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BACTERIOLOGY - LAB > Biochemical Test > Flashcards

Biochemical Test Flashcards

1
Q

biochemical reactions bacteria use to break down organic compounds and reactions they use to synthesize new bacterial parts from the resulting carbon skeleton.

A

Bacterial Metabolism

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2
Q

a. Diagnostic schemes analyze each unknown
microorganism for:

A
  1. utilization of various substrates as a carbon
    source
  2. production of specific end products from
    various substrates
  3. production of an acid or alkaline pH in the
    test medium
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3
Q

● Breakdown of chemical substrate through the degradative process of catabolism coupled with oxidation-reduction reactions

A

Energy Production

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4
Q

Bacteria use biochemical pathways to catabolize (breakdown) carbohydrates and produce energy by two mechanisms:

A

Fermentation
Respiration

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5
Q

● anaerobic process carried out by both obligate and facultative anaerobes
● electron acceptor is an organic compound

A

Fermentation

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6
Q

● less efficient in energy generation — beginning substrate is not completely reduced
● a mixture of end products (lactate, butyrate, ethanol, and acetoin) accumulates in the medium — identification of anaerobic bacteria

A

Fermentation

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7
Q

Application of Fermentation

A
  1. Voges-Proskauer
  2. Methyl Red Tests
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8
Q

● efficient energy-generating process
● molecular oxygen is the final electron acceptor
● obligate aerobes and facultative anaerobes

A

Respiration

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9
Q

NOTE!!!!!!!!!!!!!!!!!
● Certain anaerobes can carry out anaerobic respiration, in which inorganic forms of oxygen, such as ____ and ____, act as the final electron acceptors

A

nitrate and sulfate

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10
Q

● ability to use acetamide as the sole source of carbon
● produce acylamidase, which deaminates acetamide to release ammonia resulting in an alkaline pH

A

Acetamide Utilization

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11
Q

Result of Acetamide Ulitization

A

✓Positive: BLUE COLOR
✓Negative: No color change

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12
Q

QC for Acetamide Utilization

A

✓Positive: Pseudomonas aeruginosa
✓Negative: Escherichia coli

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13
Q

● ability to use acetate (sodium acetate) as the sole
● source of carbon differentiate Shigella sp. from Escherichia coli

A

Acetate Utilization

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14
Q

Result for ACETATE UTILIZATION

A

✓Positive: Medium becomes alkalinized = BLUE
✓Negative: No growth or no indicator change to blue

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15
Q

QC for Acetate Utilization

A

✓Positive: Escherichia coli
✓Negative: Shigella sonnei

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16
Q

● presumptive identification and differentiation of Streptococcus pyogenes
● distinguish staphylococci species (resistant) from micrococci (susceptible)

A

Bacitracin (TAXOA) Susceptibility

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17
Q

Result for Bacitracin (TAXOA) Susceptibility

A

✓Positive: ZOI>10 mm
✓Negative: No zone of inhibition

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18
Q

QC for Bacitracin (TAXOA) Susceptibility

A

✓Positive: Streptococcus pyogenes
Micrococcus luteus
✓Negative: Streptococcus agalactiae
Staphylococcus aureus

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19
Q

● differentiates ENTEROCOCCI and GROUP D
STREPTOCOCCI from non–group D viridans
streptococci
● growth in the presence of 4% bile and to hydrolyze esculin to esculetin which reacts with Fe3+ to form dark brown to black precipitate

A

Bile Esculin Test

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20
Q

Result for Bile Esculin Test

A

✓ Positive: GROWTH and BLACKENING of the
agar slant
✓ Negative: Growth and no blackening of medium

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21
Q

QC for Bile Esculin Test

A

✓ Positive: Enterococcus faecalis
✓ Negative: Escherichia coli

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22
Q

● differentiates Streptococcus pneumonia
(positive–soluble) from alpha-hemolytic
streptococci (negative–insoluble)
● Bile/Bile salt (sodium desoxycholate) rapidly lyses pneumococcal colonies
● Lysis depends on amidase → autolytic enzyme

