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Bacteriology > Biochemical Identification of Gram Negative Bacteria (LEC/LAB) > Flashcards

Biochemical Identification of Gram Negative Bacteria (LEC/LAB) Flashcards

1
Q

Gram stain reaction and morphology of Enterobacteriaceae

A

Gram Negative (-) Bacilli and Cocobacilli

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2
Q

Aerotolerance of Enterobacteriaceae

A

Facultative Anaerobes

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3
Q

Enterobacteriaceae do not produce ________.

A

Cytochrome C oxidase

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4
Q

Which member of Enterobacteriaceae produces cytochrome c oxidase?

A

Plesiomonas spp.

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5
Q

TRUE OR FALSE.
Enterobacteriaceae family produces cytochrome C oxidase.

A

False

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6
Q

Which carbohydrate/s can be fermented by the members of Enterobacteriaceae?

A

Glucose

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7
Q

Are Enterobacteriaceae motile?

A

Yes (at room temperature)

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8
Q

At which temperature are Enterobacteriaceae motile?

A

Room Temperature (20-25 C)

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9
Q

Which member/s of the Enterobacteriaceae family are not motile at room temperature?

A

MNEMONIC: SKY
* Shigella spp.
* Klebsiella spp.
* Yersinia spp.

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10
Q

Specimen of Choice for Enterobacteriaceae

A

Fecal/Stool Specimens

Collected within first 4 days of illness & before administration of ATBs

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11
Q

Specimen Collection

Fecal/stool specimens are collected within ____ of illness and before administration of antibiotics.

A

first 4 days

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12
Q

Specimen Collection

Specimens should be processed within ____ of collection.

A

1-2 hours

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13
Q

Specimen Collection

What should be done if the specimen cannot be processed within the ideal time frame (1-2 hours)?

A

Placed in a transport medium at the temperature of 4 C

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14
Q

Specimen Collection

Specimens in a transport medium must be kept at a temperature of ____.

A

4 C

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15
Q

Specimen Collection

Transport medium for Enterobacteriaceae

A
  • Cary-Blair
  • Amies
  • Stuart
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16
Q

Which step in biochemical identification of Enterobacteriaceae is not helpful in identifying enteric pathogens?

A

Direct Smear Examination/Direct Microscopic Examination/Gram Staining

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17
Q

Which specimen sample is not helpful in direct smear preparation for identifying enteric pathogens?

A

Stool

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18
Q

Direct smear preparation of stool samples may reveal the presence of ______.

A

inflammatory cells

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19
Q

Enterobacteriaceae grow at an optimal temperature of ______.

A

35 - 37 C

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20
Q

Which organism/s is/are being described?

Grow at low temperatures (1-5 C)

A
  • Serratia spp.
  • Yersinia spp.
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21
Q

Serratia spp. and Yersinia spp. grow at a temperature of ______.

A

1 - 5 C

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22
Q

Which organism/s is/are being described?

Grow at high temperatures (45-50 C)

A

Escherichia coli

TIP: Read it as Escherichia colHIGH

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23
Q

Escherichia coli grows at a temperature of _____.

A

45 - 50 C

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24
Q

Colonies of Enterobacteriaceae are visible after ____ of incubation.

A

18 - 24 hours

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25
Q

Common culture media used or Enterobacteriaceae

A
  • BAP
  • CAP
  • MacConkey Agar

EMB, HEA

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26
Q

Colonial appearance of Enterobacteriaceae on BAP and CAP

A

Large, gray, and smooth

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27
Q

Which organism/s is/are being described?

Most likely to have mucoid colonies

A
  • Klebsiella spp.
  • Enterobacter spp.
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28
Q

Klebsiella spp. and Enterobacter spp. are most likely to have ____ colonies.

A

mucoid

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29
Q

A factor that contributes to the mucoid appearance of Klebsiella spp. and Enterobacter spp. is the _____.

A

Polysaccharide Capsule

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30
Q

Which organism/s is/are being described?

