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Bacte LAB > Enterobacteriaceae Biochem > Flashcards

Enterobacteriaceae Biochem Flashcards

1
Q

OXIDASE TEST(Kovac’s
Method)
To determine the presence of bacterial_______ using the oxidation of the substrate_______ to indophenol, a dark purple-colored end product

A

cytochrome C oxidase

1% tetramethyl -para-phenylenediamine dihydrochloride

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2
Q

Oxidase

• PRINCIPLE:
1% TMPDD
Oxidase Reagent (Aromatic amines)

Cytochrome C oxidase

A

INDOPHENOL
(Colored compound - DARK PURPLE)

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3
Q

Oxidase REAGENTS:

A

• PADAM (dimethyl compound) Pink - Black = para-aminodimethyl aniline monohydrochloride

TMPDD = 1% tetramethyl-para-phenylenediamine dihydrochloride

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4
Q

Oxidase

Colorless → Blue or Dark Purple____sec
_______- delayed
No color change after_____ - negative

A

5-10 seconds

10-60 seconds

60 seconds

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5
Q

Oxidase

QUALITY CONTROL:
Positive:
Negative:

A

Pseudomonas aeruginosa

Escherichia coli

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6
Q

Common carbohydrates used in the media:

A

~ Glucose - monosaccharide
• Lactose - disaccharide
• Sucrose - disaccharide

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7
Q

Carbohydrate Fermentation
2 Enzymes used in Lactose Degradation

A

• B-galactoside permease (Lactose permease)
• B-galactosidase

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8
Q
  • LF:
  • NLF:
    • LLF:
A

possess both of the enzymes

do not possess both of the enzymes

possess only B-galactosidase

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9
Q

Carbohydrate Fermentation

Indicator
Color change depending on pH

Bromcresol purple

Andrade’s fuchsin

Phenol red

A

Purple (alk) yellow (acid)

Pale yellow (alk) reddish pink (acid)

Red (alk) yellow (acid)

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10
Q

CHO fermentation using Broth
positive carbohydrate fermentation media

Media used:

A

Phenol red Broth: contains peptone, phenol red (a pH indicator), a Durham tube, and one carbohydrate (glucose,
lactose, or sucrose)

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11
Q

СНО:
• TSI -
• KIA -

A

glucose (0.1% or 1 part), lactose (1% or 10 parts), and sucrose (1% or 10 parts)

glucose (0.1% or 1 part), lactose (1% or 10 parts)

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12
Q

CULTURE MEDIA
COMPOSITION
TSI (Triple Sugar Iron)

KIA (Kligler’s Iron Agar)

RDA (Russel’s Double Agar)

A

glucose, lactose, sucrose, iron

glucose, lactose, iron

glucose, lactose

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13
Q

Triple Sugar Iron
TSI

pH indicator

A

phenol red

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14
Q

TSI

H2S indicator
: forms H2S upon interaction with the organisms

: binds to H2s = forming a black
precipitate

A

• Sodium thiosulfate

• Ferrous sulfate

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15
Q

Triple Sugar Iron

• Glucose/Sucrose/Lactose not fermented
• This reaction is typical among the Non-Fermentative organisms

Ex..

A

K/K

• P. aeruginosa

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16
Q

Triple Sugar Iron

• Glucose/Sucrose/Lactose not fermented
• This reaction is typical among the Non-Fermentative organisms

Ex..

A

K/K

• P. aeruginosa

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17
Q

Triple Sugar Iron
TSI

• Glucose fermented
• Lactose/sucrose not fermenters

With blackening

Ex..

A

K/A, H2S (+)

• Salmonella spp.
• Proteus
• Arizonae
• Citrobacter
• Edwardsiella

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18
Q

Triple Sugar Iron

• Glucose fermented
• Lactose/Sucrose not fermented

Ex…

A

K/A, H2S (-)

• Yersinia
• Escherichia coli
• Serratia
• Shigella
• Providencia
• Morganella
• Citrobacter

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19
Q

Triple Sugar Iron
TSI

• Glucose fermented
• Lactose/Sucrose fermented

With blackening

Ex..

