Lab Practical Flashcards
(175 cards)
1
Q
Week 2
A
Aseptic Tech and, Microscopes, microbes
2
Q
liquid or solid – provide nutrient
Prepare by mixing all chemicals, then sterilized (autoclaved or in some cases, filtered)
A
Medium
3
Q
should contain 1 species of microbes
A
Pure culture
4
Q
Aseptic techniques
A
- Minimize contamination
- Place tubes in test tubes racks
- Do not hold tubes by its cap
- Hold loop like a pencil
- Adjust Bunsen Burner
5
Q
light transmitted through the specimen
A
Bright-field microscope
6
Q
Light passes through the
A
condenser lens
7
Q
bending) of light as it passes through the objective lens
magnifies the image
A
refraction
8
Q
magnifies the image again and produce a virtual image
A
ocular lens
9
Q
Total magnification is calculated how
A
Total mag. = mag. from objective lens x mag. from ocular lens
10
Q
is the minimum distance between 2 points so that
they can be seen as 2 separate point
A
Resolution
11
Q
Week 3
A
Streak Plate, Spread Plate, Differential, Selective Media
12
Q
Start with a mixed culture of microbes and decrease the cell density during
streaking
A
streak plate
13
Q
Individual bacteria will be separated from the sample and grow into
A
Colony Forming Unit = CFU
14
Q
- A common isolation technique (starting with a low concentration of
microbes) - To form a lawn of microbes (starting with a high concentration of microbes)
A
SPREAD PLATE
15
Q
designed to enhance the isolation procedure by inhibiting growth of some organisms while encouraging the growth of others
A
selective media
16
Q
can a media be both selective and differential
A
yes
17
Q
contain indicators to expose differences between organisms, which also make them
A
differential media
18
Q
it encourages growth of some organisms and discourages (inhibits) growth of other
A
selective
19
Q
it allows us to distinguish between different microbes
A
differential
20
Q
each of its ingredients is known and in exactly what amounts.
A
defined, or “chemically defined,”
21
Q
it contains one or more ingredient(s) of unknown composition and/or amount
A
undefined or “complex,”
22
Q
make the medium selective
A
inhibititors
23
Q
are almost always what make the medium differential
A
Substrates
24
Q
make a desired or expected reaction visible
A
Indicators
25
Indicators are present in what kind of media
differential
26
is a dye that changes color as pH changes
indicator
27
differentiate and sometimes identify microorganisms based on specific biochemical characteristics
differential tests or biochemical tests
28
Week 4
Gram staining and Motility
29
is the single most important differential stain in bacteriology
Gram stain
30
what kind of test is Gram staining
differential
31
steps for gram-staining
crystal violet
Gram idodine
decolorization (acetone)
safranin
32
is a semisolid medium designed to detect bacterial motility.
motility test
33
is motility test defined or undefined
undefined or complex medium
34
what is the indicator for the motility test
TTC
35
what kind of test is motility test
differential
36
Week 5
MSA, MacConkey, Starch Hydrolysis, Standard Plate Count
37
is Mannitol Salt Agar (MSA) defined or undefined
defined medium
38
what is Mannitol Salt Agar (MSA) made of
beef extract, peptone, mannitol, sodium chloride, phenol red, and agar
7.5% sodium chloride
39
what kind of test is Mannitol Salt Agar (MSA)
Selective medium and differencial
40
what is Mannitol Salt Agar (MSA) testing for
select against most bacteria other than Staphylococcus
41
what is the pH indicator for Mannitol Salt Agar (MSA)
Phenol red
42
pH indicator scale for Mannitol Salt Agar (MSA)
Yellow at pH < 6.8
Red at pH: 7.4-8.4
Pink at pH > 8.4
43
what does Mannitol Salt Agar (MSA) use for fermentation
Mannitol
44
what makes Mannitol Salt Agar (MSA) differential
Mannitol
45
what makes Mannitol Salt Agar (MSA) selective
NaCl
46
does Mannitol Salt Agar (MSA) need to have a control on Nutrient Agar
yes
47
what does poor growth on a Mannitol Salt Agar (MSA) plate mean
organisms is inhibited by NaCl
not Staphylococcus
48
what does good growth on a Mannitol Salt Agar (MSA) plate
organisms is not inhibited by NaCl
it is Staphylococcus
49
what does yellow growth on a Mannitol Salt Agar (MSA) plate
organism produces acid from mannitol fermentation
Staph aureus
50
what does red growth on a Mannitol Salt Agar (MSA) plate
organism does not ferment mannitol
Staphylococcus
51
is macconkey agar defined or undefined
undefined medium
52
what kind of medium is MacConkey agar
selective and differential medium
53
what is MacConkey agar selective for
Gram negative
54
what does MacConkey agar differentiate
Enterobacteriaceae based on ability to ferment lactose
55
what is MacConkey agar pH indicator
Neutral red
56
what makes MacConkey agar selective
crystal violet and bile salts
57
what makes MacConkey agar differential
whether or not produces acid from lactose fermentation
58
what does Poor growth (P) or no growth (N) mean for MacConkey agar differential
Organism is inhibited by crystal violet and/or bile
Gram positive
59
what does good growth mean for MacConkey agar differential
Organism is not inhibited by crystal violet or bile
Gram negative
60
what does Pink to red growth with or without bile precipitate (R) mean for MacConkey agar differential
Organism produces acid from lactose fermentation
Probable coliform
[Enterobacteriaceae]
61
what does Growth is "colorless" (not red or pink) (C) mean for MacConkey agar differential
Organism does not ferment lactose.
