MYCOBACTERIA Flashcards
(121 cards)
1
Q
Most familiar species of Mycobacteria
A
- Mycobacterium tuberculosis (MTB)
- Mycobacterium leprae
2
Q
Slender, slightly curved or straight, rod-shaped organisms
A
Mycobacteria
3
Q
Mycobacteria: Motile or Nonmotile
A
Nonmotile
4
Q
Mycobacteria: gram stain
A
Gram positive
5
Q
Pathogenic mycobacteria grow more _____________ than most other bacteria pathogenic for humans
A
slowly
6
Q
_____________ weeks of incubation on complex media atspecific optimal temperatures
A
2-6
7
Q
_______________ β fails to grow in vitro (causative agent of
leprosy); produce chronic infection
A
Mycobacterium leprae
8
Q
_______________ β fails to grow in vitro (causative agent of
leprosy); produce chronic infection
A
Mycobacterium leprae
9
Q
causative agent of leprosy
A
Mycobacterium leprae
10
Q
Mycobacterium leprae fails to grow in ___________
A
vitro
11
Q
Rapidly growing species generally grow on ____________ media in 2 to 3 days at temperatures of 20Β° to 40Β° C
A
simple
12
Q
Rapidly growing species generally grow on simple media in ________ days at temperatures of 20Β° to 40Β° C
A
2 to 3
13
Q
Rapidly growing species generally grow on simple media in 2 to 3 days at temperatures of ___________
A
20Β° to 40Β° C
14
Q
The administration of the microbiology laboratory must ensure that each employee is:
(1) provided with adequate safety equipment,
(2) trained in safe laboratory procedures,
(3) informed of the hazards associated with the procedures,
(4) prepared for action following an unexpected accident, and
(5) monitored regularly by medical personnel
A
Personal safety
15
Q
Laboratory Safety Considerations for Ventilation
A
negative air pressure (separate)
16
Q
Biological safety cabinet
A
Class I negative pressure cabinet or Class II vertical, laminar flow cabinets
17
Q
Minimum level of respiratory protection
A
N-95 Mask
18
Q
Respirator that contains a National Institute for Occupational Safety and Healthβcertified N series filter with a ___% efficiency rating
A
95%
19
Q
Use of Proper Disinfectants:
3-8% formaldehyde or 2% glutaraldehyde β
contact time: __________
A
at least 30 minutes
20
Q
Use of Proper Disinfectants:
_______% formaldehyde or _______% glutaraldehyde β
contact time: at least 30 minutes
A
0.1-0.5% sodium hypochlorite β contact time:
10-30 minutes
21
Q
Use of Proper Disinfectants:
Phenol-soap mixtures containing _____________ or
other ____________ derivatives β contact time: 10-30
minutes
A
orthophenol; phenolic
22
Q
Phenol-soap mixtures containing orthophenol or
other phenolic derivatives β contact time:__________
minutes
A
10-30 mins
23
Q
Use of Proper Disinfectants:
5% phenol β contact time: _______________
A
10-30 minutes
24
Q
_______ % phenol β contact time: 10-30 minutes
A
5%
25
Use of Proper Disinfectants:
__________% sodium hypochlorite β contact time:
10-30 minutes
0.1-0.5%
26
Use of Proper Disinfectants:
0.1-0.5% sodium hypochlorite β contact time:
__________ minutes
10-30 minutes
27
Most common specimen: _________ and ________
sputum and bronchial aspirates
28
Respiratory specimens, ___________ specimen should be
collected on three consecutive days
early-morning
29
Early-morning specimen should be collected on ______________
three consecutive days
30
Volume of sputum: _____ mL
5-10 mL
31
Delay in processing: ______________________
refrigerate overnight
32
collected when sputum is not obtainable
* Bronchial washing
* bronchoalveolar lavage (BAL)
* transbronchial biopsy
33
If at least two of the first three sputum direct smears are positive β _____________
confirm a diagnosis
34
Acceptable Specimens for processing
| Respiratory Specimen
1. Spontaneously expectorated sputum
2. Normal-saline- nebulized, induced sputum
3. Transtracheal aspirate
4. Bronchoalveolar lavage
5. Bronchoalveolar brushing
6. Laryngeal swab
7. Nasopharyngeal swab
35
Acceptable Specimens for processing
| Body Fluids
1. pleural fluid
2. pericardial fluid
3. joint aspirate
4. gastric aspirate
5. peritoneal fluid
6. cerebrospinal fluid
7. stool
8. urine
9. pus
36
Acceptable Specimens for processing
| Body tissues
1. blood
2. bone marrow biopsy / aspirate
3. solid organ
4. lymph node
5. bone
6. skin
37
# Digestion and Decontamination of Specimens
Purpose:
(1) to liquefy the sample through _________________ of the
proteinaceous material
digestion
38
# Digestion and Decontamination of Specimens
Purpose:
(1) to liquefy the sample through digestion of the
______________
proteinaceous material;
39
# Digestion and Decontamination of Specimens
**Purpose**:
to allow the_______________ to
contact and kill the nonmycobacterial organisms
chemical decontaminating agent
40
# Digestion and Decontamination of Specimens
**Purpose:**
(2) to allow the chemical decontaminating agent to
contact and kill the ______________ organisms
nonmycobacterial
41
Decontamination and digestion agents: most popular
4-2% Sodium hydroxide (most popular) β