Most likely to produce a “swarm” on blood and chocolate agars

A

ACRONYM: MVP
* Proteus mirabilis
* Proteus vulgaris
* Proteus penneri

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31
Q

Proteus mirabilis, Proteus vulgaris, and Proteus penneri are most likely to produce a ____ on blood and chocolate agars.

A

swarm

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32
Q

Which organism/s is/are being described?

Pinpoint colonies at 5% SBA after 24 hours of incubation

A

Yersinia pestis

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33
Q

Y. pestis colonial appearance on 5% SBA after 24 hours of incubation

A

Pinpoint

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34
Q

Which culture medium is utilized to produce pinpoint Y. pestis colonies?

A

5% SBA

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35
Q

Pinpoint colonies of Y. pestis on 5% SBA is produced after ____ of incubation.

A

24 hours

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36
Q

Which organism/s is/are being described?

Rough, cauliflower appearance of colonies at 5% SBA after 48 hours of incubation

A

Yersinia pestis

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37
Q

Y. pestis colonial appearance on 5% SBA after 48 hours of incubation

A

Rough, cauliflower

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38
Q

Which culture medium is utilized to produce rough, cauliflower appearance of Y. pestis colonies?

A

5% SBA

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39
Q

Rough, cauliflower appearing colonies of Y. pestis on 5% SBA is produced after ____ of incubation.

A

48 hours

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40
Q

Characteristic of Yersinia pestis grown in broth cultures

A

Stalactite Pattern

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41
Q

Which organism/s is/are being described?

Exhibits a “stalactite pattern” when grown in broth cultures

A

Yersinia pestis

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42
Q

Which organism/s is/are being described?

It produces “bull’s-eye” colonies

A

Yersinia enterocolitica

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43
Q

Yersinia entercolitica produces ____ colonies

A

bull’s-eye

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44
Q

Mucoid colonies form a ____ when a loop tries to pick it up.

A

string

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45
Q

Rapid Lactose Fermenters

A

MNEMONIC: EKE
* Escherichia coli
* Klebsiella spp.
* Enterobacter spp.

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46
Q

Rapid Lactose Fermenters ferment lactose within _____.

A

18 - 24 hours

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47
Q

________ ferment lactose within 18-24 hours.

A

Rapid Lactose Fermenters

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48
Q

Late Lactose Fermenters

A
  • Hafnia spp.
  • Serratia spp.
  • Citrobacter spp.
  • Salmonella arizonae
  • Shigella sonnei
  • Yersinia enterocolitica
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49
Q

Late Lactose Fermenters ferment lactose within _____.

A

48 - 72 hours

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50
Q

________ ferment lactose within 48-72 hours.

A

Late Lactose Fermenters

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51
Q

Non-Lactose Fermenters

A
  • All Salmonella EXCEPT S. arizonae
  • All Shigella EXCEPT S. sonnei
  • All Yersinia EXCEPT Y. enterocolitica
  • Proteus spp.
  • Providencia spp.
  • Morganella spp.
  • Edwardsiella spp.
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52
Q

Which medium is best used for characterizing gram (-) bacilli?

A

MacConkey Agar

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53
Q

What kind of medium (according to function) is MAC agar?

A

Selective and Differential

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54
Q

How is MAC agar selective?

A

Selective for gram negative (-) enteric bacilli

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55
Q

How is MAC agar differential?

A

Differentiates lactose from non-lactose fermenters

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56
Q

Lactose fermenters will color the MAC agar _____.

A

Dark Pink

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57
Q

Non-Lactose fermenters will color the MAC agar _____.

A

Colorless

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58
Q

The red pigment of Serratia marcescens on MAC agar is due to the _______.

A

Production of Prodigiosin

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59
Q

Which species produces a greenish-metallic sheen on EMB agar?

A

Escherichia coli

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60
Q

Which Biochemical Test?

To determine glucose and lactose, or sucrose utilization and hydrogen sulfide production.

A
  • Triple Sugar Iron Agar (TSI)
  • Kligler Iron Agar (KIA)
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61
Q

Purpose of TIA and KIA Test

A

To determine glucose and lactose, or sucrose utilization and hydrogen sulfide production.

