What is the purpose of phenylethyl alcohol agar?

Phenylethyl Alcohol Agar Protocol Phenylethyl alcohol (PEA) agar allows growth of gram-positive organisms, particularly cocci, while inhibiting most gram-negative bacteria and fungi.

What bacteria does phenylethyl alcohol agar select for?

Phenylethyl Alcohol Agar is a selective medium used for the isolation of gram-positive organisms such as Staphylococci and Streptococci.

How do you interpret phenylethyl alcohol agar?

Interpretation of results After proper incubation growth of bacteria will appear as colonies on the surface of agar plates. Gram-positive bacteria demonstrate good growth while most gram-negative bacteria do not grow or are partially inhibited.

What type of media is phenylethyl alcohol agar selective and/or differential )?

Phenylethyl Alcohol Blood Agar (PEA) is an enriched selective medium used for the inhibition of facultative gram-negative rods and to inhibit the swarming of certain Clostridium species and Proteus species from clinical specimens.

What is TSA in microbiology?

INTENDED USE. Remel Tryptic Soy Agar (TSA) is a solid medium recommended for use in qualitative procedures for the isolation and cultivation of a wide variety of organisms. Tryptic Soy Agar slants may be used to cultivate, store, and ship bacterial cultures.

What type of bacteria does PA agar inhibit?

PEA agar is a selective medium that is used for the isolation of gram- positive Staphylococcus species andStreptococcus species from clinical specimens or specimens that contain mixtures of bacterial flora (2). Typically PEA agar is used to inhibit the common contaminants such as Escherichia coli and Proteus species.

What microbes are selected for growth in MSA?

It contains a high concentration (about 7.5–10%) of salt (NaCl) which is inhibitory to most bacteria – making MSA selective against most Gram-negative and selective for some Gram-positive bacteria (Staphylococcus, Enterococcus and Micrococcaceae) that tolerate high salt concentrations.

Is phenylethyl alcohol agar a defined or undefined medium?

Phenylethyl Alchohol Agar is an undefined selective medium that encourages growth of Gram positive organisms and inhibits growth of most gram negatvie organisms.

What type of media is TSA?

EXAMPLES OF MEDIA USED IN THE LAB: Tryptic Soy Agar (TSA): a general purpose, non-selective, non-differential, supportive medium that supports growth of all microorganisms that do not require special nutrients.

How does phenylethyl alcohol agar plates inhibit growth of gram-negative organisms?

Phenylethyl alcohol agar (PEA) is a selective medium used to cultivate Gram positive organisms. The active ingredient, phenylethyl alcohol, inhibits or markedly reduces growth of Gram negative organisms by interfering with DNA synthesis. PEA also prevents Proteus species from swarming across the surface of the agar.

What is the selective agent in MSA?

Mannitol Salt Agar (MSA) contains mannitol (a sugar) and a high level of salt that limits the growth of many organisms. It is a clear pink colour and contains a pH inidcator that will turn yellow when acidic. In MSA, mannitol is. the selective agent. the differential agent.

What is the purpose of mannitol fermentation test?

The purpose is to see if the microbe can ferment the carbohydrate (sugar) maltose as a carbon source.

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 is the difference between a defined and undefined media?

A Defined medium is a relatively simple medium that is made up of specific chemicals at known concentrations. An Undefined medium is composed of mixtures of yeast cell extracts or enzymatic digests of protein; the exact amount and kinds of nutrients present in the medium are not known.

Is TSA differential or selective?

Tryptic Soy Agar (TSA): a general purpose, non-selective, non-differential, supportive medium that supports growth of all microorganisms that do not require special nutrients.

What kind of bacteria grows on TSA plate?

Trypticase Soy Agar (TSA), called Soybean-Casein Digest Agar Medium by the United States Pharmacopeia is a general-purpose nonselective growth medium that supports the growth of most Gram bacteria. -negative and non-fastidious Gram-positive as well as many yeasts and moulds.

Is PDA selective or differential?

Principle of Potato Dextrose Agar (PDA) Chloramphenicol acts as a selective agent to inhibit bacterial overgrowth of competing microorganisms from mixed specimens, while permitting the selective isolation of fungi.