Final Prep Lab Exam 2 Flashcards
Lab Quiz 3, Lab Quiz 4, Protozoan Table, SG, +
1
Q
What is the purpose of the decarboxylase test?
5-11: Decarboxylase
A
To determine whether or not bacteria can decarboxylate lysine or ornithine
2
Q
What is the purpose of the deaminase test?
5-12: Deaminase
A
To determine whether bacteria can deaminate phenylalanine
3
Q
What is the purpose of the casease test?
5-16: Casease
A
To determine whether bacteria can hydrolyze casein
4
Q
What is the purpose of the urease test?
5-18 Urease
A
To determine if bacteria can hydrolyze urea
5
Q
What is the purpose of the TSI agar test?
5-21: TSI Agar H2S test
A
To differentiate bacteria on the basis
of glucose fermentation, lactose fermentation, sucrose fermentation, and sulfur reduction
6
Q
What is the purpose of the oxidase test?
5-7: Oxidase
A
To test bacteria for oxidase enzyme
7
Q
What is the purpose of the catalase test?
5-6: Catalase
A
To test bacteria for the catalase enzyme
8
Q
What is the purpose of the anaerobic jar test?
2-8: Anaerobic Jar
A
To determine the oxygen requirements of an organism
9
Q
What is the name of the medium?
5-11: Decarboxylase
A
Lysine/ornothine broth
- LDC or ODC
10
Q
What is the substrate, bacterial enzyme, and end product?
5-11: Decarboxylase
A
Substrate: Lysine or Ornothine
Bacterial Enzyme: Lysine or Ornothine Decarboxylase (endoenzyme)
End Products: Cataverine or putrescine (alkaline diamines) + CO2 g
11
Q
What is the appearance of a positive/negative?
5-11: Decarboxylase
A
Positive: Purple/gray
Negative: Yellow
12
Q
What is the reagent and pH indicator?
5-11: Decarboxylase
A
- None
- Bromocresol purple
13
Q
What else is important about this test? (4)
5-11: Decarboxylase
A
- Results cannot be read before 48H due to pH bounce
- Anaerobic enzymes (oil)
- Decarboxylation is anaerobic (oil used)
- Glucose is used first then acids which activate decarboxylase enzymes
14
Q
What is the name of the medium?
5-12: Deaminase
A
Phenylalanine agar
15
Q
What is the substrate, bacterial enzyme, and end product?
5-12: Deaminase
A
Substrate: Phenylalanine
Bacterial enzyme: Phenylalanine deaminase (endoenzyme)
End product: Ammonia + phenylpyruvic acid
16
Q
What is the appearance of a positive/negative?
5-12: Deaminase
A
Positive: Green
Negative: Yellow
17
Q
What is the reagent and pH indicator?
5-12: Deaminase
A
Reagent: Ferric Chloride (FeCl3) (indicates phenols)
pH indicator: None
18
Q
What else is important about this test?(2)
5-12: Deaminase
A
- pH products neutralize eachother
- Aerobic enzyme
19
Q
What is the name of the medium?
5-16: Casease
A
Milk agar
20
Q
What is the substrate, bacterial enzyme and end products?
5-16: Casease
A
Substrate: Casein
Bacterial enzyme: Casease (exoenzyme)
End products: AA + Polypeptides
21
Q
What is a positive/negative result?
5-16: Casease
A
Positive: Clear zone
Negative: White
22
Q
Are there reagents or pH indicators?
5-16: Casease
A
None
23
Q
What is the name of the medium?
2-8: Anaerobic Jar
A
Nutrient agar
24
Q
What else is important about this test?(1)
5-16: Casease
A
- Both + and - organisms still grow
25
What is the name of the medium?
## Footnote
5-18 Urease
Urea tablet
26
What is the substrate, bacterial enzyme, and end products?
## Footnote
5-18 Urease
Substrate: Urea
Bacterial enzyme: Urease
End products: Ammonia + CO2 g
27
What is a positive/negative result?
## Footnote
5-18 Urease
Positive: Pink
Negative: Yellow
28
What are the reagents an pH indicators?
## Footnote
5-18 Urease
None
Phenol Red
29
What else is important about this test?(2)
## Footnote
5-18 Urease
- Ammonia burns mucous membranes and neutralizes stomach acid
- *H. pylori*
30
What is the name of the medium?
## Footnote
5-21: TSI Agar H2S test
TSI agar
31
What are the substrates, bacterial enzymes, and end products?
## Footnote
5-21: TSI Agar H2S test
Substrates: Cystine + Sodium thiosulfate
Bacterial enzyme: Cystine desulfurase + Thiosulfate reductase (endoenzymes)
End product: H2S
32
What is a positive/negative result?
## Footnote
5-21: TSI Agar H2S test
Positive: Any black
Negative: No Black
33
What is the reagent and H2S indicator?
## Footnote
5-21: TSI Agar H2S test
No reagent
Ferrous ammonium sulfate
34
What else is important to consider?(1)
## Footnote
5-21: TSI Agar H2S test
Black color indicates an acidic pH
35
What is the name of the medium?
## Footnote
5-21: TSI Agar pH test
TSI agar
36
What are the substrates, bacterial enzymes, and end products?
## Footnote
5-21: TSI Agar pH test
Substrates: Glucose, Lactose, Sucrose
Bacterial enzymes: Various endoenzymes
End products: Acids
37
What does a positive/negative result look like?
## Footnote
5-21: TSI Agar pH test
Positive: Some yellow (glucose only)
Positive: All yellow (glucose plus at least one dissacharide)
Negative: No yellow or black
38
What are the reagents and pH indicator used?
