MICROBIOLOGY Flashcards
(241 cards)
1
Q
Capsule can be used for
A
Serotype by swelling
2
Q
To demonstrate capsule, grow the culture on media containing
A
- milk
* serum
3
Q
The Quellung test depends on the antigenic specificity of the
A
capsule
4
Q
Dark staining granules
A
Metachromatic
5
Q
Organisms that vary in size and shape
A
Pleomorphic
6
Q
In the bacterial growth cycle, growth ceases because nutrients are exhausted or toxic metabolic products have accumulated in the
A
Stationary/Plateau Phase
7
Q
Bacteria form spores
A
- Clostridium
* Bacillus
8
Q
Bacteria that grow in the absence of athmospheric (free) oxygen and obtain oxygen from oxygen containing compounds
A
Anaerobes
9
Q
The temperature at which bacteria grow best
A
Optimum
10
Q
A slimy colony on blood agar medium indicates which of the following characteristics may be present?
A
Organism has a capsule
11
Q
On blood agar plates a small zone of alpha-hemolysis surrounded by zone beta hemolysis after refrigeration
A
Alpha-prime
12
Q
When using fractional sterilization the sequence
A
Heating (kill vegetative bacteria)
Incubation (spores germinate)
Heating (kills remaining vegetative bacteria)
13
Q
Most effective method of sterilization
A
Autoclave
14
Q
Used for quality control for the dry heat oven
A
Bacillus subtilis
15
Q
Filters can give 100% sterility
A
Millipore (0.22um)
16
Q
Media that cannot be heated can be sterilized by
A
Filtration
17
Q
Which of the following is not a disinfectant?
A
70% alcohol
18
Q
Iodophors are composed of
A
Iodine and Detergent
19
Q
Quarternary ammonium disinfectants are easily inactivated by
A
Organic Material
20
Q
Term that describes a process or treatment that renders a medical device, instrument or environment surface to handle
A
Decontamination
21
Q
Gram positive bacteria stain
A
Purple
22
Q
The mordant used in the Ziehl-Neelsen acid fast stain
A
Heat
23
Q
Smear for an acid fast stain fixed
A
Slide warmer at 65C for 2 hours
24
Q
Acid fast bacteria appear what color microscopically
A
Red
25
Acid fast organism in tissue are best stained by
Kinyoun
26
In the Ziehl-Neelsen staining mtd, the decolorizer
Alcohol + HCl
27
An exmaple of negative stain
India Ink stain
28
NOT gram negative
Peptococcus
29
NOT an anaerobe
Campylobacter
30
If a patient is taking antimicrobials, which can neutralize the antimicrobials
Thiol broth
31
From a bronchial washing, organisms are seen on a Gram stain, but no growth occurs aerobically and anaerobically. This most likely due to
Inhibition by antibiotic therapy
32
Use to remove antimicrobials before culturing
Antimicrobial Removal Device
33
Sodium Polyanethol sulfonate may be used as an anticoagulant in blood cultures because it
* Prevents phagocytosis
| * Neutralizes the bactericidal effect of human serum
34
Most abundant normal flora in throat culture
Alpha hemolytic Streptococcus
35
Most common pathogen in throat culture
Group A Streptococcus
36
Why must blood agar plates for throat cultures can be incubated aerobically and anaerobically when beta hemolytic streptococci are suspected
Some may produce beta hemolysis under aerobic conditions
37
Nasopharyngeal swabs are recommended for the detection of carriers such as
Haemophilus influenzae
Neisseria
Bordetella pertussis
38
Todd- Hewitt broth is recommended for
Culture of beta-hemolytic streptococci for fluorescence microscopy
39
Phenylethyl alcohol is used in media to
Inhibit gram negative bacteria
40
Why is a first morning urine specimen preferred for urine cultures
Specimen is more concentrated
41
what indicates vaginal or urethral contamination of urine
Many squamous epithelial cells
42
In the pour-plate mtd for colony counts, how does the amount of agar added affect the dilution