A

Bile Solubility Test

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23
Q

Result for Bile Solubility Test

A

✓ Positive: Colony disintegrate
✓ Negative: Intact colonies

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23
Q

QC for Bile Solubility Test

A

✓ Positive: Streptococcus pneumonia
✓ Negative: Enterococcus faecalis

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24
Q

● detect BUTYRATE ESTERASE
● identification of Moraxella (Branhamella) catarrhalis
● bromochlorindolyl butyrate → indoxyl + O2 → Indigo

A

Butyrate Disk

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25
Q

Result for Butyrate Disk

A

✓ Positive: Development of a BLUE COLOR
(5-minute incubation)
✓ Negative: No color change

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26
Q

QC for Butyrate Disk

A

✓ Positive: Moraxella catarrhalis
✓ Negative: Neisseria gonorrhoeae

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27
Q

● differentiate Streptococcus agalactiae (positive)
from other streptococcal species
● CAMP factor acts synergistically with the beta-lysin of S. aureus to cause enhanced lysis of RBC

A

CHRISTIE, ATKINS, AND MUNCH-PETERSON
(CAMP) TEST

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28
Q

Result for CAMP Test

A

✓Positive: Arrowhead-shaped zone of
beta-hemolysis
✓Negative: No enhancement of hemolysis

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29
Q

QC for CAMP Test

A

✓Positive: Streptococcus agalactiae
✓Negative: Streptococcus pyogenes

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30
Q

CAMP Positive Organisms

A
  1. Streptococcus agalactiae
  2. Listeria monocytogenes
  3. Proprionibacterium acnes
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31
Q

Revere CAMP Positive Organisms

A
  1. Clostridium perfringens
  2. Corynebacterium pseudotuberculosis
  3. Corynebacterium ulcerans
  4. Corynebacterium urealyticum
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32
Q

● differentiates catalase-positive MICROCOCCAL and STAPHYLOCOCCAL spp. from catalase-negative
STREPTOCOCCAL spp.
● H2O2 → H2O + O = EFFERVESCENCE

A

CATALASE TEST

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33
Q

Result for CATALASE TEST

A

✓ Positive: Copious bubbles are produced
✓ Negative: No or few bubbles are produced

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34
Q

QC for CATALASE TESTCATALASE TEST

A

✓ Positive: Staphylococcus aureus
✓ Negative: Streptococcus pyogenes

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35
Q

● isolate and purify Pseudomonas aeruginosa from contaminated specimens
● ability of an organism to grow in the presence of cetrimide

A

Cetrimide Agar

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36
Q

Result for Cetrimide Agar

A

✓ Positive: Growth, variation in color of colonies
✓ Negative: No growth

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37
Q

QC for Cetrimide Agar

A

✓ Positive: Pseudomonas aeruginosa
✓ Negative: Escherichia coli

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38
Q

● ability to use SODIUM CITRATE (sole carbon source) and inorganic ammonium salts (sole nitrogen source)
● citrate-permease converts citrate to pyruvate
● ammonium phosphate → ammonia and ammonium hydroxide→ alkaline pH → BROMTHYMOL BLUE indicator from green to blue

A

Citrate Utilization

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39
Q

Result for Citrate Utilization

A

✓ Positive: Growth on the medium = BLUE
✓ Negative: Absence of growth

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40
Q

QC for Citrate Utilization

A

✓ Positive: Enterobacter aerogenes
✓ Negative: Escherichia coli

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41
Q

● differentiate S. aureus (+) from coagulase-negative staphylococci

A

Coagulase Test

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42
Q

Two forms of Coagulase

A
  1. Bound Coagulase→ clumping factor
  2. Free Coagulase→ extracellular protein enzyme
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43
Q

