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Lab 2 Flashcards

1
Q

Catalase:
What is the chemical equation for the reaction that’s occurring?

A

2H2O2 -> 2H2O + O2

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2
Q

In exercise 5.6, what enzyme is being evaluated?

A

Catalase

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3
Q

Catalase:
What types of bacteria will have catalase?

A
  • Obligate aerobe
  • Facultative anaerobe
  • Microaerophile
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4
Q

What observation indicates a positive catalase test? Negative catalase test?

A

Positive catalase = bubbles
Negative catalase = no bubbles

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5
Q

Mannitol Salt Agar is what type of media?

A

Selective and Differential

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6
Q

What is the purpose of the salt in Mannitol Salt Agar?

A

It selects for growth in the presence of salt

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7
Q

What is the purpose of the mannitol in Mannitol Salt Agar?

A

It differentiates for fermentation of mannitol

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8
Q

What is the pH indicator used in Mannitol Salt Agar?

A

Phenol red

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9
Q

Mannitol Salt Agar:
What observation indicates a positive fermentation result? Negative fermentation result?

A

+ fermentation = yellow growth/halo (media)

negative fermentation = red growth/no halo (media)

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10
Q

What type of media is the nutrient agar in Mannitol Salt Agar?

What is the purpose of the nutrient agar plate using the same bacteria?

A
  1. Complex
  2. Control
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11
Q

Give an example of a bacteria that will grow on MSA. Name one that won’t.

A

One that will: Staphylococcus aureus
One that won’t: E. coli

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12
Q

What specific bacteria is this media (Mannitol Salt Agar) primarily used to detect?

A

Staphylococcus aureus

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13
Q

MacConkey Agar
Which type of media is this?

A

Selective and Differential

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14
Q

MacConkey Agar
What carbohydrate is present in this media?

A

Lactose

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15
Q

MacConkey Agar
What is the purpose of crystal violet?

A

Inhibits G+

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16
Q

MacConkey Agar
What is the pH indicator?

A

Neutral red

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17
Q

MacConkey Agar
What observation indicates a positive (lactose) fermentation result? Negative?

A

+ = pink colonies, lactose fermentation
- = cream colonies, no lactose fermentation

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18
Q

MacConkey Agar
What type of media is the nutrient agar?

What is the purpose of a nutrient agar plate with the same bacteria?

A
  1. Complex
  2. Control
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19
Q

Eosin Methylene Blue Agar
What type of media is this?

A

Selective and Differential

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20
Q

Eosin Methylene Blue Agar
What carbohydrate is present in this media?

A

Lactose

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21
Q

Eosin Methylene Blue Agar
What is the purpose of eosin Y and methylene blue dyes?

A

Inhibits G+ AND reacts with lactose fermenters (indicator)

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22
Q

Eosin Methylene Blue Agar
What observation indicates a positive fermentation result? Negative fermentation result?

A

+ = pink –> metallic green colonies (is a fecal coliform)

negative = cream, (not a fecal coliform)

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23
Q

Eosin Methylene Blue Agar
What specific group of bacteria should grow well on this media?

A

Fecal coliform

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24
Q

Eosin Methylene Blue Agar
What type of media is the nutrient agar?

What is the purpose of a nutrient agar plate with the same bacteria?

