Question: Is Nutrient Agar Selective Or Differential?

Is chocolate agar selective or differential?

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

Journal of Clinical Microbiology..

Is tryptic soy agar selective or differential?

Tryptic Soy Agar (TSA): is a rich, undefined medium containing products of an enzymatic digest of protein and soy product. Organisms that require vitamins or other growth factors are able to grow on TSA. Eosin Methylene Blue (EMB) Agar: is a selective AND a differential medium.

Is DNase 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. Methyl green is a cation which binds to the negatively-charged DNA.

Why is blood agar a differential medium?

Blood agar is a differential medium that distinguishes bacterial species by their ability to break down red blood cells. The ability to break down the cells will cause a change in the color of the blood agar. Some media are both differential and selective.

What type of bacteria grow on blood agar?

Blood Agar is used to grow a wide range of pathogens particularly those that are more difficult to grow such as Haemophilus influenzae, Streptococcus pneumoniae and Neisseria species. It is also required to detect and differentiate haemolytic bacteria, especially Streptococcus species.

Why is mannitol salt agar both selective and differential?

Mannitol salt agar or MSA is a commonly used selective and differential growth medium in microbiology. It encourages the growth of a group of certain bacteria while inhibiting the growth of others. … If an organism can ferment mannitol, an acidic byproduct is formed that causes the phenol red in the agar to turn yellow.

What does E coli look like on MacConkey Agar?

coli was made based on its characteristic morphology colony on the selective medium MacConkey agar. Rapid lactose fermenting colonies of E. coli appear dry, donut shaped and dark pink in color and are surrounded with dark pink area of precipitated bile salts.

What is the difference between selective and differential agar?

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.

Can a medium be both selective and differential?

Selective and differential media can be combined and play an important role in the identification of bacteria by biochemical methods. Another commonly used medium that is both selective and differential is eosin-methylene blue (EMB) agar. … Therefore, EMB is selective for gram-negatives.

Is chocolate agar a selective medium?

Chocolate Agar supplemented with bacitracin is a selective medium used to improve the primary isolation of H. influenzae from specimens containing a mixed flora of bacteria and/or fungi.

Why EMB has both selective and differential properties?

Eosin Methylene Blue (or EMB) Agar is a Selective & Differential Medium. The selective and differential aspects are due to the dyes Eosin Y and Methylene Blue, and the sugars lactose and sucrose in the medium. It is Selective because it encourages some bacteria to grow while inhibiting others.

Is nutrient agar a differential?

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

What bacteria does not grow on blood agar?

Blood agar is an enriched, bacterial growth medium. Fastidious organisms, such as streptococci, do not grow well on ordinary growth media. Blood agar is a type of growth medium (trypticase soy agar enriched with 5% sheep blood) that encourages the growth of bacteria, such as streptococci, that otherwise wouldn’t grow.

Why is MacConkey agar selective as well as differential quizlet?

Why is MacConkey agar selective as well as differential? It’s selective to gram negative enteric bacteria because it contains bile salts, which inhibit most gram positive bacteria. It also contains lactose, which differentiates between gram negative lactose fermenter and gram negative non-fermenters.

What types of bacteria grow on nutrient agar?

Nutrient agar provides these resources for many types of microbes, from fungi like yeast and mold to common bacteria such as Streptococcus and Staphylococcus.

Is MacConkey selective or 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.

What is an example of selective media?

Selective media contain ingredients that inhibit the growth of some organisms but allow others to grow. 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’s the difference between blood agar and chocolate agar?

Chocolate Agar (CAP) is the lysed blood agar. The name is itself derived from the fact that red blood cell (RBC) lysis gives the medium a chocolate-brown color. … The composition of chocolate agar and the Blood Agar is the same and the only difference is while preparing chocolate agar, the red blood cells are lysed.

What is differential media used for?

Differential media are bacteriological growth media that contain specific ingredients to allow one to distinguish selected species or categories of bacteria by visual observation. Differential Media are used to distinguish between closely related organisms or groups of organisms.

Why is MacConkey agar used for E coli?

Sorbitol MacConkey agar is a variant of traditional MacConkey agar used in the detection of E. coli O157:H7. … This is important because gut bacteria, such as Escherichia coli, can typically ferment lactose, while important gut pathogens, such as Salmonella enterica and most shigellas are unable to ferment lactose.

What bacteria can grow on MacConkey Agar?

MacConkey agar is an indicator, a selective and differential culture medium for bacteria designed to selectively isolate Gram-negative and enteric (normally found in the intestinal tract) bacilli and differentiate them based on lactose fermentation.