Result for Coagulase-Slide Test

A

✓ Positive: Clumping in 10 seconds or less
✓ Negative: No clumping

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44
Q

Result for Coagulase-Tube Test

A

✓ Positive: Clot of any size
✓ Negative: No clot

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45
Q

QC for Coagulase-Test

A

✓ Positive: Staphylococcus aureus
✓ Negative: Staphylococcus epidermidis

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46
Q

● differentiate decarboxylase producing
Enterobacteriaceae from other gram-negative
rods
● Amino acid → Amine = alkaline pH →from orange to purple
● pH indicator: BROMCRESOL PURPLE

A

Decarboxylase Tests (Moeller’s Method)

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47
Q

Result for Decarboxylase Tests (Moeller’s Method)

A

✓ Positive: Alkaline (PURPLE) color change
✓ Negative: No color change or acid (yellow)

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48
Q

QC for Decarboxylase Tests (Moeller’s Method)

A

✓ Positive:
▪ Lysine—Klebsiella pneumoniae
▪ Ornithine—Enterobacter aerogenes
▪ Arginine—Enterobacter cloacae
✓ Negative:
▪ Lysine—Enterobacter cloacae
▪ Ornithine—Klebsiella pneumoniae
▪ Arginine—Klebsiella pneumoniae

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49
Q

● distinguish Serratia sp. (+) from Enterobacter sp., Staphylococcus aureus (+) from other species, and Moraxella catarrhalis (+) from Neisseria sp.
● ability to hydrolyze DNA (DNAase)
● DNA–methyl green complex→ from green to colorless zone

A

DNA Hydrolysis (DNAse Test Agar)

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50
Q

Result for DNA Hydrolysis (DNAse Test Agar)

A

✓ Positive: COLORLESS around the test organism
✓ Negative: Medium remains green

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51
Q

QC for DNA Hydrolysis (DNAse Test Agar)

A

✓ Positive: Staphylococcus aureus
✓ Negative: Escherichia coli

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52
Q

● presumptive identification and differentiation of Enterobacteriaceae
● Esculin is hydrolyzed to esculetin, which reacts with Fe3+ and forms a dark brown to black precipitate

A

Esculin Hydrolysis

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53
Q

Result for Esculin Hydrolysis

A

✓ Positive: BLACKENED MEDIUM
✓ Negative: No blackening

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54
Q

QC for Esculin Hydrolysis

A

✓ Positive: Enterococcus faecalis
✓ Negative: Escherichia coli

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55
Q

● ability to ferment carbohydrates

A

Fermentation Media

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56
Q

differentiate enteric bacteria from
coryneforms

A

ANDRADE’S FORMULA

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57
Q

Result for ANDRADE’S FORMULA

A

✓ Positive: Indicator change to PINK
✓ Negative: Growth, but no change in color

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58
Q

QC for ANDRADE’S FORMULA

A

✓ Positive, with gas: Escherichia coli
✓ Positive, no gas: Shigella flexneri

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59
Q

distinguish enterococci from streptococci

A

Bromocresol Purple

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60
Q

Result for Bromocresol Purple

A

✓ Positive: Indicator change to YELLOW
✓ Negative: Growth, but no change in color

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61
Q

QC for Bromocresol Purple

A

✓ Positive, with gas: Escherichia coli
✓ Negative, no gas: Moraxella osloensis

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62
Q

● presence and arrangement of flagella

A

Flagellar Stain (Wet Mount Technique)

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63
Q

QC for Flagellar Stain (Wet Mount Technique)

A

✓ Peritrichous: Escherichia coli
✓ Polar: Pseudomonas aeruginosa
✓ Negative: Klebsiella pneumonia

64
Q

MOTILITY of diff. Bacteria in Flagellar Stain

A

● Rapid darting/shooting star = Vibrio (monotrichous)
● Darting = Campylobacter
● Twitching = Kingella, Bartonella
● Tumbling (end over end) = Listeria
● Gliding = Capnocytophaga, Mycoplasma
pneumoniae
● Corkscrew (axial filaments) = Spirochetes
● Spinning = Leptospira