Dilution is not affected
43
Smears of CSF are usually stained with
Gram stain
| India ink stain
44
Smears of CSF are prepared from
CSF sediment
45
Test for bacterial antigen on cultures isolated from CSF is more sensitive and faster
Latex agglutination tests
46
Staphylococcal protein A coated with antiserum is used in which of the serological test on CSF
Coagglutination test
47
NOT cause of venereal disease
Staphylococcus aureus
48
Using sheep blood agar plates eliminates beta hemolytic
Hemophilus
49
A positive tube coagulase test is observed for
clotting of plasma
50
Type of plasma is used for the tube coagulase test
Rabbit
51
Some citrate positive organism cause a false positive tube coagulase test because the organism uses the citrate
and releases Calcium
52
A nonhemolytic, catalase positive, coagulase negative, gram possitive coccus
Staphylococcus epidermidis
53
Preferred mtd of differentiating S.aureus from S. epidermidis
Coagulase test
54
Staphylococci that cause of UTI in young females
S. saphrophyticus
55
S. aureus can be isolated from stool cultures by the use of
Medium with 7.5% salt concentration
56
Most common cause of bacterial food poisoning in the US
Staphylococcus aureus
57
Gram positive cocci that ferment glucose
Staphylococci
58
Produced by beta hemolytic streptococci, is oxygen stable and non antigenic
Streptolysin S
59
Cultures for beta hemolytic streptococci must include
Anaerobic incubation to detect hemolysis in all strains
60
Destroyed by oxygen
Streptolysin O
61
Group A beta hemolytic streptococci
Bacitracin Susceptible
62
Streptococcus pneumoniae
Optochin susceptible
63
Alpha hemolytic streptococci
Optochin resistant
64
Group B, beta hemolytic streptococci
Hippurate hydrolysis positive
| CAMP test positive
65
Enterococcus
Bile esculin positive
66
Whenever a biochemical test is substituted for a serological test is reported
As "presumptive" with the name of the biochemical test
67
CAMP is a factor produced by group B beta-hemolytic streptococci that
Enlarges the zone of lysis formed by staphylococcal beta-hemolysin
68
A positive Quellung test is
From capsular swelling due to an antigen-antibody reaction
69
Serological test used for a confirmatory test for streptococci
Phadebac test
Fluorescent antibody test
Lancefield precipitin test
70
When performing a bacitracin differentiation test for group A beta hemolytic streptococci, use disks that have how many units?
0.02-0.04 units
71
Group A streptococci
"strep throat"
| Scarlet fever
72
Group B streptococci
Major pathogen of the newborn
73
Alpha hemolytic streptococci
Subacute bacteria Endocarditis
74
What do optochin and bacitracin tests have in common
Growth inhibition is a positive result
75
Bile esculin test is used to differentiate
Group D streptococci from other strep
76
Hippurate hydrolysis is used to differentiate
Group A from Group B streptococci
77
A bacitracin resistant, hippurate hydrolysis positive, bile esculin positive, beta hemolytic Streptococcus that grows in 6.5% NaCl
Enterococcus
78
Pneumococci that are resistant to penicillin should be tested for
Production of beta lactamase
79
Gram negative, coffee bean shaped diplococci with adjacent sides flattened
Neisseria
80
Diagnosis of gonorrhea in males can be made from
Positive urethral smear
Symptoms
History
81
Specimens may be appropriate for culturing Neisseria gonorrhea
Eyes
Rectum
Oral cavity
82
Medium choice for culturing gonococci and meningococci
Modified Thayer Martin
83
Differentiates Thayer Martin medium from Modified Thayer Martin medium
Trimethoprim lactate
84
Thayer Martin medium is basically an
Enriched chocolate agar
85
Color of a positive oxidase test
Dark Purple
86
Genera that are oxidase positive
