Biochemical Tests Part 2 Flashcards

1
Q

Results for Lysine Iron Agar

A

Slant (Deamination) = Burgundy red (+); Purple (-)
Butt (Decarboxylation) = Purple (+); Yellow (-)

Purple: Deamination neg, Decarboxylation pos

*deAmination & deCarboxylation = A first sa alphabet meaning una makita from opening of tube (slant)

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2
Q

Result interpretation of LIA

A

K/K (Purple/Purple) : Decarboxylase (+)
R/A (Red-Burgundy/Yellow) : Deamination (+) w/ Glucose Fermentation
K/A (Purple/Yellow) : Decarb & Deam (-) w/ Glucose fermentation

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3
Q

What organisms presents as K/K, H2S(+) on LIA

A

Salmonella

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4
Q

What organism presents as K/A, H2S (-) on LIA

A

Shigella

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5
Q

What organism Presents as R/A, H2S (-) o LIA

A

Proteus, Providencia, Morganella (PPM)

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6
Q

Organisms reported as K/K on LIA

A

E. coli, Klebsiella, Enterobacter (EKE)
Serratia
Hafnia
Salmonella

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7
Q

Reported as K/A on LIA

A

Enterobacter cloacae
Yersinia spp
Shigella spp

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8
Q

Reported as R/A on LIA

A

Proteus, Providencia, Morganella (PPM)

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9
Q

Determines the ability of an organism to use citrate as sole carbon source and inorganic ammonium salts as sole nitrogen source

A

Citrate Utilization Test

Part of IMViC (indole, methyl red, Voges-Proskauer, and citrate), which is used to differentiate Enterobacteriaceae from other gram-negative rods

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10
Q

Media used for Citrate Utilization test

A

Simmon citrate

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11
Q

pH indicator of Citrate utilization

A

Bromthymol Blue

*SHOT tag gsm Blue (Simmon Citrate Agar, HEA, OF medium, Thiosufate Citrate Bile Sucrose Agar)

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12
Q

Positive result for Citrate Utilization Test

A

Growth in the medium w/ or w/out a change in the color of the indicator

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13
Q

Positive and Negative QC for Citrate utilization test

A

Positive QC: Serratia
Negative QC: E. coli

Enterobacter (+), Other gram neg rods (-)

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14
Q

Principle is based on the ability of some bacteria to hydrolyze urea into ammonia water and CO2, leading to alkalinity of the medium

A

Urease Test

Proteus spp. may be presumptively identified by the ability to rapidly hydrolyze urea

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15
Q

pH Indicator of Urease Test

A

Phenol Red

*TX MU C Aling Dionesia Pacqiuao (TSI, XLD, MSA, Urease, Acidimetric, Dermatophyte Test Medium: Phenol Red)

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16
Q

Medium used for Urea Test

A

Christensen Urea

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17
Q

Other name for Urease Method

A

Christensen’s Method

*Name from the medium used: Christensen Urea

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18
Q

Positive Result for Urea

A

Color change from Yellow to RED (Orange to Magenta)

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19
Q

Positive & Negative QC for Urease Test

A

Positive QC: Citrobacter
Negative QC: E. coli

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20
Q

What are the Rapid Urease positive Bacteria

A

Proteus, Providencia, Morganella (PPM)

*Other Urease (+) organism Mnemonic (PUNCH: Proteus, Providencia, Ureaplasma, Nocardia, Citrobacter, Helicobacter)

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21
Q

What are slow Urease positive organism

A

Citrobacter
Klebsiella
Enterobacter
Yersinia
Serratia

*Mnemonic C-KEYS (U have C-KEYS to my heart)

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22
Q

Measures and organism’s ability to decarboxylate/hydrolyze an amino acid to produce amine

A

Decarboxylase Test

*Differentiate decarboxylase-producing Enterobacteriaceae from other gram-negative rods

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23
Q

pH indicator of Decrboxylase test

A

Bromcrescol Purple

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24
Q

Positive result for Decarboxylase test

A

Color change from Yellow (acid) to Purple (Alkaline)