65
Q

➢ gelatinases hydrolyze gelatin
➢ presumptive identification of Staphylococcus sp., Enterobacteriaceae, and some gram-positive bacilli

A

Gelatin Hydrolysis

66
Q

Result for Gelatin Hydrolysis

A

✓ Positive: Partial or total liquefaction at 4°C within 14 days
✓ Negative: Complete solidification

67
Q

QC for Gelatin Hydrolysis

A

✓ Positive: Bacillus subtilis
✓ Negative: Escherichia coli

68
Q

● differentiate a pyocyanogenic pseudomonads from other Pseudomonas spp.
● ability of an organism to grow at 42°C

A

GROWTH @ 42°C TEST

69
Q

Result for Growth @ 42°C Test

A

✓ Positive: Good growth at both 35°and 42°C
✓ Negative: No growth at 42°C but good growth at 35°C

70
Q

QC for Growth @ 42°C Test

A

✓ Positive: Pseudomonas aeruginosa
✓ Negative: Pseudomonas fluorescens

71
Q

● HIPPURICASE hydrolyzes hippuric acid→ GLYCINE AND BENZOIC ACID
● Glycine is deaminated by ninhydrin, which is reduced during the process
● end products of the ninhydrin oxidation react to form a PURPLE- COLORED PRODUCT

A

Hippurate Hydrolysis

72
Q

Result for Hippurate Hydrolysis

A

✓ Positive: Deep purple color
✓ Negative: Colorless or slightly yellow pink color

73
Q

QC for Hippurate Hydrolysis

A

✓ Positive: Streptococcus agalactiae
✓ Negative: Streptococcus pyogenes

74
Q

Bacteria in Hippurate Hydrolysis

A
  1. Streptococcus agalactiae
  2. Listeria monocytogenes
  3. Campylobacter jejuni subsp. jejuni
  4. Gardnerella vaginalis
75
Q

Tryptophan → INDOLE + KOVAC’S REAGENT
(dimethylamine-benzaldehyde and hydrochloride) or EHRLICH’S REAGENT = RED COLOR

A

Indole Production

76
Q

Result for Indole Production

A

✓ Positive: PINK- TO WINE-COLORED RING
✓ Negative: No color change

77
Q

QC for Kovac’s Method (Indole)

A

✓ Positive: Escherichia coli
✓ Negative: Klebsiella pneumoniae

78
Q

QC for Ehrlich’s Method (Indole)

A

✓ Positive: Haemophilus influenzae
✓ Negative: Haemophilus parainfluenzae

79
Q

QC for Kovac’s Method - Anaerobic (Indole)

A

✓ Positive: Porphyromonas asaccharolytica
✓ Negative: Bacteroides fragilis

80
Q

presumptive identification of CATALASE-NEGATIVE GRAM- POSITIVE COCCI
● Hydrolysis of Leucine beta-naphthylamide by
leucine aminopeptidase → beta-naphthylamine + cinnamaldehyde reagent = RED COLOR

A

Leucine Aminopeptidase (LAP) Test

81
Q

Result for Leucine Aminopeptidase (LAP) Test

A

✓ Positive: Development of a red color within 1
minute
✓ Negative: No color change or development of a slight yellow color

82
Q

QC for Leucine Aminopeptidase (LAP) Test

A

✓ Positive: Enterococcus faecalis
✓ Negative: Aerococcus viridans

83
Q

● ability to metabolize litmus milk: fermentation, reduction, clot formation, digestion, and the formation
of gas

A

Litmus Milk Medium

84
Q

Result for Litmus Milk Medium

A

➢ Fermentation of lactose → litmus turns pink
➢ Sufficient acid: casein is coagulated→ solidifying the milk
➢ hydrolyze casein→ straw colored
➢ reduce litmus→ colorless in the bottom of the tube

84
Q

QC for Litmus Milk Medium

A

➢ Fermentation: Clostridium perfringens
➢ Acid: Lactobacillus acidophilus
➢ Peptonization: Pseudomonas aeruginosa