## Footnote
5-21: TSI Agar pH test
None
Phenol Red
39
What else is important about this test?(1)
## Footnote
5-21: TSI Agar pH test
- In glucose only ferm. (K/A slant) glucose was in low % and runs out, peptones are then used aerobically
40
What is the name of the medium?
## Footnote
5-7: Oxidase
Nutrient agar
41
What is the substrate, bacterial enzyme, and end product?
## Footnote
5-7: Oxidase
Substrate: O2
Bacterial enzyme: Cytochrome C oxidase (endoenzyme)
End product: H2O
42
What is a positive/negative result?
## Footnote
5-7: Oxidase
Positive: Red/pink
Negative: No change
43
What is the reagent and pH indicator?
## Footnote
5-7: Oxidase
Oxidase reagent
None
44
What is the name of the medium?
## Footnote
5-6: Catalase
Nutrient agar
45
What is the substrate, bacterial enzyme, and end products?
## Footnote
5-6: Catalase
Substrate: H2O2
Bacterial enzyme: Catalase (endoenzyme)
End products: H2O + O2 g
46
What is a positive/ negative result?
## Footnote
5-6: Catalase
Positive: Bubbling
Negative: No bubbles
47
What reagent and pH indicator were used?
## Footnote
5-6: Catalase
H2O2
None
48
What is the substrate, chemical, and end product?
## Footnote
2-8: Anaerobic Jar
Substrate: O2
Chemical: Anaerogen chemical
End product: H2O
49
What is a positive/negative result?
## Footnote
2-8: Anaerobic Jar
Positive: Growth
Negative: No growth
50
What is the purpose of the thiobroth test?
## Footnote
2-7: Thiobroth
To determine the O2 requirements of
an organism
51
What is the name of the medium?
## Footnote
2-7: Thiobroth
Thio broth
52
What is the purpose of the sodium thioglycollate and L-cystine in the recipe?
## Footnote
2-7: Thiobroth
Remove O2 to make anaerobic environment (turned to water)
53
What do these results mean?
## Footnote
2-7: Thiobroth
- Growth only at top means the organism is a obligate aerobe
- Growth at top and in stab means the organism is a facultative anaerobe
- Growth only in the stab means obligate anaerobe
- Thin growth near the top means organism is a microaerophile
54
What enzyme is present in aerobic bacteria? Anaerobic?
## Footnote
2-7: Thiobroth
Superoxide dismutase - aerobic
Catalase - anaerobic
55
What are the results of this test?
## Footnote
5-21: TSI Agar HS2 and pH
- K/A H2S-
- A/A H2S-
- K/K H2S-
- K/K H2S-
- A/A H2S+
- K/A H2S+
56
Is protein deamination and decarboxylation an anaerobic or aerobic process?
Deamination - aerobic
Decarboxylation - anaerobic
57
What is the purpose of a Gelatinase test?
## Footnote
5-17: Gelatinase
Allows us to determine the ability of a microbe to produce gelatinases
## Footnote
Ex. Clostridium perfringens (Gangrene)
58
What is the purpose of a motility test?
## Footnote
5-28: Motility Test
To be able to detect bacterial motility which is an important differential characteristic
59
What is the purpose of temperature on microbial growth?
## Footnote
2-9: Effect of Temperature on Microbial Growth
A qualitative procedure to understand the effect of temperature on bacterial growth
## Footnote
Listeria monocytogenes is a psychrotroph that lived in your fridge and contaminates dairy products
60
What is the purpose of a nitrate reduction test?
## Footnote
5-8: Nitrate Reduction Test, First Step
This test tells us if bacteria can use nitrate as a final electron acceptor in anaerobic respiration. This is also to test if the **gram-negative rods** either do not reduce nitrate or reduce it beyond nitrite.
61
What is the purpose of the Kirby-Bauer Test?
## Footnote
7-3: Kirby-Bauer Test
To perform a culture and antibiotic sensitivity test on an organism
62
What is the purpose of the Membrane Filtration Test?
## Footnote
8-12: Membrane Filtration Test
To test water samples for the presence of coliform bacteria (presumptive)
63
What is the name of the medium?
## Footnote
5-17: Gelatinase
Gelatin Strip
64
What is the substrate, enzyme, and product(s)?
## Footnote
5-17: Gelatinase
Substrate: Gelatin
Enzyme: Exoenzyme Gelatinase
Products: AA + Polypeptides
65
What is the appearance of a positive test? Negative?
## Footnote
5-17: Gelatinase
Positive: Blue
Negative: No Change
66
What were the reagents used? pH indicator?
## Footnote
5-17: Gelatinase
None
67
What were the two bacteria that was used?
## Footnote
5-17: Gelatinase
2 type of bacteria:
– Pseudomonas aeruginosa (Pa) +
– E. coli (Ec) -
68
What was the medium of this experiment?
## Footnote
5-28: Motility Test
TTC Agar
69
What is the substrate, enzyme, and end product(s)?
## Footnote
5-28: Motility Test
Substrate: TTC
Enzyme: Various Reductases
Product: Formazan
70
What is the appearance of a positive? Negative?
## Footnote
5-28: Motility Test
Positive: Fuzzy Red Growth
Negative: Solid Non-fuzzy Red Line
71
What reagents and pH indicator were used?
## Footnote
5-28: Motility Test
None
72
What is the medium?
## Footnote
5-8: Nitrate Reduction Test, First Step
Nitrate Broth
73
What is the substrate, enzyme, and end product(s)?
## Footnote
5-8: Nitrate Reduction Test, First Step
Substrate: Nitrate (NO3)
Enzyme: Endoenzyme nitrate reductase
Product: Nitrite (NO2)
74
What is the appearance of a positive? Negative?
## Footnote
5-8: Nitrate Reduction Test, First Step
Positive: Red
Negative: Proceed to step 2
75
What reagent and pH indicators were used in step 1?
