Topic 18: Biochemical Tests Review

stable acid

Red /pink after methyl red: pos for ________ production.

addition of iodine

Clearing after ________: pos for amylase and starch hydrolysis.

Solid medium

________: neg for gelatinase.

Liquid medium

________: pos for gelatinase.

Thick strong growth

gram neg organism

No growth

no gram neg organism

Colorful (pink, black, purple, metallic green) growth

lactose fermentation

No colorful growht

no lactose fermentation

Opaque growth

gram pos

Transparent/Weak/No growth

not gram pos

Aerobic tube yellow & anaerobic tube green

pos for glucose oxidation only

Aerobic tube & anaerobic tube yellow

pos for glucose oxidation & fermentation

Aerobic tube green & anaerobic tube green

neg for glucose oxidation and fermentation

Clearing after addition of iodine

pos for amylase and starch hydrolysis

No clearing after addition of iodine

neg for amylase and starch hydrolysis

Yellow color

pos for fermentation

Red/Pink color

neg for fermentation and pos for pepone

Bubbles in Durham tube

gas production

No bubbles in Durham tube

no gas production

True fermentation

acid and gas production

Fermentation

acid production

No fermentation

no acid or gas production

Liquid medium

pos for gelatinase

Solid medium

neg for gelatinase

Fuchsia

pos for urease

Orange/yellow/no color

neg for urease

Black color

pos for H2S

No color change

neg for H2S

purple

pos for ornithine decarboxylase

yellow

neg for ornithine decarboxylase

red after kovacs reagent

pos for indole

no colar change after kovacs reagent

neg for indole

Forrest green color

pos

No color change

neg

Red/pink color after adding reagents A & B

pos (reduced to nitrate)

No color change after A, B, & Zinc

pos (reduced to nitrous oxide or nitrogen gas)

Red after A, B, & Zinc

neg (nitrate never reduced)

strip turns purple

pos

no color change

neg

Bubble

pos

No bubbles

neg

red/purple after kovacs

pos for indole and tryptophanase

no color change

neg for indole and tryptophanse

Red/pink after methyl red

pos for stable acid production

Yellow/orange after methyl red

neg for stable acid production

Red

post for acetoin production

gray/brown

neg for acetoin production

Blue

pos

Green

neg

What does it mean when strip does not change color in oxidase tset?

organism does not have cytochrome c

organism does not have cytochrome c

strict aerobe

Is catalase test selective or differential?

differential

What is catalase test differential for?

production of catalase

What does catalase do?

breaks down hydrogen peroxide into water and oxygen gas

What is a byproduct of aerobic respiration?

hydrogen peroxide

What does bubble mean in catalase test?

catalase is present

What does no bubbles mean in catalase test?

no catalase is present

What are IMViC tests used for?

identifying enterics

What are characterisitics of enterics?

faculative anaerobes, gram negative, non-endospore forming, bacilli, live in large intestine

All four of the IMViC tests are selective or differential?

differential

What does the indole test for?

production of endoenzyme tryptophanase and production of indole

What does it mean if there is a red/purple color after kovac's reagents in indole test?

organisms has indole and tryptophanase

What does it mean if there is no color change after kovac's reagent in indole test?

organism does not have indole or tryptophanse

What does methyl red test for?

production of stable acid from glucose

What does a red/pink color mean after adding methyl red in methyl red test?

organism is positive for stable acid production

What does it mean if there is a yellow/orange color after adding methyl red in methyl red test?

organism is negative for stable acid production

What does voges-proskauer test for?

production of acetoin (unstable acid production)

What is does in VP test after incubation?

VP 1 and VP 2 reagents added and cap is left off for ~30 min

What does a red color change mean in VP test?

organism does acetoin production

What does a gray/brown color change mean in VP test?

organism does not do acetoin production

What does citrate utilization test for?

if organism can use citrate as sole carbon source and produce citrase

What is pH indicator of citrate utilization test?

bromthymol blue

What does blue color change mean in citrate utilization test?

organism does use citrate and produces citrase

What does green color change mean in citrate utilization test?

organism does not use citrate or produce citrase