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62
Q

Which Biochemical Test?

To determine the end-products of glucose fermentation.

A
  • Methyl Red
  • Voges-Proskauer
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63
Q

Purpose of Methyl Red and VP Test

A

To determine the end-products of glucose fermentation

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64
Q

Which Biochemical Test?

To determine whether an indole was formed from tryptophan by tryptophanase.

A

Indole Test

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65
Q

Purpose of Indole Test

A

To determine whether indole was formed from tryptophan by tryptophanase

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66
Q

Which Biochemical Test?

To determine the hydrolysis of Urea

A

Urease Test

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67
Q

Purpose of Urease Test

A

To determine hydrolysis of Urea

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68
Q

Which Biochemical Test?

To determine whether citrate can be used as a sole carbon source

A

Simmons’ Citrate

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69
Q

Purpose of Simmons’ Citrate

A

To determine whether citrate can be used as a sole carbon source

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70
Q

Which Biochemical Test?

To determine lysine decarboxylase activity

A

Lysine Iron Agar (LIA)

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71
Q

Purpose of LIA

A

To determine lysine decarboxylase activity

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72
Q

Carbohydrate Utilization Tests

A
  • Oxidation-Fermentation Tests
  • Triple Sugar Iron Agar Test
  • Ortho-Nitrophenyl-B-D-Galactopyranoside Test (ONPG)
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73
Q

Carbohydrate Utilization

Two enzymes necessary for taking up lactose and cleaving it into monosaccharides

A
  • β-galactoside permease (lactose permease)
  • β-galactosidase
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74
Q

A transport enzyme which facilitates the entry of lactose in the plasma membrane of bacteria.

A

β-galactoside permease (lactose permease)

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75
Q

What does β-galactoside permease do?

A

It acts as a transport enzyme, which facilitates the entry of lactose in the plasma membrane of the bacteria.

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76
Q

β-galactoside permease is also known as _____.

A

Lactose Permease

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77
Q

It hydrolyzes lactose into glucose and galactose

A

β-galactosidase

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78
Q

What does β-galactosidase do?

A

It hydrolyzes lactose into glucose and galactose

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79
Q

RLFs contain the enzyme _________.

A

β-galactoside permease and β-galactosidase

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80
Q

NLFs contain the enzyme _________.

A

None

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81
Q

LLFs contain the enzyme ____.

A

β-galactosidase

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82
Q

Which medium is used for Oxidation-Fermentation Test?

A

OF Basal Medium

E.g., Hugh-Leifson OFBM

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83
Q

What is the pH indicator for Oxidation-Fermentation Test?

A

Bromthymol blue

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84
Q

Color of uninoculated OFBM

A

Green

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85
Q

OFBM color of acid environment

A

Yellow

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86
Q

OFBM color of alkaline environment

A

Blue

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87
Q

How is Oxidation-Fermentation Test performed?

A
  1. Two tubes of Hugh-Leifson OFBM are inoculated.
  2. One tube is overlaid with sterile mineral oil to promote an anaerobic environment (closed).
  3. The other tube is without mineral oil to promote an aerobic environment (open).
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88
Q

What is added to the OFBM medium to promote an anaerobic environment?

A

Sterile mineral oil

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89
Q

Sterile mineral oil is used for ______.

A

promoting an anaerobic environment

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90
Q

Reactions in OF Test

When acid is produced on both tubes, it means that _______.

A

The organism is both an oxidizer and fermenter

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91
Q

Reactions in OF Test

When acid is produced only in the closed tube, it means that _______.

A

The organism is a fermenter and possible an obligate anaerobe

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92
Q

Reactions in OF Test

When acid is produced only in the open tube, it means that _______.

A

The organism is an oxidizer

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93
Q

OFBM contains ____.

A

1% Carbohydrate

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94
Q

Composition of Triple Sugar Iron Agar (TIA)

A
  • 10 parts Lactose
  • 10 parts Sucrose
  • 1 part Glucose
  • Peptone
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95
Q

What is the pH indicator for Triple Sugar Iron Agar (TSI)?