85
Q

● LIA: lysine, peptones, a small amount of glucose, ferric ammonium citrate, and sodium thiosulfate
● GLUCOSE FERMENTED→ BUTT BECOMES
ACIDIC (YELLOW)
● LYSINE DECARBOXYLASE PRESENT
→CADAVERINE → ALKALINE STATE (PURPLE)
● OXIDATIVE DEAMINATION of lysine and in the presence of FERRIC AMMONIUM CITRATE and FLAVIN MONONUCLEOTIDE, forms BURGUNDY COLOR on the slant

A

Lysine Iron Agar

86
Q

● pH indicator: Bromocresol Purple
▪ yellow at or below pH 5.2
▪ purple at or above pH 6.8

A

Lysine Iron Agar

87
Q

Result for Lysine Iron Agar

A

✓Alkaline slant/alkaline butt (K/K)—lysine
decarboxylation and no fermentation of glucose
✓Alkaline slant/acid butt (K/A)—glucose fermentation
✓Red slant/acid butt (R/A)—lysine deamination and glucose

88
Q

QC for Lysine Iron Agar

A

✓Alkaline slant and butt: H2S positive: Citrobacter freundii
✓Alkaline slant and butt: Escherichia coli
✓Alkaline slant and butt: H2S positive: Salmonella
typhimurium
✓Red slant, acid butt: Proteus mirabilis

89
Q

LIA reaction for Salmonella

A

K/K

90
Q

LIA reaction for Shigella and Citrobacter

A

K/A

91
Q

LIA reaction for Proteus, Providencia, Morganella (PPM)

A

R/A

92
Q

● ability to produce and maintain stable acid end products from glucose fermentation, overcome the buffering capacity of the system, and to determine the ability to produce 2,3-BUTANEDIOL or ACETOIN from glucose fermentation

A

Methyl Red/Voges-Proskauer (MR-VP) Tests

93
Q

o detects mixed acid fermentation that lowers the pH
o red at pH 4.4 and yellow at pH 6.2

A

Methyl Red

94
Q

o detects the ability to convert the acid products to acetoin and 2,3- butanediol → alpha-naphthol is added, followed by potassium hydroxide (KOH) → RED

A

Voges-Proskauer Test

95
Q

QC for MR-VP Tests

A

✓ MR positive/VP negative: Escherichia coli
✓ MR negative:/VP positive: Enterobacter aerogenes

96
Q

Medium for MR-VP Tests

A

MR-VP medium or Clurk and Lubs Dextrose
Broth

97
Q

● differentiate STAPHYLOCOCCUS from MICROCOCCUS SPP. by detection of the enzyme oxidase
● oxidase reacts with the oxidase reagent and cytochrome C to form the indophenol

A

Microdase Test (Modified Oxidase)

98
Q

Result for Microdase Test (Modified Oxidase)

A

✓ Positive: Development of BLUE TO
PURPLE-BLUE COLOR
✓ Negative: No color change

99
Q

QC for Microdase Test (Modified Oxidase)

A

✓ Positive: Micrococcus luteus
✓ Negative: Staphylococcus aureus

100
Q

● diffuse zone of growth extending out from the line of inoculation

A

Motility Testing

101
Q

Result for Motility Testing

A

✓ Positive: Spread out from the site of inoculation
✓ Negative: Remain at the site of inoculation

102
Q

QC for Motility Testing

A

✓ Positive: Escherichia coli
✓ Negative: Staphylococcus aureus

103
Q

● determine gas formation during glucose fermentation
● Lactobacillus spp. and Leuconostoc sp. produce gas
● Selective medium: SODIUM ACETATE and AMMONIUM CITRATE

A

MRS Broth

104
Q

Result for MRS Broth

A

✓ Positive: Leuconostoc sp. - Growth, gas
production indicated by a bubble in the Durham tube
✓ Positive: Lactobacillus spp. - Growth, no gas
production
✓ Negative: No growth