Noncoliform
62
does MacConkey agar need a control NA
yes
63
is starch hydrolysis (amylase test) defined or undefined
defined
64
what ingredients are in starch hydrolysis (amylase test)
starch agar, iodine solution, and bacterial cultures
65
what kind of test is starch hydrolysis (amylase test)
differential test
66
what is starch hydrolysis (amylase test) differential for
differentiates between bacteria that can and cannot produce the enzyme amylase, which breaks down starch
67
what is added to starch hydrolysis (amylase test) to see the result
iodine
68
is used to detect the presence or absence of starch in the vicinity around the bacterial growth
the reagent iodine
69
week 6
Phenol Red and PHENYLETHYL ALCOHOL AGAR [Pea]
70
what type of medium is phenol red broth
differential medium
71
Phenol red broth is considered an undefined or defined medium
undefined or complex medium
72
ingredients of Phenol red broth
peptone and meat extract
73
pH indicator for Phenol red broth
phenol red
74
pH indicator scale for Phenol red broth
* Yellow below pH 6.8
* Pink above pH 7.4
75
sugars used for Phenol red broth
- Lactose
- Sucrose
- Glucose
76
is added to each tube as an indicator of gas production
inverted Durham tube
77
what does phenol red broth differentiate
used to differentiate members of Enterobacteriaceae and to distinguish them from other Gram-negative rods. It also is used to distinguish between Gram-positive fermenters
78
what does this mean Yellow broth, bubble in tube
Fermentation with acid and gas end products
79
Yellow broth, no bubble in tube
Fermentation with acid end products; no gas produced
80
Red broth, no bubble in tube
No fermentation
81
Pink broth, no bubble in tube
Degradation of peptone; alkaline end products
82
Degradation of peptone; alkaline end products
Pink broth, no bubble in tube
83
why does the phenol red broth needed an uninnoculated broth tube
Using the uninoculated controls for color comparison
84
is Phenylethyl Alcohol Agar (PEA) plate undefined to defined
undefined medium
85
what kind of test is Phenylethyl Alcohol Agar (PEA)
selective medium
86
ingredients of Phenylethyl Alcohol Agar (PEA)
Pancreatic digest of casein (15.0 g)
Papaic digest of soybean meal (5.0 g)
Sodium chloride (5.0 g)
β-Phenylethyl alcohol (2.5 g)
Agar (15.0 g)
Distilled or deionized water
pH 7.1–7.5 at 25°C (1.0 L)
87
does Phenylethyl Alcohol Agar (PEA) need a control nutrient agar
yes
88
what is Phenylethyl Alcohol Agar (PEA) selective to
Staphylococcus, Streptococcus, Enterococcus, or Lactococcus
89
what does Poor growth (P) or no growth (N) in Phenylethyl Alcohol Agar (PEA) mean
Organism is inhibited by phenylethyl alcohol
Probable Gram-negative organism
90
what does Good growth (G) in Phenylethyl Alcohol Agar (PEA) mean
Organism is not inhibited by phenylethyl alcohol
Probable Staphylococcus, Streptococcus, Enterococcus, or Lactococcus
91
Week 7
Catalase and Oxidase
92
converts hydrogen peroxide into water and gaseous oxygen
Catalase
93
what kind of test is catalase test
differential test
94
what does Bubbles in a catalase test mean
Catalase is present
+
95
what does no Bubbles in a catalase test mean
Catalase is absent
–
96
what used in catalase test to see result
hydrogen peroxide
97
determines if cells have cytochrome c oxidase
Oxidase test
98
what kind of test is Oxidase test
differential test
99
are chemicals that develop color as they become oxidized
chromogenic reducing agent
100
agent used in Oxidase test
hromogenic reducing agent called tetramethyl-p-phenylenediamine
101
in what time frame should you read a Oxidase test
20 seconds
102
is oxidase test defined or undefined medium
defined
103
what does Dark blue/purple within 20 seconds in oxidase test mean
Cytochrome c oxidase is present
+
104
No color change to blue/purple within 20 seconds
Cytochrome c oxidase is not present
-
105
Week 8
Midterms
106
Week 9
KLIGLER IRON AGAR, GELATINASE AND UREASE
107
what kind of test is Gelatinase Test
differential
108
does Gelatinase Test need a control?