A

Phenol red

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96
Q

What is the H2S indicator for Triple Sugar Iron Agar (TSI)?

A

Ferrous sulfate and Sodium thiosulfate

97
Q

If the pH indicator of TSI turns yellow, it means that ______.

A

it is acidic

98
Q

When the pH of TSI drops to 6.8, it means that ______.

A

it is acidic

99
Q

What is the color of TSI when carbohydrate is utilized?

A

Yellow

100
Q

What is the color of TSI when carbohydrate is not utilized?

A

Red

101
Q

What is the color of TSI when there is a production of H2S?

A

Black

102
Q

The butt portion of the TSI determines if the organism is able to ferment _____.

A

Glucose

103
Q

Which portion of the TSI determines if the organism is a glucose fermenter?

A

Butt

104
Q

Which portion of the TSI is anaerobic?

A

Butt

105
Q

The slant portion of the TSI determines if the organism is able to ferment _____.

A

Sucrose/Lactose

106
Q

Which portion of the TSI determines if the organism is a sucrose/lactose fermenter?

A

Slant

107
Q

Which portion of the TSI is aerobic?

A

Slant

108
Q

Reactions on TSI Agar

Slant: Acid (yellow)
Butt: Acid (yellow)
A/A

A

Lactose/Sucrose and Glucose Fermenter

109
Q

Reactions on TSI Agar

Slant: Alkaline (red)
Butt: Acid (yellow)
K/A

A

Glucose Fermenter

110
Q

Reactions on TSI Agar

Slant: Alkaline (red)
Butt: Alkaline (red)
K/K

A

No fermentation

It means that the organism is not a member of the Enterobacteriaceae Fam

111
Q

Interpret the TSI Result

Slant: Alkaline (red)
Butt: Acid (yellow)
H2S Production: +

A

K/A, H2S

112
Q

For H2S production to occur, it requires an _____ environment.

A

acidic

113
Q

What is the indicator for gas production in TSI?

A

Formation of bubbles or spliiting (space) of the medium in butt

114
Q

_____ is indicated by the formation of bubbles or splitting (space) of the medium in butt.

A

Gas production

115
Q

H2S producing organisms in TSI agar

A

MNEMONIC: SPACE
* Shigella
* Proteus
* Arizona
* Citrobacter
* Edwardsiella

116
Q

Which Biochemical Test?

To determine the ability of an organism to produce β-Galactosidase

A

Ortho-Nitrophenyl-β-D-Galactopyranoside Test (ONPG)

117
Q

What is the purpose of Ortho-Nitrophenyl-β-D-Galactopyranoside Test (ONPG)?

A

To determine the ability of an organism to produce β-Galactosidase

118
Q

____ hydrolyzes ONPG.

A

β-Galactosidase

119
Q

β-Galactosidase hydrolyzes ONPG into _______.

A

galactose and o-nitrophenol

120
Q

The colorless compound in ONPG test

A

ONPG

121
Q

The yellow-colored compound in ONPG test

A

galactose and o-nitrophenol

122
Q

If the organism is a non-lactose fermenter, the ONPG is _____.

A

colorless

123
Q

If the organism is a lactose fermenter, the ONPG is _____.

A

yellow

124
Q

Positive results for ONPG test can generally be seen within ______.

A

6 hours

125
Q

Steps in performing ONPG test

A
  1. Inoculate the organism in the tube containing 0.85% sterile saline.
  2. Place ONPG disk
  3. Incubate for 4 hours at 37 C
  4. Observe color change
126
Q

The ONPG tube contains ______.

A

0.85% sterile saline

127
Q

Incubation period for ONPG test

A

4 hours at 37 C

128
Q

Tests Under Glucose Metabolism and its Metabolic Products

A
  • Methyl Red
  • Voges-Proskauer
129
Q

Which pathway is utilized for Methyl Red Test?