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25
Q

What are the amino acids used in Decarboxylase test and what are the products of their decarboxylation

A

Lysine > Cadaverine
Ornithine > Putrescine
Arginine > Citrulline

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26
Q

Positive QC for Decarboxylation test

A

Lysine = Klebsiella pneumoniae
Ornithine = Klebsiella obsytoca
Arginine = Klebsiella obsytoca

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27
Q

Determines the ability of anorganism to ferment a specific carbohydrate in a basal medium, w/ or w/out gas production

A

Fermentation Media

A fermentation medium consists of a basal medium containing a single carbohydrate (glucose, lactose, or sucrose) for fermentation and a color indicator of choice

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28
Q

What is used in Fermentation media that allows for differentiation of EBC’s (Enterobacterceae) from Coryneforms

Coryneforms = Corynebacterium

A

Peptone medium w/ Andrade’s acid fuchsin

Brain Heart infusion Broth w/ Bromcresol purple is used to distinguish enterococci from streptococci

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29
Q

What is used to detect gas formation in in fermentation media

A

Durham tube

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30
Q

Positive result for fermentation media

A

Indicator changes color to pink w/ or w/out Gas production

Negative result = no color change (Solution remains clear/ Pale Yellow/ Straw colored)

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31
Q

Organism that presents as Positive (Pink), with gas on Fermentation Media

A

E. coli

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32
Q

Organism that presents as Positive (Pink), without gas on fermentation media

A

Shigella

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33
Q

Organism that presents as Negative (Straw/Pale yellow/Clear) on fermentation media

A

Pseudomonas aeruginosa

Cannot ferment glucose

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34
Q

This test is used to identify organisms that produce the enzyme tryptophanase

A

Indole Test

Tryptophanase: Hydrolyzes: Tryptophan > indole + Pyruvic acid/Pyruvate + Ammonia

Test is part of IMViC

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35
Q

Reagent used for Enterobacteriaceae in Indole test

A

Kovac’s reagent

Contains para-dimethylaminobenzaldehyde (DMAB), and concentrated hydrochloric acid

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36
Q

Reagent used for other gram negative bacilli in Indole Test

A

Ehrlich’s Reagent

p-dimethylaminobenzaldehyde (DMAB) and Xylene

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37
Q

Positive result of Indole Test

A

Pink to wine colored ring

38
Q

Indole positive and negative organism using Kovac’s method

A

Positive: E. coli
Negative: K. pneumoniae

39
Q

Indole positive and negative organism using Ehrlich’s method

A

Positive: Elizabethkingia meningoseptica
Negative: CDC group EO-2

40
Q

Determines organism’s ability to produce and maintain stable acid end products from glucose fermentation

A

Methyl Red Test

pH indicator: Methyl Red
Combination test with Vogues-Proskauer

41
Q

Positive, weakly positive result and negative results for Methyl Red Test

A

Positive = Red
Weakly Positive = Red orange
Negative = Yellow

42
Q

Positive and Negative QC for Methyl Red

A

Positive QC: E. coli
Negative QC: Enterobacter

43
Q

Determines the organism’s ability to produce neutral end products from glucose fermentation

A

Voges Proskauer

44
Q

Method of Voges Proskauer used on Gram Negative Rods

A

Barritt’s Method

45
Q

Reagents Used for Barritt’s Method (Voges Proskauer)

A

Solution A: a-Naphthol
Solution B: 40% KOH

46
Q

Positive and Negative QC for Barritt’s Method (Voges Proskauer)

A

Positive QC: E. coli
Negative QC: Enterobacter aerogenes

47
Q

Method used for Streptococci (Voges Proskauer)

A

Coblentz

48
Q

Reagents for Coblentz method (Voges Proskauer)

A

Solution A: alpha-naphthol
Solution B: 40% KOH + Creatine

Barritt’s Method Reagents: Same with Coblentz but w/out Creatine on Sol B

49
Q

Positive and Negative QC for Coblentz Method (Voges Proskauer)