105
Q

QC for MRS Broth

A

✓ Positive: Lactobacillus lactis
✓ Negative: Escherichia coli

106
Q

● presumptively identify various genera of
Enterobacteriaceae and verotoxin-producing E. coli (neg)
● B-d-glucuronidase hydrolyzes
4-methylumbelliferyl-ẞ-d-glucuronide to
4-methylumbelliferyl which fluoresces blue under long wavelength UV

A

4-METHYLUMBELLIFERYL-SS-D-GLUCURONIDE
(MUG) TEST

107
Q

Result for MUG test

A

✓ Positive: Electric blue fluorescence
✓ Negative: Lack of fluorescence

108
Q

QC for MUG Test

A

✓ Positive: Escherichia coli
✓ Negative: Klebsiella pneumoniae

109
Q

● nitrate reductase converts the nitrate (NO3) to nitrite (NO2)
● reduction is determined by adding SULFANILIC ACID and ALPHA- NAPHTHYLAMINE
● sulfanilic acid and nitrite react to form a diazonium salt→ couples with the alpha naphthylamine to produce a red,
water-soluble azo dye
● Zinc is added to validate colorless result for the presence of untreated nitrate

A

Nitrate Reduction

110
Q

Result for Nitrate Reduction

A

✓ Positive: RED
✓ Negative: No color change

111
Q

QC for Nitrate Reduction

A

✓ Positive: NO3+, no gas: Escherichia coli
✓ Positive: NO3+, gas: Pseudomonas aeruginosa
✓ Negative: Acinetobacter baumannii

112
Q

● reducing nitrite to nitrogen do not turn color and do produce gas in the nitrate reduction test

A

Nitrite Reduction

113
Q

Result for Nitrite Reduction

A

✓ Positive: No color change to red 2 minutes; gas production in Durham tube
✓ Negative: Broth becomes red; no gas production is observed

114
Q

QC for Nitrite Reduction

A

✓ Positive: Proteus mirabilis
✓Negative: Acinetobacter baumannii

115
Q

● ability to produce B-GALACTOSIDASE which hydrolyzes substrate ONPG to form orthonitrophenol (yellow product)
● distinguishes late LLF from NLF of Enterobacteriaceae
● Indicates presence of B-galactosidase

A

O-NITROPHENYL-B-D-GALACTOPYRANOSIDE
(ONPG) TEST

116
Q

Result for ONPG Test

A

✓ Positive: YELLOW (presence of B-galactosidase)
✓ Negative: Colorless

117
Q

QC for ONPG Test

A

✓ Positive: Shigella sonnei
✓ Negative: Salmonella typhimurium

118
Q

● aka ETHYL HYDROCUPREINE HYDROCHLORIDE
● lyses Streptococcus pneumoniae (positive test), but alpha-streptococci are resistant (negative test)
● zone of 14 to 16 mm is considered susceptible
● presumptive identification of Streptococcus pneumoniae

A

OPTOCHIN (TAXO P) SUSCEPTIBILITY TEST

119
Q

Result for OPTOCHIN (TAXO P) SUSCEPTIBILITY TEST

A

✓ Positive: ZOI ≥ 14 mm in diameter, with 6-mm disk
✓ Negative: No zone of inhibition

120
Q

QC for OPTOCHIN (TAXO P) SUSCEPTIBILITY TEST

A

✓ Positive: Streptococcus pneumoniae
✓ Negative: Streptococcus pyogenes

121
Q

presence of cytochrome oxidase which oxidize
TETRAMETHYL-p- PHENYLENEDIAMINE
DIHYDROCHLORIDE to indophenol (DARK PURPLE)
● identification of oxidase-negative Enterobacteriaceae, differentiating them from other Gram (-) bacilli

A

OXIDASE TEST (KOVAC’S METHOD)

122
Q

Result for OXIDASE TEST (KOVAC’S METHOD)

A

✓ Positive: Development of a dark purple color within 10
✓ Negative: Absence of color