A

Mixed Acid Fermentation Pathway

130
Q

If glucose is metabolized by the Mixed Acid Fermentation Pathway, ____ are produced, which results in a low pH.

A

stable acid end-products

131
Q

If glucose is metabolized by the Mixed Acid Fermentation Pathway, stable acid end-products are produced, which results in a ____.

A

low pH (4.4)

132
Q

Reagent for MR Test

A

Methyl Red

133
Q

Positive result for MR Test

A

Red color

134
Q

Negative result for MR Test

A

Yellow color

135
Q

Incubation period for MRVP Test

A

48 hours at 35-37 C

136
Q

Enumerate the steps for MR Test

A
  1. Inoculate organism in MRVP Broth
  2. Incubate for 48 hours at 35-37 C
  3. Divide the tubes into two (1 vor VP)
  4. Add MR reagent
  5. Observe color change
137
Q

Which Biochemical Test?

To determine the ability of an organism to convert acid products into acetoin and 2,3-butanediol.

A

Voges-Proskauer Test

138
Q

Purpose of VP Test

A

To detect the organism’s ability to convert acid products to acetoin and 2,3-butanediol.

139
Q

VP test determines the ability of an organism to convert acid products to ________.

A

acetoin and 2,3-butanediol

140
Q

Which pathway is used for VP Test?

A

Butylene Glycol Pathway

141
Q

It is added as a catalyst or color intensifier for VP Test.

A

α-naphthol

142
Q

α-naphthol function in VP Test

A

Catalyst and Color intensifier

143
Q

Reagent for VP Test

A

40% KOH or NaOH

144
Q

Positive result for VP Test

A

Red color

145
Q

Negative result for VP Test

A

Yellow color

146
Q

Enumerate the steps for VP Test

A
  1. Inoculate organism in MRVP Broth
  2. Incubate for 48 hours at 35-37 C
  3. Divide the tubes into two (1 vor VP)
  4. Add α-naphthol
  5. Add 40% KOH or NaOH
  6. Observe color change
147
Q

Amino Acid Utilization Tests

A
  • Lysine Iron Agar (LIA)
  • Phenylalanine Deaminase Test (PAD)
148
Q

Which Biochemical Test?

To differentiate gram (-) bacilli based on decarboxylation or deamination of lysine and the formation of hydrogen sulfide (H2S).

A

Lysine Iron Agar (LIA)

149
Q

Purpose of Lysine Iron Agar (LIA)

A

To differentiate gram (-) bacilli based on decarboxylation or deamination of lysine and the formation of hydrogen sulfide (H2S)

150
Q

pH indicator for LIA

A

Bromcresol purple

151
Q

The butt portion of the LIA determines if the organism is able to _____.

A

Decarboxylate lsyine

152
Q

Which portion of the LIA determines if the organism can decarboxylate lysine?

A

Butt

153
Q

The slant portion of the LIA determines if the organism is able to _____.

A

Deaminate lysine

154
Q

Which portion of the LIA determines if the organism can deaminate lysine?

A

Slant

155
Q

(+) result for Lysine Deaminase

A

Burgundy/Red color

156
Q

(-) result for Lysine Deaminase

A

Purple color

157
Q

(+) result for Lysine Decarboxylase

A

Purple color

158
Q

(-) result for Lysine Decarboxylase

A

Yellow color

159
Q

When the butt portion of LIA turns purple, it means that ____ is produced.

A

Cadaverine

160
Q

It neutralizes the organic acid fromed during glucose fermentation

A

Cadaverine

161
Q

What does Cadaverine do?

A

It It neutralizes the organic acid fromed during glucose fermentation

162
Q

When the butt portion of LIA turns yellow, it means that _____.

A

Glucose is fermented

163
Q

How is LIA performed?