## Footnote
5-8: Nitrate Reduction Test, First Step
Reagent: Nitrate reagent A + B
pH indicator: None
76
What is the substrate, enzyme, and end product(s)?
## Footnote
5-8: Nitrate Reduction Test, Second Step
Substrate: Nitrate (NO3)
Enzyme: Many endoenzyme nitrate reductases
Products: Ammonium (NH4+, no gas) or NO,N2O,N2 gases (denitrification)
77
What is the appearance of a positive result? Negative?
## Footnote
5-8: Nitrate Reduction Test, Second Step
Positive: Clear after zinc
Negative: Red after zinc
78
What reagent and pH indicator were used?
## Footnote
5-8: Nitrate Reduction Test, Second Step
Reagent: Nitrate reagents A, B, Zinc
pH indicator: None
79
What is important about the zinc added in step two?
## Footnote
5-8: Nitrate Reduction Test, Second Step
If the broth turns red it is because nitrate was reduced by zinc. If it does not it means there was no nitrate(NO3) to reduce because it had already been reduced beyond nitrite (NO2)
80
What was the medium of this test? (5)
## Footnote
7-3: Kirby-Bauer Test
Mueller-Hinton Agar standardizes the following
- pH:7.4
- Soft agar
- 4mm depth agar for lateral diffusion
- Temp: 37 C
- Amount of drug
81
What were the three levels of susceptibility?
## Footnote
7-3: Kirby-Bauer Test
Sensitive: A normal dose is effective against bacteria
Intermediate: A higher than normal dose of an antibiotic is required
Resistant: No acceptable dose is effective
82
What is synergy, broad spectrum, narrow spectrum?
## Footnote
7-3: Kirby-Bauer Test
Synergy: when the effect of two drugs combines to be greater than their sum
Broad spectrum: Drugs that are effective against most bacteria typically reserved as final options as it can harm native flora
Narrow spectrum: Highly targetted drugs that are effective against a specific mecanism of bacterial growth. Must know what bacteria you are dealing with
83
What was the medium of this experiment?
## Footnote
8-12: Membrane Filtration Test
Endo agar or Nutrient Agar
84
What is the appearance of a positive? Negative?
## Footnote
8-12: Membrane Filtration Test
Positive:
Green Metalic Sheen (rapid lactose fermenter)
Dark pink/Red (slow lactose fermenter)
Negative:
Light Pink/Colorless (no lactose fermentation)
85
Entamoeba histolytica; Disease, Motility, Stages, Infectious Stage(s) and mode of Transmission.
86
Balantidium coli; Disease, Motility, Stages, Infectious Stage(s) and mode of Transmission.
87
Giardia lamlia (intestinalis); Disease, Motility, Stages, Infectious Stage(s) and mode of Transmission.
88
Trichomonas vaginalis; Disease, Motility, Stages, Infectious Stage(s) and mode of Transmission.
89
Trypanosoma brucei; Disease Motility, Stages, Infectious Stage(s) and mode of Transmission.
90
Toxoplasma gondii; Disease Motility, Stages, Infectious Stage(s) and mode of Transmission.
91
Plasmodium falciparum; Disease Motility, Stages, Infectious Stage(s) and mode of Transmission.
92
Entamoeba histolytica; Symptoms, Treatment, Diagnosis/Notes
93
Balantidium coli; Symptoms, Treatment, Diagnosis/Notes
94
Giardia lamblia (intestinalis); Symptoms, Treatment, Diagnosis/Notes
95
Trichomonas vaginalis; Symptoms, Treatment, Diagnosis/Notes
96
Trypanosoma brucei; Symptoms, Treatment, Diagnosis/Notes
97
Toxoplasma gondii; Symptoms, Treatment, Diagnosis/Notes
98
Plasmodium falciparum; Symptoms, Treatment, Diagnosis/Notes
99
What is this?
Entamoeba histolytica (cyst)
100
What is this?
Entamoeba histolytica (trophozoite)
101
What is this?
Balantidium coli (cyst)
102
What is this?
Balantidium coli (Trophozoite)
103
What is this?
Giardia lamblia (intestinalis) (cyst)
104
What is this?
Giardia lamblia (intestinalis) (trophozoite)
105
What is this?
Trichomonas vaginalis (Trophozoite)
106
What is this?
Trypanosoma brucei (Trypomastigote)
107
What is this?
Toxoplasma gondii (Trophozoite)
108
What is this?
Plasmodium falciparum (Ring stage, merozoites)
109
Enzymes called decarboxylases catalyze the removal of the _________________ from an amino acid.
## Footnote
5-11: Decarboxylase Test
Carboxyl group
110
Enzymes called deaminases catalyze the removal of the ________________ from an amino acid.
## Footnote
5-11: Decarboxylase Test
Amines
111
What is meant by the substrate of an enzyme?
## Footnote
5-11: Decarboxylase Test
The substrate of an enzyme is amino acid that has its variable group removed during the reaction resulting in the production of an amine or carboxyl group being released
112
Decarboxylases catalyze reactions that produce ________________ (pH) products.
## Footnote
5-11: Decarboxylase Test
Alkaline
113
The pH indicator bromocresol purple is ______________ at pH 6.8 and above and ______________ below pH 5.2.
## Footnote
5-11: Decarboxylase Test
Purple
Yellow
114
Why is mineral oil added to the decarboxylase broth tubes before incubation?
## Footnote
5-11: Decarboxylase Test
To seal off from oxygen and encourage fermentation
115
Why does the decarboxylase-positive tube have to turn yellow before it can turn purple?
## Footnote
5-11: Decarboxylase Test
- Accumulation of acidic end products will occur first
- Then low pH organisms will react to acidic enviornment and either produce decarboxylases or not resulting in positive (purple) or negative (yellow) results
116
Describe a positive result in this experiment and describe a negative result. What kind of pH is present in a + result and is present in a - result?