Moraxella
Aeromonas
Neisseria
87
Techniques that can be used when performing the oxidase test
Put a drop of reagent on the colony
Rub colony on a filter paper strip and add a drop of reagent
Rub the colony on a piece of filter paper containing the reagent
88
What do "PPNG" gonococci produce
Penicillinase-producing gonococci
89
Methods for testing for the production of beta lactamase
Chromogenic cephalosphorin mtd
Acidometric mtd
Iodometric mtd
90
Positive reaction for the beta lactamase chromogenic cephalosphorin mtd
Color change
91
An oxidase positive, gram neg coccus from a throat culture
Neissseria
92
A fastidious, oxidase positive, gram negative coccus from rectal swab
Neisseria gonorrhea
93
Neisseria meningitidis degrades what sugars
Glucose
| Maltose
94
Which of the following test can give a presumptive identification of Branhamella catarrhalis if the isolate is a gram neg diplococcus that is oxidase positive and isolated from middle ear fluid
Beta lactamase test
95
Why should beta lactamase tests be performed with growth from primary isolation media
Plasmid coding for the enzyme may be lost in subculturing
96
Purpose of potassium tellurite in tellurite medium
Inhibits the normal flora
97
Potassium tellurite medium produces what color colonies of Corynebacterium diphtheriae
Gray-black
98
When culturing Corynebacterium diphtheriae, which of the following media will enhance pleomorphism and granule production
Leoffler serum agar
| Pai coagulated egg medium
99
Morphology of Corynebacterium diphtheriae
Gram positive, nonmotile rods
100
The term "pallisading" "picket fence" and "chinese letter" describe the common arrangement of cells of
Corynebacterium
101
Babes Ernst granules are characteristics of
Corynebacterium diphtheriae
102
Considered diphtheroids
Corynebacterium xeroxis
| Corynebacterium JK
103
Diphtheroids found in the normal throat
Corynebacterium pseudodiphtheriticum
104
Elek test is for the detection of
Corynebacterium diphtheriae toxin, in vitro
105
The morphological cycle of Rhodococcus equi from coccoid to rod form tales
24 hours
106
Gram positive to gram variable coccobacillus
Listeria monocytogenes
107
Listeria monocytogenes produces a positive of what biochemical test
Catalase
108
Virulence test for Listeria monocytogenes
Anton test
109
Refrigeration of the specimen for several months may enhance isolation of
Listeria monocytogenes
110
Differentiate Listeria monocytogenes from the corynebacteria
Non motile and salicin negative
111
Spore forming cells in bamboo pole arrangement of bacillus anthracis can be found in
Cultures
112
Aerobic, gram positive, sporulating rods can cause food poisoning
Bacillus cereus
113
Very large gram negative rods with spores are seen in a non turbid thioglycollatebroth culture of spinal fluid, but there is no growth anaerobically or aerobically. This most likely due to:
Bacillus sp. in the dehydrated medium are killed and made gram negative by autoclaving the medium
114
Ziehl-Neelsen acid fast staining:
1. Primary dye
2. Mordant
3. Decolorizer
4. Counterstain
1. Carbol fuchsin
2. Heat to speed staining
3. Acid (3% HCl) alcohol
4. dilute methylene blue
115
Color of non acid fast bacilli stain
blue
116
Acid fast bacilli retain the dye
Carbol fuchsin
117
An acid fast stain that does not use heat as a mordant
Kinyoun stain
118
Media is clear so that the colonies of mycobacteria can be examined microscopically
Middlebrook 7H11
119
Color of negative enzymatic hydrolysis of Tween 80 test
Amber
120
Mycobacterial cultures should be incubated
in 5% Carbon Dioxide
121
A slow growing, unbranched, acid fast rod that is nitrate reduction negative and niacin negative
Mycobacterium bovis
122
Mycobacterium tuberculosis is best differentiated form M. bovis by