A
  1. Using an inoculating needle, inoculate LIA by TWICE stabbing through the center of the medium to the bottom of the tube and then streaking the slant.
  2. Cap the tube tightly and incubate for 18-24 hours at 35-37 C.
164
Q

Reactions on LIA

Slant: Alkaline (purple)
Butt: Alkaline (purple)
K/K

A

Lysine decarboxylation and no fermentation of glucose

165
Q

Reactions on LIA

Slant: Alkaline (purple)
Butt: Acid (yellow)
K/A

A

Glucose fermentation

166
Q

Reactions on LIA Agar

Slant: Red
Butt: Acid (yellow)
R/A

A

Lysine deamination and glucose fermentation

167
Q

Deaminase (+) members of Enterobacteriaceae Family

A

ACRONYM: PPM
* Proteus spp.
* Providencia spp.
* Morganella spp.

168
Q

H2S (+) members of Enterobacteriaceae in LIA

A

ACRONYM: SACE
* Salmonella spp.
* Arizona spp.
* Citrobacter spp.
* Edwardsiella spp.

169
Q

Which Biochemical Test?

To determine whether an organism possesses the enzyme that deaminates phenylalanine to phenylpyruvic acid.

A

Phenylalanine Deaminase Test (PAD)

170
Q

Purpose of PAD

A

To determine whether an organism possesses the enzyme that deaminates phenylalanine to phenylpyruvic acid

171
Q

Which enzyme deaminates phenylalanine?

A

Phenylalanine deaminase

172
Q

When phenylalanine is deaminated, it produces _____.

A

Phenylpyruvic acid

173
Q

(+) result for PAD

A

Green color

174
Q

How is PAD performed?

A
  1. Inoculate a bacterial colony over the surface of the slant.
  2. After incubation, add 10% FeCl3
  3. Observe color change
175
Q

PAD contains ____.

A

0.2% concentration of Phenylalanine

176
Q

What reagent is used for PAD?

A

10% FeCl3

177
Q

Which medium is used for SIM?

A

SIM agar

178
Q

What type of agar is used for SIM according to consistency?

A

semi-solid

179
Q

What are the 3 factors that we observe in SIM?

A
  • Sulfide production
  • Indole production
  • Motility
180
Q

Sulfide production in SIM agar is indicated by the presence of _______.

A

black precipitate

181
Q

Purpose of Indole in SIM

A

To determine which organisms possess the enzyme Tryptophanase

182
Q

Which enzyme deaminates Tryptophan?

A

Trytophanase

183
Q

What does Trytophanase do?

A

It is an enzyme that deaminates Trytophan

184
Q

(-) result for Indole in SIM

A

Pink color

185
Q

What are the intermediate degradation products when Tryptophan is deaminated?

A

Indole, pyruvic acid, and ammonia

186
Q

What is the reagent used for SIM?

A

0.5 mL Ehrlich’s or Kovac’s Reagent

187
Q

(+) result for Indole in SIM

A

Presence of a red ring

188
Q

Motility in SIM agar is indicated by _______.

A

Cloudiness or Turbidity of solution

189
Q

Which medium is used for Citrate Utilization?

A

Simmon’s Citrate Agar

190
Q

Which is used as a sole carbon source by organisms (+) for Citrate Utilization?

A

Sodium citrate

191
Q

Which is used as a sole nitrogen source by organisms (+) for Citrate Utilization?

A

Ammonium salts

192
Q

pH indicator for Citrate Utilization

A

Bromthymol blue

193
Q

(+) result for Citrate Utilization

A

Blue or growth

194
Q

(-) result for Citrate Utilization

A

Green color

195
Q

Incubation period for Citrate Utilization

A

35-37 for 7 days

196
Q

______ hydrolyzes Urea

A

Urease

197
Q

What does Urease do?

A

Hydrolyze urea

198
Q

Urease hydrolyze urea to form ______.

A

Ammonia, water, and CO2

199
Q

Which medium is used for Urease Test?

A

Christensen’s Urea Agar

200
Q

(+) result for Urease Test

A

Magenta (pink) color

201
Q

What is the pH of the (+) result for Urease Test?

A

8.1

202
Q

(-) result for Urease Test

A

No change in color (remains light orange)

203
Q

What is the original color of the medium used for Urease Test?