## Footnote
5-11: Decarboxylase Test
Positive: Purple, Alkaline, decarboxylases resulted in an increase in pH
Negative: Yellow, Acidic, lack of decarboxylases meant pH remained negative
117
Why is glucose included in the decarboxylase broth?* (Hint: answer is not “as a food source”)
## Footnote
5-11: Decarboxylase Test
- Low glucose concentration promotes fermentation lowering pH and causing proteases to activate (decarboxylase)
118
This decarboxylation test cannot be performed successfully on organisms that cannot ferment glucose. Explain why this is the case.*
## Footnote
5-11: Decarboxylase Test
- If the organism cannot lower the pH through fermentation the proteases will not be activated and **no color change will occur**
119
Cadaverine and putrescine are examples of compounds known as __________________.
## Footnote
5-11: Decarboxylase Test
Diamines
120
The names, cadaverine and putrescine, suggest that the compounds might be found in _______________, which they are, as a result of the decarboxylation of ________________ (what molecule) by bacteria.
## Footnote
5-11: Decarboxylase Test
- Rotting Flesh
- Lysine -> Cadaverine
- Ornothine -> Putrescine
121
What is phenylalanine (what type of monomer is it)?
## Footnote
5-12: Phenylalanine Deaminase
- Amino Acid substrate
122
Phenylalanine is part of an ingredient found in the popular artificial sweeteners known as _________________ or ___________________.
## Footnote
5-12: Phenylalanine Deaminase
Aspartane
Nutrasweet
123
The enzyme that some bacteria can produce that removes an amino group from phenylalanine is called ___________________________________.
## Footnote
5-12: Phenylalanine Deaminase
Phenylalanine Deaminase
124
The reagent that is added to bacterial growth on phenylalanine deaminase agar in order to determine if the enzyme has been produced, is __________________________.
## Footnote
5-12: Phenylalanine Deaminase
Ferric Chloride
125
Describe a positive result in the experiment and a negative result.
## Footnote
5-12: Phenylalanine Deaminase
- Green indicates positive as Phenolpyruvate is present
- Yellow indicates negative as no phenolpyruvate is present
- Note this is not a pH test as the phenyl pyruvate and ammonium cancel eachother's pH
126
Phenylalanine is broken down to _____________________ and _____________________.
## Footnote
5-12: Phenylalanine Deaminase
Ammonium
Phenylpyruvic Acid
127
Why can’t you use a pH indicator to detect phenylalanine deamination?
## Footnote
5-12: Phenylalanine Deaminase
Because the Phenylpyruvic acid (acid) and Ammonium (base) cancel eachother's pH
128
A green color results in this experiment if _______________________________ reacts with the reagent ________________________.*
## Footnote
5-12: Phenylalanine Deaminase
Phenylpyruvic Acid
Ferric Chloride
129
Like all amino acids, phenylalanine is a source of the two elements ______________ and _____________ for the bacteria.
## Footnote
5-12: Phenylalanine Deaminase
Nitrogen
Carbon
130
Write the chemical formula for an amine group (amino group).
## Footnote
5-12: Phenylalanine Deaminase
NH2
131
What is the difference between the deamination and the decarboxylation of an amino acid (Hint: think of oxygen requirements)?
## Footnote
5-12: Phenylalanine Deaminase
Decarboxylation occurs in anaerobic conditions
Deamination occurs in aerobic conditions
132
Urea can be hydrolyzed to carbon dioxide and ___________________ by bacteria that produce the enzyme ______________________________.
## Footnote
5-18: Urease Test
Ammonium
Urease
133
Urinary tract pathogens from the genus ______________________ can be distinguished from other enteric bacteria by their rapid urease activity.
## Footnote
5-18: Urease Test
Proteus
134
What other disease is caused by this organism? (Proteus)
## Footnote
5-18: Urease Test
Proteus mirabilis and Proteus vulgaris cause diaper rash
H. Pylori causes stomach ulcers
135
Urease-positive organisms break down urea to _______________, which ________________ the pH of the medium and changes the color of the pH indicator phenol red from _______________ to _______________.
## Footnote
5-18: Urease Test
Ammonium
Increases
Orange
Pink
136
Describe a positive urease test and a negative test (include the relative pH).
## Footnote
5-18: Urease Test
Pink: Urease was produced leading to release of ammonium as urea broke down (+), pH >8.4
Orange: (-) pH <8.4
Yellow: Organism was unable to produce urease and did not break down urea (-), pH <8.4
137
In order for a urease-positive organism to turn the urea broth pink, the organism must ___________________ the pH of the medium enough to overcome the effects of the __________________, potassium phosphate.
## Footnote
5-18: Urease Test
Increase
Buffer
138
The urease test is an important part of the identification of the organism _________________________ , that causes peptic ulcers.
## Footnote
5-18: Urease Test
H. pylori
139
How does this organism (H. pylori) survive stomach acid?
## Footnote
5-18: Urease Test
Rapid Urease production leads to ammonium production which can neutralize the stomach acid
140
A rapid urease test is performed on the ______________________ of patients with peptic ulcer symptoms.
## Footnote
5-18: Urease Test
majority
141
Why is it important that urease broth contain a buffer that can resist alkalinization of the medium from peptone metabolism?*
## Footnote
5-18: Urease Test
To avoid false positives from reversion of peptone metabolism
142
Ammonia is used by many bacteria as a source of the element ______________________.
## Footnote
5-18: Urease Test
Nitrogen
143
Bacteria use nitrogen, in order to make what two classes of macromolecules?*
## Footnote
5-18: Urease Test
Nucleic acids and Polypeptides
144
TSI is a differential medium that is useful in differentiating _______________________________________.