123
Q

QC for OXIDASE TEST (KOVAC’S METHOD)

A

✓ Positive: Pseudomonas aeruginosa
✓Negative: Escherichia coli

124
Q

Reagent for the Oxidase Test for Neisseria

A

Reagent: 1% dimethyl-p-phenylenediamine hydrochloride
(+): colonies become purple black

125
Q

Reagent for the Indophenol Method

A

Reagent: p-aminodimethylaniline hydrochloride (or Oxalate) and alpha-naphthol
(+): Intense Blue color within 2 minutes

126
Q

● ability to oxidize or ferment specific carbohydrates
● glucose, xylose, mannitol, lactose, sucrose, and maltose

A

OXIDATION/FERMENTATION (OF) MEDIUM (CDC METHOD)

127
Q

● low peptone-to-carbohydrate ratio and a limiting amount of carbohydrate
● reduced peptone limits the formation of alkaline amines that may mask acid production resulting from oxidative metabolism

A

Hugh and Leifson’s Formula

128
Q

Carbohydrate Fermentation Medium that is Base Medium

A

a. Peptone water
b. Trypticase
c. Tryptone B

129
Q

Carbohydrate Fermentation Medium that is pH indicators

A

a. Bromcresol Purple → Purple (alk) to Yellow(acid) at pH 6.3
b. Andrade’s Acid Fuchsin → Pale Yellow (alk) to Reddish Pink (acid) at pH 5.5
c. Phenol Red → Red (alk) to Yellow at pH 7.9

130
Q

Other Methods for Fermentation

A
  1. Rusell’s Double Sugar (RDS)
    ● contains glucose and lactose with Andrade’ Acid Fuchsin
  2. Smith Fermentation Tube
131
Q

Result for OF Medium

A

✓ Positive: Acid production (A) indicated by the color indicator changing to yellow
✔Weak-positive (Aw): Weak acid formation
✔Negative: Red or alkaline (K) color in the deep No change (NC) or neutral (N)

132
Q

QC for OF Medium

A

✔ Fermenter (Glucose): Escherichia coli
✓ Oxidizer (Glucose): Pseudomonas aeruginosa

133
Q

● ability to oxidatively deaminate phenylalanine to phenylpyruvic acid
● Morganella, Proteus, and Providencia can be
differentiated from other members of the
Enterobacteriaceae family
● Phenylpyruvic acid → detected by adding a few drops of 10% FERRIC CHLORIDE→ green colored complex

A

Phenylalanine Deaminase Agar

134
Q

Result for Phenylalanine Deaminase Agar

A

✓ Positive: GREEN COLOR on slant
✓ Negative: Slant remains original color

135
Q

QC for Phenylalanine Deaminase Agar

A

✓ Positive: Proteus mirabilis
✓ Negative: Escherichia coli

136
Q

● presumptive identification of Streptococcus pyogenes and enterococci by the presence of L-pyrrolidonyl arylamidase
● L-pyrrolidonyl- B-naphthylamide → B-naphthylamine + N,N- methylaminocinnamaldehyde reagent → BRIGHT RED PRECIPITATE

A

L-PYRROLIDONYL ARYLAMIDASE (PYR) TEST

137
Q

Result for L-PYRROLIDONYL ARYLAMIDASE (PYR) TEST

A

✓ Positive: Bright red color within 5 minutes
✓ Negative: No color change or an orange color

138
Q

QC for L-PYRROLIDONYL ARYLAMIDASE (PYR) TEST

A

✓ Positive: Enterococcus faecalis
Streptococcus pyogenes
✓ Negative: Streptococcus agalactiae

139
Q

● ability of an organism to utilize pyruvate
● differentiation between Enterococcus faecalis (+) Enterococcus faecium (-)
● Pyruvic acid → added to the broth to determine whether the microorganism is able to use pyruvate
● Bromothymol blue indicator changes from blue to yellow