Niacin and nitrate reduction test
123
Slow growers
M. kasasii
MAI
M. tb
124
Differential test for identifying the species of Mycobacterium splits phenolphthalein form tripotassium phenolphthalein sulfate within 2-3 days
Arylsulfatase test
125
Used for identification of mycobacteria
Growth rate
Pigment production
Biochemical reactions
126
One tube of Lowenstein-Jensen medium is incubated covered with foil and one tube is incubated uncovered. When is the covered tube observed
When growth appears on the uncovered tube
127
Group IV (rapid growers)
M. fortuitum
M.chelonae
M. phlei
M. smegmatis
128
Macrophages containing acid fast bacilli
Lepra cells
129
Acid fast rods in a specimen from nasal mucosa
Are not a diagnostic point
130
The Fite-Faracco acid fast stain is different from other acid fast stains because it uses
Hematoxylin rather than methylene blue as a counterstain
131
Specimen usually used for the diagnosis of Hansen's disease
Tissue juice
132
Lumpy jaw is caused by
Actinomyces israelli
133
NOT anaerobic
Actinomyces
134
Urease Positive
Nocardia
135
Nocardia will grow on any media that does not contain
Antibiotics
136
Haemophilus influenzae (dis)
Meningitis
137
H. ducreyi (dis)
Ulcerative chancroid
138
H. aegypticus (dis)
Pink eye
139
H. haemolyticus (dis)
Normal flora in respiratory tract
140
Medium preferred for the culture of most Haemophilus
enriched chocolate agar
141
A fastidious, small to filamentous, gram neg rod from nasopharyngeal swab
H. influenzae
142
Cultures of Staphylococcus supplies what for cultures of Haemophilus
V factor
143
Type of blood used in blood agar plates for better production of beta hemolysis of Haemophilus
Horse
144
Organism cause whooping cough
Bordetella pertussis
145
Specie of Bordetella that is urease and oxidase positive
B. parapertussis
146
Preferred medium for the isolation of Bordetella pertussis
Charcoal-cephalexin agar
147
A Brucella isolate that does not produce H2S, does not require CO2 and is not inhibited by thionin or basic fuchsin
Brucella melitensis, biotype 1
148
Gram negative, fastidious bacillus that has been isolated from air conditioning towers
Legionella pneumophila
149
Gram negative, fastidious bacillus that is difficult to stain by Gram stain
Legionella pneumophila
150
A relatively slow growing and fastidious, gram negative rod that produces a characteristic brown pigment on Feeley-Gorman agar
Legionella pneumophila
151
Most sensitive for the diagnosis of infections with Legionella pneumophila
Detection of soluble microbial products in body fluids
152
Best medium for the isolation of Legionella
Buffered charcoal yeast extract agar
153
Composition of Campy gas mixture
10% CO2
5% O2
85% Nitrogen
154
"Rice water" stools often contain
A pure culture of Vibrio cholorae
155
A curved, gram negative rod that is non fermentive, nitrate positive and microaerophilic
Campylobacter jejuni
156
Campylobacter is an
Obligate microaerophile
157
A gram negative, slender, curved rod with a single polar flagellum is the cause of gastroenteritis and best isolated on
Campy blood agar
158
Clue cells may be found in infections with
Gardnerella vaginalis
159
Mycoplasma are not true bacteria because they
Have no cell wall
160
Microorganisms form colonies that are embedded in the agar giving a fried egg appearance
Mycoplasma pneumoniae
161
Best method for the identification of Mycoplasma species
Inhibition of growth by specific antisera
162
Purpose of enrichment fluid media when culturing Enterobacteriaceae
Decreases lag phase of pathogens
| Extends lag phase of normal flora
163
```
Crystal violet
Bile salts
Neutral red
Lactose
Brick red colonies
Colorless colonies
```
MacConkey medium
164