## Footnote
2-7: Triple Sugar Iron (TSI) agar
Fermentation
145
Triple Sugar Iron agar contains 3 sugars in its recipe. The monosaccharide ___________ is supplied in a low percentage (0.1%) while the disaccharide sugars ____________ and ____________ are provided in a higher percentage (1%).
## Footnote
2-7: Triple Sugar Iron (TSI) agar
Glucose
Lactose
Sucrose
146
The results of TSI tubes are recorded according to the pH of the __________ over the pH of the ________(e.g., K/A). The pH indicator in TSI is __________________ which is the color ______________ when it’s acidic and ______________ when it’s alkaline.
## Footnote
2-7: Triple Sugar Iron (TSI) agar
Slant
Butt
Phenol Red
Yellow
Red
147
Fermenters only capable of fermenting _______________ will run out of sugar within the first few hours during incubation. Explain what these organisms do next and what the results look like in both the slant and butt.
## Footnote
2-7: Triple Sugar Iron (TSI) agar
Glucose
- These organisms will then swap to peptone digestion which will turn the slant red while the anaerobic butt remains yellow
148
Fermenters capable of fermenting one or both disaccharides (sucrose and/or lactose) will never run out of sugar during the required 24-hour incubation. Explain what TSI slant looks like in this case.
## Footnote
2-7: Triple Sugar Iron (TSI) agar
- Because Fermentation will occur throughout the entire 24H period the slant and butt will both be yellow
149
Besides sugar, other substrates found in TSI agar include _____________ and ________________________. These substrates are a source of reducible ____________, and digestion of these substrates leads to the formation of H2S.
## Footnote
2-7: Triple Sugar Iron (TSI) agar
Cysteine
Sodium Thiosulfate
Sulfur
150
H2S is a colorless gas that smells like rotten eggs. It is visually detected when a black color (precipitate) forms by reacting with the iron-containing ingredient ___________________________________.
## Footnote
2-7: Triple Sugar Iron (TSI) agar
Ferrous ammonium sulfate
151
H2S can be made by certain species of sulfur-reducing bacteria. The formation of H2S requires a reducing environment where excess hydrogen is present, and the pH is _____________.
## Footnote
2-7: Triple Sugar Iron (TSI) agar
Acidic
152
Explain why a K/K [H2S +] result is not possible.
## Footnote
2-7: Triple Sugar Iron (TSI) agar
Because in order for the agar to be H2S+ it would require an acidic environment which is not possible if the tube is K/K
153
Enzymes that are released into the bacterial environment and work there are known as ______________________________.
## Footnote
2-7: Triple Sugar Iron (TSI) agar
Exoenzymes
154
Bacteria that produce protein-digesting (proteolytic) enzymes break down large ___________________ to smaller _____________________ or individual ____________________.
## Footnote
5-16: Casease Test
Proteins
Peptides
Amino Acids
155
Why do bacteria have to break down proteins in their environment (outside the cell) in order to use the proteins as a food source?
## Footnote
5-16: Casease Test
Because it is too big to be taken across the membrane and therefore needs to be broken down.
156
Why is milk opaque?* Why does the milk agar turn clear when an organism produces the casease enzyme?*
## Footnote
5-16: Casease Test
Casein is the protein that gives milk its white color but when it is broken down it becomes clear and less opaque
| Top line is Casease +
157
What is a polypeptide? What is the difference between a polypeptide and a peptide? Between a polypeptide and a protein? Between a peptide and an amino acid?
## Footnote
5-16: Casease Test
- A polypeptide is a long chain of amino acids
- A peptide is a shorter chain of amino acids
- A protein can be made of multiple polypeptides
- An amino acid is a monomer.
158
What is the difference between casein and pancreatic digest of casein?
## Footnote
5-16: Casease Test
- Casein is large bulky protein
- Pancreatic digest of casein has been broken down and is an accessible food source
159
Why are whole, undigested proteins (as opposed to peptones), not usually included in the microbiological growth media?*
## Footnote
5-16: Casease Test
Because they're often too large or hard to break down if the bacteria dont have the right exoenzymes. Food sources must be able to be digested and taken into the cell
160
Most nitrate-reducing bacteria contain the enzyme ________________________ and perform a single-step reduction of nitrate.
## Footnote
5-8 Nitrate Reduction
Nitrate Reductase
161
What is denitrification?
## Footnote
5-8 Nitrate Reduction
The loss of biologically available nitrogen; occurs by release of nitrogenous gas
162
Write the chemical formulas for nitrate, nitrite, potassium nitrate, ammonia, ammonium ion, molecular nitrogen, and nitric oxide.
## Footnote
5-8 Nitrate Reduction
Nitrate: NO3
Nitrite: NO2
Potassium Nitrate: KNO3
Ammonia: NH3
Ammonium ion: NH4+
Nitrogen: N2
Nitric Oxide: NO
163
Why is the conversion of nitrate to nitrite an example of reduction?
## Footnote
5-8 Nitrate Reduction
Because you go from NO3 to NO2 which is a gain in electrons for nitrogen as nitrogen's oxidation state goes from +5 to +3 (oxidation state going down is reduction)
164
Why is the conversion of nitrite to the ammonium ion an example of reduction?
## Footnote
5-8 Nitrate Reduction
Because you go from NO2 to NH4+ and the oxidation state goes from +2 to -3 which is reduction
165
Why do bacteria need nitrogen (which 2 macromolecules require nitrogen)? (2 answers)*
## Footnote
5-8 Nitrate Reduction
Nucleic acids and Peptides
166
Why are there Durham tubes in the nitrate broth?