yes
109
what is the solidifying agent for Gelatinase Test
Gelatin
110
what is the gelatinase test made out of
Beef extract
3.0 g
Peptone
5.0 g
Gelatin
120.0 g
Distilled or deionized water
pH 6.6–7.0 at 25°C
1.0 L
111
what does this mean Gelatin is liquid (control is solid)
Gelatinase is present
+
112
what does this mean Gelatin is solid
No gelatinase is present
–
113
what kind of test is Urease Test
differential
114
is Urease Test defined or undefined medium
defined
115
indicator of Urease Test
Phenol red
116
ingredients of Urease Test
east extract
0.1 g
Potassium phosphate, monobasic
9.1 g
Potassium phosphate, dibasic
9.5 g
Urea
20.0 g
Phenol red
0.01 g
Distilled or deionized water
pH 6.8 at 25°C
1.0 L
117
what does a pink urease test mean
Rapid urea hydrolysis; strong urease production
+
118
what does a orange or yellow urease test mean
No urea hydrolysis; organism does not produce urease or cannot live in broth
–
119
is kligler iron agar test defined or undefined medium
defined
120
what kind of test is kligler iron agar test
differential
121
ingredients in kligler iron agar test
- Glucose (0.1 %)
- Lactose (1%)
- Sucrose (1%)
- Sodium thiosulfate
- Ferrous sulfate
122
is reduced
- !!!! under acidic conditions only
Sodium thiosulfate
123
with H2S to form a black precipitate
Ferrous sulfate
124
what does yellow butt yellow slant mean
glucose and lactose fermentation
125
what does yellow butt red slant mean
only glucose fermenatation
126
what does red butt red slant mean
no fermentation
127
what does black butt red slant mean
glucose only fermentation
128
Week 10
Citrate, EMB, DNase
129
what kind of test is Citrate Utilization Test
differential
130
is citrate utilization test defined or undefined
defined
131
ingredients of citrate utilization test
Simmons Citrate Agar
Ingredients
Amount
Ammonium dihydrogen phosphate
1.0 g
Dipotassium phosphate
1.0 g
Sodium chloride
5.0 g
Sodium citrate
2.0 g
Magnesium sulfate
0.2 g
Agar
15.0 g
Bromothymol blue
0.08 g
Distilled or deionized water
pH 6.7–7.1 at 25°C
1.0 L
132
what does citrate utilization test differentiate for
members of the Enterobacteriaceae family
133
is an intermediate of the Krebs (=citric acid) cycle
Citrate
134
does Citrate utilization test need a uninoculated control
yes
135
pH indicator of Citrate utilization test
bromothymol blue
136
Blue (even a small amount) on Citrate utilization test
Citrate is utilized
+
137
No color change; growth on Citrate utilization test
Citrate is utilized
+
138
No color change; no growth on Citrate utilization test
Citrate is not utilized
–
139
Citrate utilization test pH scale
Blue at pH ≥ 7.6
140
what kind of test is
Eosin Methylene Blue Agar
differential and selective
141
is Eosin Methylene Blue Agar defined or undefined
undefined complex
142
does Eosin Methylene Blue Agar need a control NA
yes
143
ingredients of Eosin Methylene Blue Agar
gelatin, lactose, and the dyes eosin Y and methylene blue
144
what is Eosin Methylene Blue Agar selective for
Gram-negative bacteria
145
what is Eosin Methylene Blue Agar differential for
coliforms
146
pH indicator of Eosin Methylene Blue Agar
Eosin Y and Methylene Blue
147
Poor growth (P) or no growth (N) on Eosin Methylene Blue Agar
Organism is inhibited by eosin and/or methylene blue
Gram positive
148
Good growth (G) on Eosin Methylene Blue Agar
Organism is not inhibited by eosin and methylene blue
Gram negative
149
Growth is pink and mucoid (Pi) on Eosin Methylene Blue Agar
Organism ferments lactose with little add production
Possible coliform
150
Growth is "dark" (purple to black, with or without green metallic sheen) (D) on Eosin Methylene Blue Agar
Organism ferments lactose and/or sucrose with acid production
Probable coliform
151
Growth is "colorless" (not red or pink) (C) on Eosin Methylene Blue Agar
Organism does not ferment lactose.