A

Positive QC: Streptococcus mutans
Negative QC: Streptococcus mitis

50
Q

Positive and Negative result for Voges Proskauer

A

Positive: Red
Negative: Yellow

Same as Methyl Red

51
Q

Determines an organism’s ability to reduce nitrate to nitrite

A

Nitrate Reduction Test

Detects the presence or absece of three metabolic products: gas, nitrate, and nitrite

52
Q

Reagents used for Nitrate Reduction Test

A

1st: Sulfanilic Acid & Alpha-Naphtylamide
2nd: Zinc

Sulfanilic Acid + Nitrite + alpha-naphthylamide = red color (Nitrate is reduced by organism)

Add Zinc + Nitrate = red color (Nitrate is not reduced by organism)

No Color Change = Nitrate reduced to other nitrogen compounds

53
Q

QC for Nitrate Reduction Test

A

Positive Nitrate (NO3+), no gas: E. coli
Nitrite (NO3+), gas: Pseudomonas aeruginosa
Negative: Acinetobacter spp

All members of the Enterobacteriaceae family reduce nitrate, but some members further metabolize nitrite to other compounds

54
Q

This test determines an organism’s ability to produce the enzyme: B-galactosidase

A

ONPG Test
o-Nitrophenyl-b-D-Galactopyranoside (ONPG) Test

Distinguishes late lactose fermenters from non-lactose fermenters

55
Q

Beta-galactosidase hydrolyzes ONPG to ________

A

Orthonitrophenol

56
Q

Positive Result for ONPG Test

A

Yellow

Due to Orthonitrophenol which is a yellow compound

57
Q

Positive and Negative QC for ONPG Test

A

Positive QC: E. coli
Negative QC: Salmonella typhimurium

Positive QC: Shigella sonnei (Bailey’s)
Mnemonic for Late Lactose Fermenter (Yanna Eats Half Sugar Cookies) Yersinia, Erwinia, Hafnia, Shigella Sonnei, Salmonella arizonae, Serratia, Citrobacter

58
Q

Determines the organism’s ability to oxidatively deaminate phenylalanine to phenylpyruvic acid

A

Phenylalanine Deaminase Test

Morganella, Proteus, and Providencia can be differentiated from other members of the Enterobacteriaceae family

59
Q

Reagent used to determine the presence of phenylpyruvic acid in Phenylalanine Deaminase Test

A

10% Ferric Chloride

60
Q

Positive result of Phenylalanine Deaminase Test

A

Development of Green color upon addition of reagent

61
Q

Positive and Negative QC of Phenylalanine Deaminase Test

A

Postive QC: PPM
Negative QC: E. coli

62
Q

A rapid test used to determine the presence of Tryptophanase

A

Spot Indole Test

RAPID TEST

63
Q

Reagent for Spot Indole Test

A

1% para-dimethylamino-CINNAMALDEHYDE

Indole Test: Para-dimethylamino-BENZALDEHYDE

64
Q

Positive result for Spot Indole Test

A

Development of blue color w/in 20 sec

Negative: No color development/ slight pink

65
Q

Positive QC and Negative QC for Spot Indole Test

A

Positive QC: E. coli
Negative QC: Enterobacter cloacae/K. pneumoniae

Indole Test
Positive QC: E. coli
Negative QC: K. pneumoniae

66
Q

Test used to differentiate Group B Streptococci from other Strep spp.