## Footnote
5-8 Nitrate Reduction
Because if denitrification occurs, N2 gas will be produced
167
Explain thoroughly each of the following results in this experiment.
a. After incubation, turbid nitrate broth turns red when test reagents A and B are added.
b. After incubation, turbid nitrate broth does not turn red when reagents A and B are added.
c. A turbid tube that did not turn red when reagents A and B were added turns red when zinc is added.
d. A turbid tube that did not turn red when reagents A and B were added does not turn red when zinc is added.
e. There is gas in the Durham tube after incubation with a non-fermenting organism.
## Footnote
5-8 Nitrate Reduction
A. (+) Nitrate is present and bacteria did reduce nitrate
B. Zinc must be added to determine if zinc can reduce nitrate (-) or if no nitrite is present (+). Either no reduction or full reduction occured
C. (-) Red indicates bacteria did not reduce, the zinc did
D. (+) Bacteria were able to reduce nitrate broth and either underwent ammonification or underwent full nitrification
E. (+) Full denitrification occured resulting in gas in durham tube
168
Describe the results that would occur in an uninoculated control tube when reagents A and B are added to it?* Why?*
## Footnote
5-8 Nitrate Reduction
The tube would stay transparent as there is no nitrite to react with
169
What results should an uninoculated control tube give when ONLY zinc is added to it?* Why?*
## Footnote
5-8 Nitrate Reduction
The broth should remain transparent as the zinc is for reducing the broth but is not an indicator
170
What results should an uninoculated control tube give when reagents A, B, and zinc are added to it?* Why?*
## Footnote
5-8 Nitrate Reduction
The Tube will turn red because the zinc will reduce nitrate and the indicator will show the presence of nitrite
171
What do reagents A and B test for? What does the zinc test for?
## Footnote
5-8 Nitrate Reduction
- Reagents A and B test for nitrite presence
- Zinc test if reduction occured and will turn nitrate into nitrite if it has not already occured
172
Why is the conversion of nitric oxide to molecular nitrogen an example of reduction?
## Footnote
5-8 Nitrate Reduction
Because the electronegativity went from +2 to 0
173
After incubation, gas in the Durham tube in a tube inoculated with a non-fermenting organism means that _____________________ has occurred. Is this a + or a – test for nitrate reduction? What type of gas has been produced?
## Footnote
5-8 Nitrate Reduction
Denitrification
Positive
Nitrogen
174
What is the original source of nitrate in the nitrate broth? Write the formula for this compound.
## Footnote
5-8 Nitrate Reduction
KNO3
175
What are aerobic bacteria? (see textbook)
## Footnote
5-6 Catalase Test
Bacteria that require an oxygenated environment because they use oxygen as their final electron acceptor
176
What are aerotolerant bacteria? (see textbook)
## Footnote
5-6 Catalase Test
Bacteria that can grow in an oxygenated environment but prefer an anaerobic environment
177
What are facultative bacteria? (facultative anaerobes) (see textbook)
## Footnote
5-6 Catalase Test
Facultative anaerobes can grow better with oxygen but still grow at a slower rate in an anaerobic environment
178
Aerobic and aerotolerant bacteria produce enzymes capable of detoxifying 2 very potent cellular toxins, ___________________________ and __________________________.
## Footnote
5-6 Catalase Test
Superoxide dismutase
Catalase
179
The enzyme _____________________ catalyzes conversion of ______________________, the more lethal of the 2 compounds, to _________________________.
## Footnote
5-6 Catalase Test
Superoxide dismutase
Superoxide radicals
Hydrogen peroxide
180
The enzyme __________________ converts hydrogen peroxide to _____________ and _________________.
## Footnote
5-6 Catalase Test
Catalase
Water
Oxygen
181
What happens when hydrogen peroxide is added to a catalase-positive culture? What is the appearance of the catalase-negative culture when hydrogen peroxide is added?
## Footnote
5-6 Catalase Test
- The culture will fizz and bubble
- A catalase negative culture will not bubble when it encounters hydrogen peroxide
182
This test is most commonly used to differentiate members of the catalase-positive __________________________ from the catalase-negative __________________________.
## Footnote
5-6 Catalase Test
Micrococcaceae
Streptococcaceae
183
If an organism is catalase-negative, what does that tell you about its oxygen requirements?* Why?*
## Footnote
5-6 Catalase Test
It is anaerobic because it does not have a way to get rid of superoxide radicals
184
If an organism is catalase-positive, what does that tell you about its oxygen requirements?* Why?*
## Footnote
5-6 Catalase Test
It is aerobic as it has a way to get rid of harmful superoxide radicals
185
What is the morphology and gram reaction of the organism used in this experiment? Even before you performed the catalase test on this organism, you should suspect that it is catalase positive because:
## Footnote
5-6 Catalase Test
S. Epidermidis (Gram positive coccus) which lives on the skin and is an aerobe.
E. Faecalis (Gram positive coccus) which is found in the colon where there isn't much oxygen.
186
Would you expect bacteria that are facultative anaerobes to be catalase-positive or catalase-negative?* Why?*
## Footnote
5-6 Catalase Test
They should be catalase positive because using oxygen as an electron acceptor will lead to superoxide radical productions. This means bacteria must have a way to deal with them
187
The oxidase test that is useful in the presumptive identification of the gram-negative coccus _________________________. Name 2 diseases caused by species of this genus.
## Footnote
5-7 Oxidase Test
Neisseria
N. meningitidis causes meningitis
N. gonorrhoeae causes gonorrhea
188
Bacteria that belong to the family Pseudomonadaceae are oxidase __________________; bacteria that belong to the family Enterobacteriaceae are oxidase ________________________.
## Footnote
5-7 Oxidase Test
Positive
Negative
189
What does a positive oxidase test look like? Include the time frame.