Eosin Y and Methylene bllue
lactose and sucrose
black or purple colonies
colorless colonies
Holt harris EMB medium
165
Eosin Y and Methylene bllue
Lactose only
black or purple colonies
colorless colonies
Levine's EMB agar
166
Non fermenters produce what reaction in triple sugar iron (TSI)
Alkaline slant, alkaline or neutral butt
167
Hydrogen sulfide indicator in Triple Sugar Iron (TSI)
Sodium thiosulfate
168
IMViC is a series of which of the following tests
Indole
Methyl Red
Vogues-Proskauer
Citrate
169
Indicator of methyl red test
Methyl Red
170
Most Enterobacteriaceae give what type of Methyl Red and Voges-Proskauer reactions
Opposite
171
Indicators of Simmons citrate agar
Bromthymol blue
172
```
Lactose only
Bile salts and brilliant green
Neutral red
Citrate to inhibit coliforms and Proteus
Red colonies
Colorless colonies
```
Salmonella- Shigella (SSA)
173
Glucose (dextrose)
Ferrous sulfate
Brilliant Green only; inhibitor for gram positive organisms and coliforms
Black colonies surrounded by black zone with metallic sheen
Green colonies
Bismuth-sulfite (BSA)
174
Phenol Red
Ferric (ammonium) citrate + sodium thiosulfate
xylose, lactose, sucrose
Red colonies with black center
Xylose-Lysine deoxycholate (XLD)
175
Lactose, Sucrose, Salicin
Bromthymol blue
Blue-green colonies with black center
orange salmon pink colonies
Hektoen Enteric Agar (HEA)
176
Whitish snowflake colony surrounded by brilliant red agar
Brillian Green Agar
177
Amino acids that are used in the test for decarboxylase
Lysine
Ornithine
Arginine
178
Why the testing 3 amino acids would require 4 tubes
1 tube is needed for control
179
Enzyme that removes the amino group (NH2) from an amino acid
Deaminase
180
Organisms that produce urease do what to medium
Hydrolyze urea to NH4OH
181
Hydrogen sulfide production, other than in TSI agars requires
An organic source of sulfur
| A source of metal
182
Negative result in the malonate utilization test
Green
| Yellow
183
Gelatinase breaks down gelatin to
Amino acids
184
What indicates a positive DNAse result after 0.1 N HCl is added to plate
Agar clears around the colony
185
The DNAse test is based on
Destruction of sugars in the culture medium
186
If the negative nitrate reduction test does not change color after the powdered zinc is added, how it is reported?
Positive
187
Salmonella, Shigella, E.coli and Serratia are all
Members of Enterobacteriaceae
188
Purpose of the ONPG test
Detects slows lactose fermenters
189
```
From urine culture:
Gram negative rod
TSI= A/A +G
IMViC= ++--
Urease= negative
```
Escherichia coli
190
```
From Blood Culture:
Gram Neg Rod
TSI= A/A +G
IMViC= --++
motile
Lysine decarboxylase= negative
No Capsule
```
Enterobacter cloacae
191
```
From Blood Culture:
Gram Neg Rod
Urease and Phenylalanine deaminase = positive
TSI= K/A +G -H2S
Lysine Decarboxylase= negative
Ornithine Decarboxylase= positive
Motility= positive or negative
```
Morganella morganii
192
```
From Stool Culture:
Gram Neg Rod
Urease and Phenylalanine Deaminase = negative
TSI K/A -G -H2s
Lysine decarboxylase= negative
Non motile
```
Shigella spp.
193
Allows viability of acid production by oxidizers in oxidation-fermentation (OF) medium
Peptone content is low
194
```
From stool culture:
Gram Neg Rod
Urease and Phenylalanine deaminase= negative
TSI= K/A +G +H2S
Motile
Lysine Decarboxylase= positive
Indole= positive
```
Aeromonas hydrophila
195
Oxidase positive
Aeromonas hydrophila
| Moraxella osloensis
196
Reagent used for string test
0.5% sodium desoxycholate
197
Any organism that is indole positive and nitrate reduction positive is also
Cholera red- positive
198
How many tubes of oxidation-fermentation media is/are inoculated and what precautions should be taken?