A

CAMP Test

Christie, Atkins, and Munch-Peterson (CAMP) test

Group B Strep produce CAMP fator > acts synergistically w/ B-lysin of S. aureus = Enhanced Lysis of RBC

67
Q

Media used for CAMP Test

A

BAP

68
Q

Positive Result for CAMP test

A

Enhanced zone of hemolysis (Arrow-head zone of hemolysis)

69
Q

Positive and Negative QC for CAMP Test

A

Positive QC: S. agalactiae
Negative QC: S. pyogenes

All Group B Strep & Listeria monocytogenes = CAMP +

70
Q

Determines the ability of Organisms to hydrolyze the glycoside esculin

A

Esculin Hydrolysis Test

Presumptive identification and differentiation of Enterobacteriaceae

71
Q

Positive result for Esculin Hydrolysis Test

A

Blackening of medium with loss of fluorescence under Wood’s lamp

Negative = No blackening with No loss of fluorescence / Slight blackening w/ no loss of fluorescence

72
Q

Positive & Negative QC of Esculin Hydrolysis Test

A

Positive QC: Klebsiella pneumoniae
Negative QC: Shigella flexneri

73
Q

Determines whether an organism produce gas during glucose fermentation

A

MRS Broth

de Man, Rogosa, and Sharpe broth

Some Lactobacillus spp. and Leuconostoc spp. produce gas

74
Q

Positive result of MRS broth

A

Growth and Gas production indicated by bubble in durham tube

75
Q

Positive & Negative QC for MRS Broth

A

Positive: Leuconostoc (part of the family Lactobacillaceae)
Negative: Pediococcus spp

76
Q

This test is used to differentiate microorganisms based on the ability to oxidize or ferment specific carbohydrates

A

Oxidation/Fermentation (O/F)/ Hugh & Leifson Medium

Oxidation: oxidizing of a compound in the presence of enzymes and molecular oxygen

Fermentation: transformation of sugars to acids and alcohols in the presence of enzymes and absence of molecular oxygen

77
Q

Nonfermentative bacteria are commonly tested for six sugars. What are they?

A

Glucose, Xylose, Mannitol, Lactose, Sucrose, Maltose

78
Q

pH indicator used in Hugh & Leifson medium

A

Bromthymol Blue

*Mnemonic (SHOT tag gsm Blue/ Br) Simmon Citrate, HEA, OF Medium, Thiosulfate Bile Sucrose Agar

79
Q

Positive Result for OF Medium

A

Yellow

Bromthymol Blue: Yellow = Ac, Blue/Green = Alk

In Bailey’s Phenol Red is used: Yellow = Ac, Red = Alk

80
Q

Positive QC for OF Medium

A

Fermenter: E. coli
Oxidizer: P. aeruginosa
Nonutilizer: Alcaligenes faecalis

Alcaligenes = Alkaline = Always Alkaline = CANNOT BREAKDOWN SUGARS

81
Q

Aids in the differentiation E. faecalis & E. faecium

Through their ability to utilize Pyruvate

A

Pyruvate Broth

82
Q

pH indicator used in Pyruvate

A

Bromthymol Blue

NEW MNEMONIC (SHOT ug Br Pre) Simmon Citrate, HEA, OF medium, Thiosulfate Bile Sucrose, Pyruvate

83
Q

Positive result for Pyruvate

A

Yellow

Negative: Blue/Green or no color change
Yellow-green reaction = Weak reaction = Negative

84
Q

Positive and Negative QC for Pyruvate

A

Positive QC: E. faecalis
Negative QC: E. faecium

85
Q

Difference between Minimum Inhibitory Concentration and Minimum Lethal Concentration

A

MIC: Lowest concentration of antimicrobial/drug that will inhibit growth of bacteria after overnight incubation

MLC: Lowest concentration of antimicrobial/drug that will kill a particular bacterium

86
Q

Agar used for Susceptibility Testing

A

Mueller Hinton Agar

87
Q

Depth of Agar for Susceptibility Testing

A

4 mm

88
Q

pH of Agar for Susceptibility Testing

A

7.2 - 7.4

89
Q

Incubation temp and time for Antimicrobial testing

A

37 deg c for 16-18 hours

90
Q

Composition of McFarland standard

A

99.5% H2SO4 & 0.5mL of 1.175% BaCl2

91
Q

This test uses the principle of predefined antibiotic gradient on a plastic strip to generate an MIC value

A

E-test