## Footnote
5-7 Oxidase Test
A positive test will result in a red smear after 20 seconds
190
What does a negative oxidase test look like? (2 answers)*
## Footnote
5-7 Oxidase Test
No color change within 20sec
Color change (pink)after a minute due to reagent oxidation
191
If your bacteria turn pink after more than one minute has elapsed since the oxidase reagent was added, why is this happening?
## Footnote
5-7 Oxidase Test
The reagents are unstable and were oxidized independently given enough time
192
The quantitative sensitivity disk method of antibiotic sensitivity testing is called the _________________
method.
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
Kirby-Bauer
193
In this method, the diameter of the ___________________________ around the disk is measured to the
nearest _____________________ (unit).
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
Zone of inhibition
Milimeters
194
The inhibition zone diameter that is produced in this experiment will indicate the ___________________ of a bacterium to each antibiotic.
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
Sensitivity
195
How do you determine if an organism is susceptible to a particular antibiotic in this test? How do you determine if the organism is resistant?
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
The susceptibility zone is measured and compared to a document that states according to what antibiotic is being used a diameter under X is resistant and over X is susceptible
196
What will a negative test for antibiotic sensitivity look like? Describe such a result and explain what it means.
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
A negative would be shown as no ZOI or a small ZOI. This means that the antibiotic was unable to stop or kill the bacteria
197
What will a positive test for antibiotic sensitivity look like? Describe such a result and explain what it means.
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
A large ZOI that is greater than the susceptibility break point
ex. Breakpoint <10mm, actual D = 18mm
198
Why is it important that the sensitivity disks used in this experiment contain a specific, standardized amount of antibiotic?* How is this test standardized (i.e. what is standardized in this test)?(4)
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
- To ensure all results are reliable and safe for humans
- The agar is 4mm (thinner than usual) to promote lateral diffusion
- pH is kept to 7.2-7.4 to mimic blood pH
- Agar is incubated at 37 degrees C to mimic human body temp
- Agar is incubated for 18 hours to select for younger bacteria
199
Why is it important that the results of antibiotic sensitivity test guide treatment of bacterial infections?
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
It allows us to understand how different drugs interact with bacteria and what is an effective medication that could be used to adress a bacterial infection appropriately
200
Penicillin is an antibiotic produced by the mold ________________________ (genus), which is also responsible
for __________________________ (type of food).
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
Penicillium
Cheese
201
What is “intermediate susceptibility” to an antibiotic?* Under what conditions would it be appropriate to use an antibiotic to which a particular organism was intermediately susceptible?*
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
- When the ZOI is above resistant but below susceptibility
ex. R<5, I=6-8, S>9
- Appropriate if the person is allergic to other antibiotics or can be used with another drug for enhanced effects
202
True or false: All bacteria found within the clear area around the disks are dead. Why did you answer true or false?
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
False. There are bacteriostatic antibiotics which are not bacteriocidal. Often times with gram negative infections when they are lysed they release lipid-A which is toxic and can cause shock and even death. Therefore a bacteriostatic drug is better to pause development and allow the patient's body to fight the infection in a safer way
203
What is a broad-spectrum antibiotic? When would it be better to use a broad-spectrum antibiotic? Why?
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
A broad-spectrum antibiotic is an antibiotic that many bacteria are susceptible both gram positive and gram negative. Broad spectrum antibiotics are generally reserved as a last ditch effort as it also kills natural flora. Otherwise targetted antibiotics are usually more appropriate
204
What is a narrow spectrum antibiotic? When would it be better to use a narrow spectrum antibiotic? Why?
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
Narrow spectrum antibiotics are antibiotics that are effective at targetting a specific bacteria. This is effective when you know exactly what the bacterial infection is and will not affect your natural flora
205
What is drug synergy? What does plate look like if two drugs are synergistic?
## Footnote
7-3 Antibiotic Sensitivity Testing (Kirby-Bauer Method)
- Drug synergy is when antibiotics combine and have a greater effect together than their individual effects summed
- If the drugs synergize the 'halo' between the two drugs will be bigger than the halo around the drug itself
206
Name the causative agent (organism) of amoebic dysentery (amebiasis).
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Entamoeba histolytica
207
Amoebic dysentery is most common in areas with __________________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Poor water sanitation
208
Identification of the amoebic dysentery organism may be made by finding either trophozoites or _________________ in a _________________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Cysts
Stool Sample
209
Infection with the amoebic dysentery organism occurs when a human host ingests _______________ (stage) in _____________________________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
- Cyst
- Contaminated Food or Water
210
__________________ of the amoebic dysentery organism are shed in the feces and may _______________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
- Cyst
- Be infective
211
Cysts of the amoebic dysentery protozoan may persist in the original host, resulting in ____________________________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Asymptomatic Carriers
212
How does the organism that causes amoebic dysentery move through its environment?
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Psuedopods
213
The only ciliated human pathogen is (genus and species) __________________________________ and it causes the disease __________________________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
- Balantidium coli
- Balantidiasis
214
____________________ in sewage-contaminated water are the infective form of Balantidium coli.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Cysts
215
Most infections of Balantidium coli are asymptomatic, however it can cause the following symptoms in some patients:
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Diarrhea (bloody,invasive)
216
Name the organism that causes giardiasis.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Giardia lamblia (intestinalis)
217
Transmission of giardiasis typically involves:
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Fecal or oral transmission due to drinking river/lake water
218
What is the infective stage of the organism that causes giardiasis?
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Cyst
219
Diagnosis of giardiasis is made by identification of the protozoan trophozoites or ______________ in ____________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Cysts
Stool Sample
220
The STI/STD known as trichomoniasis is more common in ________________ than _________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Women
Men
221
Protozoal vulvovaginitis in humans is caused by (genus and species) ______________________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Trichomonas Vaginalis
222
Trichomonas is typically transmitted by _______________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Sexual transmission
223
The ____________________ is the only stage of the Trichomonas life cycle and moves by _______________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Trophozoite
Swimming
224
What drug is used to cure (treat) Trichomonas, Entamoeba, Balantidium, and Giardia?
