Microbiology Tests

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Questions and Answers

What is the purpose of the Simmons Citrate Test?

To determine if bacteria can use citrate as its sole carbon source (correct)

To identify if bacteria can hydrolyze starch using enzymes

To detect the ability of bacteria to produce gelatinase

To determine if bacteria can synthesize caseinase enzyme

What does the oxidase test detect?

The presence of nitrate in a sample

The ability of bacteria to ferment glucose

The presence of the cytochrome c oxidase enzyme (correct)

The ability of bacteria to reduce nitrate to nitrite

What is the indicator used in the Urease Test?

Phenol red (correct)

Olive oil

Spirit blue dye

Iodine

What is the purpose of the nitrate reduction test?

To test the ability of bacteria to reduce nitrate to nitrite or further compounds Signup and view all the answers

What is the purpose of the Casein Hydrolysis Test?

To determine if bacteria can synthesize caseinase enzyme Signup and view all the answers

What is the indicator used in the ferment glucose test?

Phenol red Signup and view all the answers

What is the reagent used in the Starch Hydrolysis Test?

Iodine Signup and view all the answers

What is the purpose of the Ferment lactose test?

To test the ability of bacteria to ferment lactose as a carbon source Signup and view all the answers

What is the purpose of the Gel Deep Test?

To detect the ability of bacteria to produce gelatinase Signup and view all the answers

What is the reagent used in the Spirit Blue Lipase Test?

Olive oil and spirit blue dye Signup and view all the answers

What is the purpose of the Methy Red Test / VP Test?

To test for mixed acid fermentation that utilizes glucose Signup and view all the answers

What is the purpose of the Catalase Test?

To identify bacteria that produce the catalase enzyme Signup and view all the answers

What is the purpose of the Kligler Iron Test?

To detect the production of acid from fermented carbohydrates and gas production Signup and view all the answers

What is the purpose of the MacConkey Agar Test?

To isolate gram negative bacteria and differentiate them based on lactose fermentation Signup and view all the answers

What is the purpose of the Phenylalanine Agar Test / Simmons?

To determine the ability of a bacteria to oxidative deamination the amino acid l-phenylalanine Signup and view all the answers

What is the result of a positive oxidase test?

A blue color change Signup and view all the answers

Study Notes

Enzyme Detection Tests

Oxidase test detects cytochrome c oxidase enzyme using tetra-methyl-p-phenylenediamine dihydrochloride, with a positive result indicated by a blue color.
Catalase test identifies bacteria that produce the catalase enzyme, using hydrogen peroxide, with a positive result indicated by a bubble reaction.

Metabolic Activity Tests

Nitrate reduction test determines a bacterium's ability to reduce nitrate to nitrite or further compounds, using sulfanilic acid and naphthylamine as reagents, with a positive result indicated by a red color.
Ferment glucose test evaluates an organism's ability to ferment glucose and produce gaseous products, using phenol red as a pH indicator, with a positive result indicated by a yellow or orange color.
Ferment lactose test determines a bacterium's ability to ferment lactose as a carbon source, using phenol red as a pH indicator, with a positive result indicated by a yellow or orange color.
Fermentation mannitol test evaluates a bacterium's ability to ferment mannitol as a carbon source, using phenol red as a pH indicator, with a positive result indicated by a yellow or orange color.
Methyl red (MR) test/Voges-Proskauer (VP) test detects mixed acid fermentation and the production of butanediol, using methyl red dye, with a positive result indicated by a red color.

Amino Acid Metabolism Tests

Phenylalanine agar test (Simmons test) determines a bacterium's ability to oxidatively deaminate l-phenylalanine to phenylpyruvic acid, using ferric chloride and hydrochloric acid, with a positive result indicated by a green color.

Carbon Source Utilization Tests

Simmons citrate test determines a bacterium's ability to use citrate as its sole carbon source, with a positive result indicated by a blue color.
Kligler iron test detects the production of acid from fermented carbohydrates and gas production, using phenol, with a positive result indicated by a yellow color, black sulfur reduction, and cracks or lifting indicating gas production.

Lipase and Protein Hydrolysis Tests

Spirit blue lipase test detects lipase enzyme production, using olive oil and spirit blue dye, with a positive result indicated by a yellow clearing of the zone.
Starch hydrolysis test determines a bacterium's ability to hydrolyze starch using enzymes, using iodine, with a positive result indicated by a red color with iodine overgrowth of the zone.
Casein hydrolysis test determines a bacterium's ability to synthesize caseinase enzyme, with a positive result indicated by clearing of the zone.
Gel deep test detects the ability to produce gelatinase, with a positive result indicated by a liquid medium.

Urea Hydrolysis Test

Urease test determines a bacterium's ability to hydrolyze urea using the urease enzyme, using phenol red, with a positive result indicated by a pink color.

Isolation and Differentiation Tests

MacConkey agar test isolates gram-negative bacteria and differentiates them based on lactose fermentation, using crystal violet, bile salts, lactose, and neutral red.

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Description

This quiz covers various tests used in microbiology to identify and characterize microorganisms, including oxidase test, nitrate reduction test, and ferment glucose test.