A

Pyruvate Broth

140
Q

Result for Pyruvate Broth

A

✓ Positive: Indicator changes from green to yellow
✓ Negative: No color change

141
Q

QC for Pyruvate Broth

A

✓ Positive: Enterococcus faecalis
✓ Negative: Streptococcus bovis

142
Q

● ability of an organism to grow in high concentrations of salt
● differentiate enterococci (+) from nonenterococci (-)
● Medium: Brain-Heart Infusion Broth containing 6.5% NaCl
● Indicator: Bromocresol Purple

A

Salt Tolerance Test

143
Q

Result for Salt Tolerance Test

A

✓ Positive: Visible turbidity in the broth, with or
without a color change from purple to yellow
✔ Negative: No turbidity and no color change

144
Q

QC for Salt Tolerance Test

A

✓ Positive: Enterococcus faecalis
✓ Negative: Streptococcus bovis

145
Q

● determines whether Gram (-) rod ferments glucose and lactose or sucrose and forms hydrogen sulfide (H2S)
● differentiate members of the Enterobacteriaceae family from other gram (-) rods

A

Triple Sugar Iron Agar (TSI)

146
Q

● Composition: 10 parts Lactose, 10 parts sucrose, 1 part glucose and peptone
● Phenol Red → pH indicator
● Ferrous Ammonium Sulfate → H2S Indicator
● CO2 and hydrogen gas (H2) → presence of bubbles or cracks or by separation of the agar

A

Triple Sugar Iron Agar (TSI)

147
Q

Result for TSI

A

✓ Alkaline slant/ Alkaline butt (K/K) → glucose,
lactose, and sucrose nonutilizer
✓ Alkaline slant/Acid butt (K/A) → glucose
fermentation only
✓ Acid slant/Acid butt (A/A) → glucose, sucrose,
and/or lactose fermenter
✓ Black Precipitate → production of ferrous sulfide and H2S gas (H2S+)
✓ Bubbles or cracks → gas production

148
Q

QC for TSI

A

✓ A gas production: Escherichia coli
✓ K/A, +/- gas production, H2S+: Salmonella
typhimurium
✓ K/K: Pseudomonas aeruginosa
✓ K/A, H2S+: Proteus mirabilis
✓ K/A: Shigella flexner

149
Q

● ability to produce urease, which hydrolyzes urea to ammonia and CO2
● Proteus sp. → rapidly hydrolyze urea
● ammonia alkalinizes the medium
● pH Indicator: PHENOL RED → from light orange at pH 6.8 to magenta (pink) at pH 8.1
● Medium: CHRISTENSEN’S UREA AGAR or BROTH

A

Urease Test (Christensen’s Method)

150
Q

Result for Urease Test (Christensen’s Method)

A

✓ Positive: Change in color of slant from light orange to magenta
✓ Negative: No color change

151
Q

QC for Urease Test (Christensen’s Method)

A

✓ Positive: Proteus vulgaris
✓ Weak positive: Klebsiella pneumonia
✓ Negative: Escherichia coli

152
Q

● differentiation Haemophilus species

A

X and V Factor Test

153
Q

Result for X and V Factor Test

A

✓ Positive:
* Growth around the XV disk → requirement
for both factors
▪ Growth around the V disk, no growth
around the X disk, and light growth around
the XV disk shows a V factor requirement
✓ Negative: Growth over the entire surface of the agar indicates no requirement for either X or V factor

154
Q

QC for X and V Factor Test

A

✓ Haemophilus influenza → halo of growth around the XV disk, no growth on the rest of the agar surface
✓ Haemophilus parainfluenzae → halo of growth around the XV and V disks
✓ Haemophilus ducreyi → halo of growth around the XV and X disks

155
Q

heat stable substance known as HEMIN or HEMATIN

A

X factor

156
Q

heat labile substance known as NAD or COENZYME I

supplied by yeast, potato extract and bacteria
(Staphylococci, Pneumococci and Neisseria)

A

V factor

BACTERIOLOGY - LAB (6 decks)

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