2 tubes, one covered with oil so air is excluded
199
Normal flora of the skin
Acinetobacter calcoaceticus biotype anitratus
200
PRAS means
Prereduced, anaerobically sterilized
201
Why should thioglycollate broth be boiled for 10 minutes before being used
To drive off oxygen
202
Nagler agar is selective medium for
Clostridium
203
Peptococcus and Peptostreptococcus are both
Anaerobic, Gram Positive Cocci
204
Propionibacteria are
Anaerobic, Gram Positive Rods
205
A gram neg, anaerobic coccus that produces a red fluorescence under ultraviolet light
Veilonella
206
Anaerobic, gram positive rods produce terminal "lollipop" spores
Clostridium tetani
207
Anaerobes causes an antimicrobial associated diarrhea
Clostridium difficile
208
Clostridia produca a double zone of hemolysis around colonies on blood agar
Clostridium perfringens
209
Mycoplasmas pneumoniae is incubated
Aerobically, in a sealed container, in carbon dioxide
210
A positive urease test for ureaplasma is indicated by a
Brown halo surrounding the colonies
211
Organisms produces no haze in a broth culture
Ureaplasma urealyticum
212
Cause Primary Atypical Pneumoniae
Mycoplasma pneumoniae
213
Has both RNA and DNA
Rickettsia
| Chlamydia
214
Rickettsia are transmitted by
Arthropod vectors
215
NOT caused by Rickettsia
Typhoid fever
216
Have a bacterial cell wall
Rickettsia
| Chlamydia
217
Small non motile, coccobacillus that is cultured in yolk sac of a chick embryo
Rickettsia
218
Chlamydia are cultured in
McCoy cells
219
"TRIC" conjunctivitis includes
Inclusion conjuctivitis
| Trachoma
220
Serological test done for Chlamydia trachomatis on genital smears
Direct FA using monoclonal Abs
221
Most common tick-borne disease in the US
Lyme disease
222
What is erythema chronicum migrans (ECM)
Cardinal sign of Lyme disease at site of tick bite
223
What are broad spectrum antibiotics
Act against gram negative bacteria
Act against gram positive bacteria
Acts against bacterial and non bacterial organisms
224
Substances produced by microorganisms, that in very small amounts inhibit other microorganisms are called:
Antibiotics
225
Inhibit the growth of the organism
Bacteriostatic agents
226
The time it takes half a dose of antibiotic to dissappear from the blood is called
Half- life
227
Resistance to an antibiotic can be transferred from a resistant to a susceptible organism
Extrachrosomal plasmid
228
In the Kirby Bauer susceptibility test, the 0.5 McFarland std used to
Adjust the turbidity of the inoculum
229
After inoculating the Mueller-Hinton plates for the Kirby Bauer susceptibility test, how long should the plates dry before adding the disks
3-5 minutes
| Not more than 15 minutes
230
How does one measure the zone of growth inhibitor, for the Kirby-Bauer susceptibility test
On the other side of plate
With the unaided eye
Using a ruler, caliper or template
231
What does the size of the zone of growth inhibition correlate with if the correct procedure has been used
Minimum Inhibitory Concentration
232
If there is too much moisture on the surface of a Mueller-Hinton plate when performing a Kirby Bauer susceptibility test, what will happen to the growth
smaller zone
233
Best indicator of poor storage
Penicillin and Methicillin
234
In Mueller-Hinton agar, what can cause increased resistance of Pseudomonas aeruginosa to aminoglycosides
Increased Calcium and Magnesium
235
When doing a susceptibility test with sulfonamides there are two concentric zones around the disk. How should the zone be measured?
Measure the diameter of the outer zone
236
The lowest concentration of drug that will kill all but the minimum defined proportion of viable organism after incubation for a fixed time under a given set of conditions is definition of the
Minimum lethal concentration
| Minimum bactericidal concentration
237
For quality control when monitoring reagents, how often should reagent DISKS be checked
When container is FIRST opened
| Once each WEEK of use
238
How often should CATALASE, OXIDASE and COAGULASE reagents be tested
When vial is FIRST opened
| Once each DAY of use
239
Record TEMPERATURES of incubators, water baths, heating blocks, refrigeration, freezers and thermometers
At each TIME of use
At the 'beginning' of each DAY
At the 'end' of each DAY
240
Check the face velocity of SAFETY CABINETS each
MONTH
241
Setting of RPMs marked on the face of the rheostat control on the CENTRIFUGE should be checked once
MONTHLY