A
  1. Complex
  2. Control
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25
Bile Esculin Agar Which type of media is this?
Selective and Differential
26
Bile Esculin Agar What is the purpose of the bile?
Added to separate Group D strep from Non-Group D strep
27
Bile Esculin Agar What is the purpose of ferric citrate?
Reagent indicating a positive result
28
Bile Esculin Agar What enzyme is being evaluated?
Esculinase
29
Bile Esculin Agar What observation indicates a positive test? Negative test?
+ = black, has esculin, works in presence of bile negative = tan, no esculin, no bile
30
Bile Esculin Agar What specific group of bacteria should grow well on this media?
Group D Strep and Enterococci
31
Blood Agar Which type of media is this?
Enriched and Differential
32
Blood Agar What is the name of the exotoxin being evaluated?
Hemolysin
33
Blood Agar What is the purpose of the streak-stab technique?
Streak = to isolate colonies Stab = anaerobic environment
34
Blood Agar What is the difference between beta, alpha, and gamma hemolysis? Be able to recognize the difference between the various forms of hemolysis.
Alpha = partial breakdown Gamma = no breakdown Beta = complete breakdown
35
Blood Agar What is meant by fastidious?
Hard to grow
36
Bacitracin/Novobiocin Define the “zone of inhibition”
Diameter of space where growth is inhibited
37
Bacitracin/Novobiocin What is the mechanism of action for Bacitracin? Novobiocin?
Bacitracin = inhibits cell wall Novobiocin = inhibits DNA gyrase
38
Bacitracin/Novobiocin What is the necessary zone of inhibition for bacitracin to be considered susceptible/resistant?
Susceptible = > 10 mm (greater than 10 mm) Resistant = < 10 mm (less than 10 mm)
39
Bacitracin/Novobiocin What is the necessary zone of inhibition for novobiocin to be considered susceptible/resistant?
S = >16 mm R = < 16 mm
40
Kirby Bauer What is the specific name of the agar used in this test?
Muller Hinton Agar
41
Kirby Bauer Define the “minimum inhibitory concentration”. Where is this located on the plate?
The junction where the concentration of the antibiotic became too low to inhibit the growth
42
Kirby Bauer What is meant by Susceptible? Intermediate? Resistant?
S = antibiotic works I = antibiotic may work R = antibiotic does not work
43
Phenol Red Broth Which type of media is this?
Differential
44
Phenol Red Broth What is the pH indicator used in this test?
Phenol red
45
Phenol Red Broth What observation indicates a positive fermentation result? Negative result?
+ fermentation = yellow, aka A/G or A/- - fermentation = red
46
Phenol Red Broth What observation indicates a positive deamination result? Negative result?
+ deamination = pink - deamination = red
47
Phenol Red Broth What is the purpose of the Durham tube?
Captures CO2
48
Phenol Red Broth Know the symbols (A, G, K, -) and be able to use these to describe a phenol red tube.
A= yellow G= bubble K= pink - = red or no airbubble
49
A/-
yellow, no airbubble
50
A/G
yellow, air bubble
51
-/-
red, no airbubble
52
K
pink
53
Methyl Red and Voges Proskauer Tests Which type of media is this?
Differential
54
Methyl Red and Voges Proskauer Tests What does the Methyl Red test determine?
Mixed acid fermentation
55
Methyl Red and Voges Proskauer Tests What does the Voges Proskauer test determine?
Acetoin production
56
Methyl Red and Voges Proskauer Tests What observation indicates a positive Methyl Red test? Negative result?
+ = cherry red - = yellow/orange
57
Methyl Red and Voges Proskauer Tests What observation indicates a positive Voges Proskauer test? Negative result?
+ = wine red - = copper
58
Methyl Red and Voges Proskauer Tests What reagents are added to test for MR?
Methyl red indicator
59
Methyl Red and Voges Proskauer Tests What reagents are added to test for VP?
Naphthol and Potassium hydroxide
60
Decarboxylation Tests What type of media is this?
Differential
61
Decarboxylation Tests What is the specific name of the media used?
Moller's Decarboxylase Broth
62
Decarboxylation Tests What is the pH indicator used in this test?
Bromocresol purple
63
Decarboxylation Tests What is the incubation period?
96 hours
64
Decarboxylation Tests What three amino acids are being tested?
Lysine, Arginine, Ornithine
65
Decarboxylation Tests What observation indicates no fermentation and no decarboxylation?
tan
66
Decarboxylation Tests What observation indicates fermentation but no decarboxylation?
yellow
67
Decarboxylation Tests What observation indicates decarboxylation?
purple
68
Decarboxylation Tests What is the end product of decarboxylation?
CO2
69
Decarboxylation Tests What's the purpose of mineral oil
Promotes fermentation
70
Deamination Test What type of media is this?
Differential
71
Deamination Test What enzyme is present in bacteria that are positive?
Phenylalanine deaminase
72
Deamination Test What is the end product of deamination?
NH3
73
Deamination Test What reagent is used in this test?
Ferric chloride
74
Deamination Test What observation indicates a positive test? A negative test?
+ = green - = yellow
75
SIM What type of media is this?
Differential
76
SIM What 3 things are assessed in a single SIM test?
Sulfur reduction, Indole production, and Motility
77
SIM What is the purpose of Fe in this media?
Reagent indicating a positive result for Sulfer reduction
78
SIM What enzyme is present in a bacteria if it reduces sulfur?
Cysteine desulfurase
79
SIM What enzyme is present in a bacteria if it is indole positive?
Tryptophanase
80
SIM What reagent is used to determine if indole positive?
Kovac's reagent
81
SIM What observation indicates a positive sulfur reduction result? Negative result?
+ = black - = tan
82
SIM What observation indicates a positive indole result? Negative result?
+ = red layer on top - = yellow layer on top
83
SIM What observation indicates a positive motility result? Negative result?
+ = growth radiates from stab line - = defined stab line
84
SIM How else can motility be assessed?
Wet mount
85
Citrate Utilization Test What type of media is this?
Differential
86
Citrate Utilization Test What enzyme must the bacteria have if it is citrate positive?
Citrate permease
87
Citrate Utilization Test What provides a carbon source in this media? Nitrogen source?
Carbon = Citrate Nitrogen = Ammonium
88
Citrate Utilization Test What is the pH indicator?
Bromothymol blue
89
Citrate Utilization Test What is the purpose in using an inoculating needle instead of a loop?
To avoid heavy inoculum which would cause a false positive
90
Citrate Utilization Test What observation indicates a positive test result? Negative test result?
+ for citrate = blue or green with growth - for citrate = green with no growth
91
Beta looks like
a fried egg with halo around
92
Alpha looks
green gray with a very slight halo
93
Gamma has
no halo, just a colony

Microbiology (17 decks)

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