A

Light orange (pH 6.1)

204
Q

Rapid urease producers

A

ACRONYM: PPM
* Proteus spp.
* Providencia spp.
* Morganella spp.

205
Q

Slow urease producers

A

ACRONYM: CKEYS
* Citrobacter spp.
* Klebsiella spp.
* Enterobacter spp.
* Yersinia spp.
* Serratia spp.

206
Q

Which Biochemical Test?

To differentiate organisms based on the production of deoxyribonuclease

A

DNA Hyrolysis Test (DNAse Test Agar)

207
Q

Purpose of DNA Hydrolysis Test

A

To differentiate organisms based on the production of deoxyribonuclease

208
Q

(+) result for DNAse Test

A

Colorless

209
Q

(-) result for DNAse Test

A

Green color

210
Q

Which organisms are (+) DNAse Test?

A
  • Serratia spp.
  • Staphylococcus aureus
  • Moraxella catarrhalis
211
Q

Which Biochemical Test?

To determine the ability of an organism to produce gelatinase

A

Gelatin Liquefaction

212
Q

Purpose of Gelatin Liquefaction

A

To determine the organism’s ability to produce gelatinase

213
Q

A proteolytic enzyme that breaks down gelatin into amino acids

A

Gelatinase

214
Q

What does gelatinase do?

A

Break down gelatin into amino acids

215
Q

Gelatinase breaks down gelatin into _______.

A

amino acids

216
Q

(+) result for Gelatin Liquefaction

A

Liquefaction of gelatin

217
Q

Which is used as a sole carbon source by organisms (+) for Malonate Utilization?

A

Malonate

218
Q

Which is used as a nitrogen source by organisms (+) for Malonate Utilization?

A

Ammonium sulfate

219
Q

pH indicator for Malonate Utilization

A

Bromthymol blue

220
Q

(+) result for Malonate Utilization

A

Blue color

221
Q

(-) result for Malonate Utilization

A

Green color

222
Q

Which Biochemical Test?

To determine the ability of an organism to reduce nitrate to nitrite and reduce nitrite to nitrogen gas.

A

Nitrate and Nitrite Reduction

223
Q

Purpose of Nitrate and Nitrite Reduction

A

To determine the ability of an organism to reduce nitrate to nitrite and reduce nitrite to nitrogen gas.

224
Q

What is the reagent used for Nitrate and Nitrite Reduction?

A
  • N,N-dimethyl-α-naphthylamine
  • Sulfanilic acid
225
Q

The reagent used for Nitrate and Nitrite Reduction is added after ______.

A

24 hours of incubation

226
Q

(+) result for Nitrate and Nitrite Reduction

A

Red color

227
Q

(-) result for Nitrate and Nitrite Reduction

A

Yellow color

228
Q

The red color in Nitrate and Nitrite Reduction indicates the presence of _____.

A

nitrite

229
Q

Which Biochemical Test?

To determine the presence of cytochrome oxidase

A

Oxidase Test

230
Q

Purpose of Oxidase Test

A

To determine the presence of cytochrome oxidase

231
Q

What is the reagent used for Oxidase Test?

A

0.5% or 1% of tetramethyl-p-phenylenediamine dihydrochloride

232
Q

(+) result for Oxidase Test

A

Lavender color within 10 to 15 seconds

233
Q

The (+) result for Oxidase Test appears within ______.

A

10 to 15 seconds

234
Q

Measure amount of antimicrobial agent in serum or body fluid

A

Antimicrobial Concentration Test

235
Q

Measure of lowest concentration of antimicrobial agent that kills a bacterial isolate.

A

Minimum Bactericidal Concentration Test

236
Q

Measure of highest dilution or titer of a patient’s serum

A

Serum Bactericidal Test

237
Q

Measure of susceptibility of a bacterial isolate to a combination of two or more antimicrobial agents.

A

Synergy Test

238
Q

Measure of rate of killing of bacteria by an antimicrobial agent

A

Time-kill Assay

Bacteriology (17 decks)

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