram-negative bacteria and fungi.
PEA agar is used for the isolation of gram-positive Staphylococcus species and Streptococcus species from clinical specimens or specimens that contain mixtures of bacterial flora. PEA agar is also used to inhibit common contaminants such as Escherichia coli and Proteus species.
Therefore, only gram-positive bacteria can grow on PEA agar, while gram-negative bacteria and fungi are inhibited.
Gram-positive bacteria are those that retain the crystal violet stain in the Gram staining procedure, while gram-negative bacteria do not. Examples of gram-positive bacteria that can grow on PEA agar include Staphylococcus and Streptococcus species.
What Is The Active Ingredient In Phenylethyl Alcohol Agar?
The active ingredient in Phenylethyl Alcohol (PEA) agar is phenyl ethyl alcohol. PEA agar is a selective medium used to cultivate gram-positive organisms, particularly cocci, from a sample containing a mixture of pathogens.
The active ingredient, phenyl ethyl alcohol, inhibits or markedly reduces the growth of gram-negative organisms by interfering with DNA synthesis. PEA agar also prevents Proteus species from swarming across the surface of the agar.
PEA agar is a selective medium that is used for the isolation of gram-positive Staphylococcus species and Streptococcus species from clinical specimens or specimens that contain mixtures of bacterial flora.
PEA agar allows the growth of gram-positive organisms, particularly cocci while inhibiting most gram-negative bacteria and fungi. PEA agar is typically used to inhibit common contaminants such as Escherichia coli and Proteus species.
The composition of PEA agar includes phenyl ethyl alcohol, casein peptone, yeast extract, sodium chloride, and agar.
Sodium chloride supplies essential electrolytes and maintains osmotic equilibrium, while sheep blood, added to the prepared medium, provides enrichment by supplying essential growth factors. The final pH of PEA agar at 25°C is 7.3 ± 0.2. PEA agar may be prepared with or without a 5% sheep blood supplement.
What Is The Preparation Process For Phenylethyl Alcohol Agar?
Phenylethyl alcohol agar (PEA) is a selective medium used to cultivate Gram-positive organisms, particularly cocci, from a sample containing a mixture of pathogens. The preparation process for PEA is similar across different sources.
First, the ingredients are suspended in one liter of distilled water and mixed thoroughly. The mixture is then heated with frequent agitation and boil for one minute to dissolve completely.
The medium is then autoclaved for 15 minutes at 121°C and 15 lb/in^2. After autoclaving, the medium is cooled to about 45°C. Finally, 5% sterile defibrinated sheep blood is aseptically added and mixed well.
The final pH of the medium should be 7.3 ± 0.2 at 25°C. PEA may be prepared with or without a 5% sheep blood supplement. Five percent sheep blood is added to the base medium to enhance the growth of anaerobic bacteria.
For the preparation of blood agar, 5% v/v sterile defibrinated blood is added to sterile molten agar that is cooled to 45°C. The mixture is then mixed well and poured into sterile petri plates.
PEA agar is used to inhibit common contaminants such as Escherichia coli and Proteus species. It allows the growth of gram-positive Staphylococcus species and Streptococcus species from clinical specimens or specimens that contain mixtures of bacterial flora.