A

A/ A H2S (+)

Salmonella
Proteus
Citrobacter

20
Q

Triple Sugar Iron
TSI

• All sugars are fermented

A

A/A, H2S (-)

• Escherichia coli
• Klebsiella
• Enterobacter
• Serratia

21
Q

ONPG

A

O-nitrophenyl-beta-D-galactopyranoside

22
Q

• Determines the presence of late or slow lactose fermenting strains

A

ONPG (O-nitrophenyl-beta-D-galactopyranoside)

23
Q
  • structurally similar with lactose
    -Can enter the bacterial cell without the Lactose permease
A

• ONG molecule

24
Q

-In the presence of Beta-galactosidase, ONPG (colorless), is converted into_____ and _____ which is a yellow chromogen

A

galactose and o-nitrophenyl

25
Q

KOVAC’S METHOD
• Medium:
•
• Indole indicator:
•
• Positive Result:
• Development of a

A

Tryptone broth or trypticase broth

Kovac’s reagent (p-dimethylaminobenzal-dehyde)

pink to deep red color

26
Q

EHRLICH’S METHOD
• Medium:
• Tryptone broth or trypticase broth
• With ______
• Indole indicator:
*______
• Positive Result:
•_____

A

Xylene or Ether

Ehrlich’s reagent (p-dimethylaminobenzal-dehyde)

Brilliant red ring between the solvent and the medium.

27
Q

• This is a rapid method for the detection of indole

Positive Result:

A

SPOT INDOLE TEST

blue or blue green color

28
Q

• Principle
‹ Some organisms produce large amounts of acid from dextrose while others produce less.

This test is based upon the final hydrogen ion concentration (acidity) reached by a culture.

The test will be positive if the pH is 4.5 or lower, and negative if above pH 4.5.

A

Methyl Red Test (Mixed Acid Fermentation Pathway)

29
Q

MR

• Medium:
•
• pH indicator:
*
• Results
• Positive:
• Negative:

A

MR-VP or the Clark and Lubb’s dextrose broth

Methyl Red

Red color (pH 4.5 or below)

Yellow color (above 4.5)

30
Q

• Principle
• Some bacteria have the ability to produce acetoin (acetylmethylcarbinol) from glucose.

In an alkaline pH, acetoin is oxidized to diacetyl (dimethylcarbinol), which reacts with guanidine compounds present in the broth to give a red-colored complex.

A

Voges-Proskauer Test (Butylene glycol pathway)

31
Q

Voges-Proskauer Test (Butylene glycol pathway)

Reagents:
•______ in 95% ethyl alcohol
•_____ in distilled H2O (provides alkalinity)
‹______ in distilled H20 (prevents false negative results)

A

5% alpha-naphthol

40% KOH

0.5% creatine

32
Q

• Principle
• Some organisms can utilize CITRATE as their sole source of carbon producing acetate and other alkaline carbonate end products in the process.

A

CITRATE

33
Q

Citrate test

Medium

A

Simmons citrate agar
Christensen citrate medium

34
Q

Citrate

pH indicator:
•

A

Bromthymol blue

35
Q

Citrate

• acid: pH 6 ()
‹ uninoculated: pH 6.9 ()
• alkaline: pH 7.6 ()

A

Yellow

Green

Blue

36
Q

Citrate

Results:
• Positive:
-Growth with an intense prussian blue color on the slant
-Ex.

A

Enterobacter and Klebsiella

37
Q

Citrate

~ Negative:
-Absence of growth and no color change in the medium (remains green)
-Ex.

A

Escherichia coli

38
Q

++–

IMViC

A

E. coli
Morganella
Proteus
Edwardsiella

39
Q

IMViC

–++

A

Klebsiella
Enterobacter
Serratia
Hafnia

40
Q

IMViC
-+-+

-+-+

A

Salmonella
Arizonae
Citrobacter

41
Q

Principle:
• This is based upon the ability of some bacteria to hydrolyze Urea into Ammonia, water and CO2 by means of the enzyme, Urease.

If urea is split to form ammonia, the medium becomes alkaline and the indicator turns from Yellow to Pink

A

Urease

42
Q

Urease

• Medium:
‹ _____ or _____

Original color:____
• pH indicator:
•______
• Positive result:
Color yellow changes to____

A

Christensen’s Urea Agar tubes, or Stuart Urea broth

yellow

Phenol red

PINK

43
Q

Urease

  • Useful in the identification of RAPID UREASE PRODUCERS (w/in 2-4 hours)

• WEAK UREASE PRODUCERS within 4 hours

A
  • Proteus, Providencia, Morganella (PPM)
  • Citrobacter, Klebsiella, Enterobacter, Yersinia, and Serratia (CKEYS)
44
Q

Motility test
• Medium:
* SIM medium or any semisolid motility medium

-Can be added with______ to aide visualization (optional)

A

SIM

1% triphenyltetrazolium chloride

45
Q

SIM

• Results:
v (+) motile organisms spread out/ grow away from inoculation line

v (-) nonmotile organisms grow only along the stab line

A
46
Q

SIM

Nonmotile @ 37C:

A

Shigella, Klebsiella, Yersinia

Bacte LAB (35 decks)

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