Noncoliform
152
what kind of test is DNA Hydrolysis (DNase Test)
differential test
153
is dna hydrolysis (dnase test) defined or undefined
defined
154
what is dna hydrolysis (dnase test) made of
Tryptose
20.0 g
Deoxyribonucleic acid
2.0 g
Sodium chloride
5.0 g
Agar
15.0 g
Methyl green
0.05 g
Distilled or deionized water
pH 7.1–7.4 at 25°C
1.0 L
155
what is dna hydrolysis (dnase test) differential for
to identify bacteria based on their ability to produce the enzyme DNase
156
dna hydrolysis (dnase test) indicator
methyl green dye
157
what does Clearing in agar (loss of green color around growth) mean in a dna hydrolysis (dnase test)
DNase is present
+
158
what does No clearing in agar around growth mean in a dna hydrolysis (dnase test)
DNase is not present
–
159
Week 11
ANTIMICROBIAL SUSCEPTIBILITY
and
HEKTOEN ENTERIC AGAR
160
what kind of test is Hektoen Enteric Agar
selective and differential
161
is Hektoen Enteric Agar undefined or defined medium
complex (chemically undefined
162
what is Hektoen Enteric Agar differential for
Salmonella and Shigella
163
does Hektoen Enteric Agar need a control NA
yes
164
what is Hektoen Enteric Agar selective for
gram negative
165
indicators of Hektoen Enteric Agar selective
Bile salts
166
ph indicators of Hektoen Enteric Agar selective
Bromothymol blue and acid fuchsin
167
Reacts with H2S produced by bacteria to form a black precipitate
Ferric ammonium citrate (oxidized iron)
168
Poor growth (P) or no growth (N) mean in Hektoen Enteric Agar
Organism is inhibited by bile and/or one of the dyes included
Gram positive
169
Good growth (G) mean in Hektoen Enteric Agar
Organism is not inhibited by bile or any of the dyes included
Gram negative
170
Pink to orange growth (Pi) mean in Hektoen Enteric Agar
Organism produces acid from lactose, sucrose, and or salicin fermentation
Not Shigella or Salmonella
171
Blue-green growth with black precipitate (Bppt) mean in Hektoen Enteric Agar
Organism does not ferment lactose, sucrose, or salicin, but reduces sulfur to hydrogen sulfide (H2S).
Probable Salmonella
172
Blue-green growth without black precipitate (B) mean in Hektoen Enteric Agar
Organism does not ferment lactose, sucrose, or salicin, or reduce sulfur.
Probable Shigella or rarely Salmonella
173
is used to measure the effectiveness of antimicrobial
chemicals
Antimicrobial Susceptibility Test
174
place where the concentration of the antimicrobic agent is becoming too low to stop bacterial growth ANTIMICROBIAL SUSCEPTIBILITY TEST
Minimum inhibitory concentration
175
what to do after Antimicrobial Susceptibility Test is inoculated
Remove the plates from the incubator (or refrigerator). Hold each plate over the black, nonreflective poster board and examine the plate with reflected light. The edge of a zone is where no growth is visible to the naked eye. Measure the diameter of each zone of inhibition in millimeters
