What Type Of Media Is A Nutrient Agar If An Antibiotic (like Streptomycin) Is Added?


Is nutrient agar a synthetic medium?

Semi- synthetic: Culture media, the chemical components of which are partially known and partially obscure are termed as semi- synthetic culture media. Examples- Potato dextrose agar (PDA), Czapek-Dox agar, oat meal agar (OMA), corn meal agar (CMA), beef peptone agar and nutrient agar.

Is nutrient agar selective or differential?

1. Observe the growth and appearance of colonies on all plates. Notice that nutrient agar is neither a selective nor differential medium.

What is selective and differential media?

Selective media generally selects for the growth of a desired organism, stopping the growth of or altogether killing non-desired organisms. Differential media takes advantage of biochemical properties of target organisms, often leading to a visible change when growth of target organisms are present.

What is the application of selective medium?

Selective media are used for the growth of only selected microorganisms. For example, if a microorganism is resistant to a certain antibiotic, such as ampicillin or tetracycline, then that antibiotic can be added to the medium to prevent other cells, which do not possess the resistance, from growing.

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What bacteria can grow on nutrient agar?

Microorganisms need food, water and a suitable environment in order to survive and grow. Nutrient agar provides these resources for many types of microbes, from fungi like yeast and mold to common bacteria such as Streptococcus and Staphylococcus.

What type of medium is nutrient agar?

Nutrient agar is a general purpose medium supporting growth of a wide range of non-fastidious organisms. It typically contains (mass/volume): 0.5% Peptone – this provides organic nitrogen. 0.3% beef extract/yeast extract – the water-soluble content of these contribute vitamins, carbohydrates, nitrogen, and salts.

What color is E coli on nutrient agar?

coli on Nutrient Agar (NA) 1. They appear large, circular, low convex, grayish, white, moist, smooth, and opaque.

What is the difference between nutrient broth and nutrient agar?

The main difference between them is that nutrient agar contains a solidifying agent, agar powder that causes the medium to solidify in room temperature, whereas nutrient broth remains in liquid form. Example of nutrient agar in a petri dish.

Is DNase agar selective or differential?

DNase agar is a differential medium that tests the ability of an organism to produce an exoenzyme, called deoxyribonuclease or DNase, that hydrolyzes DNA. DNase agar contains nutrients for the bacteria, DNA, and methyl green as an indicator.

Which two types of media are both selective and differential?

Another commonly used medium that is both selective and differential is eosin-methylene blue (EMB) agar. EMB contains the dyes eosin and methylene blue that inhibit the growth of gram-positve bacteria. Therefore, EMB is selective for gram-negatives.

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Why MacConkey agar is selective and differential?

MacConkey agar is a selective and differentiating agar that only grows gram-negative bacterial species; it can further differentiate the gram-negative organisms based on their lactose metabolism.

Is chocolate agar selective or differential?

Chocolate agar, a differential medium for gram-positive cocci.

What organisms are inhibited from growing on 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.

What bacteria does not grow on blood agar?

Fastidious organisms, such as streptococci, do not grow well on ordinary growth media but grow on blood agar.

What are the 3 main types of microbiological culture media?

These are classified into six types: (1) Basal media, (2) Enriched media, ( 3 ) Selective (4) Indicator media, (5) Transport media, and (6) Storage media. 1. BASAL MEDIA. Basal media are those that may be used for growth ( culture ) of bacteria that do not need enrichment of the media.

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