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Flagyl
(metronidazole)
225
The genus of the organism that causes African trypanosomiasis, a disease commonly known as ______________________________, is __________________________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
African Sleeping Sickness
Trypanosoma
226
The intermediate host (vector) for African trypanosomiasis is the _______________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Tsetse fly
227
The stage of Trypanosomes that multiplies in the intermediate host is the ___________________, while the ___________________ stage multiplies in the human host.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Epimastigote
**Trypomastigote**
228
Which area or part of the body is affected during the advanced stages of infection that lead to coma and death in African Sleeping Sickness?
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
The Brain
229
Name a disease caused by Trypanosoma other than African sleeping sickness.* How is this disease transmitted?* In what part of the world is the disease most common?*
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
South America Sleeping Sickness
Transmitted by bug bite
South America
230
Name the genus and species of the 4 protozoans that cause malaria.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Plasmodium falciparum
Plasmodium malariae
Plasmodium ovale
Plasmodium vivax
231
The most severe form of malaria involves which organism? (genus and species)
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Plasmodium falciparum
232
The arthropod vector for malaria is the _____________________________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Anopheles Mosquito
233
For malaria, the ________________________ stage of the pathogen is introduced into a human by a bite by the arthropod vector.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Sporozoite
234
For malaria, the _____________________ stage are released from the ruptured liver cells in humans, enter the blood, and infect erythrocytes.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Merozoites
235
Name two drugs in current use in the treatment of malaria.*
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Quinine, chloroquine
236
The sexual phase of the life cycle of Toxoplasma occurs in the _______________ where ____________________ are produced and shed in the ____________________.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Cat intestines
Oocysts
Feces
237
The more serious form of toxoplasmosis involves:
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
An infection of a fetus across the placenta that can result in still birth
238
Fetal infection with toxoplasmosis may result in:
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Still birth
239
______________________ patients may suffer fatal complications from toxoplasmosis.
## Footnote
12-3: Examination of Common Protozoans of Clinical Importance
Immunocompromised or pregnant
240
Give 2 reasons why sodium sulfite and basic fuchsin are included in Endo agar.
## Footnote
8-12 Endo Agar
- They inhibit the growth of gram-positive bacteria
- They both test for lactose fermentation
241
Endo agar inhibits the growth of _______________________ bacteria.
## Footnote
8-12 Endo Agar
Gram positive
242
The fermentable carbohydrate in Endo agar is _____________________.
## Footnote
8-12 Endo Agar
Lactose
243
What will colonies of lactose fermenters look like growing on Endo agar?
## Footnote
8-12 Endo Agar
Lactose fermentation -> Acids -> If rapid fermenter green metalic sheen, If slow fermenter dark pink/red
244
What appearance is created in this agar by lactose-fermenting organisms that produce large amounts of acid?
## Footnote
8-12 Endo Agar
- A metalic sheen green on the top of the agar and black appearance from the back of the plate
245
Name one coliforms (genus and species) that produce large amounts of acids when grown on Endo agar.
## Footnote
8-12 Endo Agar
E. coli
246
What appearance will be created by lactose non-fermenters growing on Endo agar?
## Footnote
8-12 Endo Agar
Light pink/colorless growth
247
Bacteria that will grow on Endo agar are Gram _______.
## Footnote
8-12 Endo Agar
Negative
248
Endo agar is used to detect fecal contamination in water and dairy products. What is the connection between fecal contamination and the bacteria that produce a metallic sheen on this agar?*
## Footnote
8-12 Endo Agar
Water and milk are tested for because E.coli lives in the intestines and their presence signals fecal contamination. The metalic sheen growth on endo agar is a visual indicator that the bacteria was a lactose fermenter and is presumptively a fecal coliform
249
If an organism that cannot ferment lactose grows on Endo agar, what is it using as a food source?* What kind of pH would this organism be expected to produce in the medium?* What will the colonies of this kind of organism look like?*
## Footnote
8-12 Endo Agar
Peptones, this organism would have a alkaline pH from peptone digestion. This organism would grow in light pink or colorless colonies
- **It is important to note, nonfermenter could still be possible salmonella or shigella**
250
What will be the appearance of a presumptive coliform organism growing on this agar? Why?
## Footnote
8-12 Endo Agar
- Metalic sheen green if the organims is a rapid fermenter of lactose
- Dark pink/red if the organism is a slow fermenter of lactorse
251
If an organism will not grow on Endo agar, that is a presumptive indication that the organism is __________________.
## Footnote
8-12 Endo Agar
Gram Positive
252
Helicobacter pylori
Urease positive - causes ulcers
253
Pseudomonas aeruginosa
Gelatinase positive and strict (obligate) aerobe - causes skin infections in burn patients, lung infections in cystic fibrosis patients
254
Staphylococcus aureus
G+, Osmotolerant and facultative anaerobe - causes pimples, boils, etc.
255
Clostridium perfringens
Strict (obligate) anaerobe - causes gangrene
256
Neisseria gonorrhoeae
G-, Microaerophile - causes gonorrhea
257
Listeria monocytogenes
Psychrotroph - causes listeriosis
258
Bacillus stearothermophilus
G+, Thermophile and used in Kilit ampule
259
Bacillus
Most UV resistant when endospores are formed
260
Escherichia coli
G-, Mesophile and metallic green on Endo agar - causes UTI and sepsis
261
Klebsiella pneumoniae
Red on Endo agar
262
Salmonella typhi
Clear/light pink on Endo agar - causes typhoid fever