serve as DC and DG agent
42
Decontamination and digestion agents:
**_____________ β mucolytic agent (DG)**
- Muco-purulent specimens allows the
sodium hydroxide to penetrate
N-Acetyl-L-Cysteine
43
Decontamination and digestion agents:
**N-Acetyl-L-Cysteine β ___________**
- Muco-purulent specimens allows the
sodium hydroxide to penetrate
mucolytic agent (DG)
44
Decontamination and digestion agents:
**N-Acetyl-L-Cysteine β mucolytic agent (DG)**
- Muco-purulent specimens allows the
______________ to penetrate
sodium hydroxide
45
Decontamination and digestion agents:
______________β aka sputolysin; same with NALC
(DG)
Dithiothreitol
46
Decontamination and digestion agents:
Dithiothreitol β aka ___________; same with NALC
(DG)
sputolysin
47
Decontamination and digestion agents:
___________________ (Zephiran) - DC
Benzalkonium chloride
48
Decontamination and digestion agents:
Benzalkonium chloride (____________) - DC
Zephiran
49
Decontamination and digestion agents:
_____________ β decontaminate specimens contaminated with Pseudomonas aeruginosa; cystic fibrosis
5% Oxalic acid
50
Decontamination and digestion agents:
5% Oxalic acid β decontaminate specimens contaminated with _________________; cystic fibrosis
Pseudomonas aeruginosa
51
Decontamination and digestion agents:
5% Oxalic acid β decontaminate specimens contaminated with Pseudomonas aeruginosa; ________________
cystic fibrosis
52
AFB Staining
ο Bacterial smear: __________________
ο Primary stain β _____________
ο Decolorizing agent β ____________
ο Counterstain β ____________
ο Acid-fast organisms: _______ against a blue background
ο Nonacid-fast organisms: (what color)
AFB Staining
ο Bacterial smear: 2 cm long and 1 cm wide ; painlty
ο Primary stain β carbolfuchsin
ο Decolorizing agent β acid-alcohol
ο Counterstain β methylene blue
ο Acid-fast organisms: Red against a blue background
ο Nonacid-fast organisms: Blue
53
____________________ Procedure β application of heat (mordant) with carbolfuchsin stain (primary stain), acid alcohol (decolorizing agent), and methylene blue (counterstain; more consistent results
Ziehl-Neelsen Procedure
54
Ziehl-Neelsen Procedure β application of ___________ (mordant) with carbolfuchsin stain (primary stain), acid alcohol (decolorizing agent), and methylene blue (counterstain; more consistent results
heat
55
Ziehl-Neelsen Procedure β application of heat (mordant) with ___________ (primary stain), acid alcohol (decolorizing agent), and methylene blue (counterstain; more consistent results
carbolfuchsin stain
56
Ziehl-Neelsen Procedure β application of heat (mordant) with carbolfuchsin stain (primary stain), ________________ (decolorizing agent), and methylene blue (counterstain; more consistent results
acid alcohol
57
Ziehl-Neelsen Procedure β application of heat (mordant) with carbolfuchsin stain (primary stain), acid alcohol (decolorizing agent), and ________________ (counterstain; more consistent results
methylene blue
58
____________ Stain β cold stain; tergitol is used as a mordant
- Oil immersion
- Minimum of 300 fields
Kinyoun Stain
59
Kinyoun Stain β cold stain; ___________is used as a mordant
- Oil immersion
- Minimum of 300 fields
tergitol
60
Kinyoun Stain β cold stain; tergitol is used as a mordant
- Oil immersion
- Minimum of __________ fields
300 fields
61
Kinyoun Stain β (hot or cold) stain; tergitol is used as a mordant
- Oil immersion
- Minimum of 300 fields
cold
62
More sensitive than carbolfuchsin stains; about 18 % are negative and negative on two stains
Auramine or Auramine-rhodamine Fluorochrome
stains
63
Auramine or Auramine-rhodamine Fluorochrome
stains: positive result
bright, yellow-orange bacilli against a dark background
64
Partially acid-fast organisms:
- Nocardia spp.
- Legionella micdadei
- Rhodococcus spp
65
Culture Media and Isolation Methods
- ________% CO2
- pH between 6.5 and 6.8
5-10%
66
Culture Media and Isolation Methods
- 5-10% CO2
- pH between ________
6.5 and 6.8
67
Recommended for routine culturing of specimens
for the recovery of AFB
Solid based media (LJ media) + Liquid based media (routine culture of specimen)
68
Egg-based media (3)
1. LJ media
2. Petragnani media
3. American Thoracic Society (ATS) media
69
most commonly culture media used in in clinical laboratories
Lowenstein-Jensen (LJ) Medium
70
contains malachite green β inhibit gram-positive bacteria
egg-based media
71
Selective media that contain antimicrobial
agents
1. Gruft modification of LJ
2. Mycobactosel (Becton Dickinson Diagnostic Systems - mixed with nonselected media
72
Serum albumin agar media
* Middlebrook 7H10
* Middlebrook 7H11 agar
73
agar media that contains 0.1% casein hydrolysate
Middlebrook 7H11 agar
74
agar media that improves the recovery of isoniazid-resistant strains of M. tuberculosis
Middlebrook 7H11 agar
75
Liquid media (2)
* Middlebrook 7H9 broth
* Dubos Tween Albumin
76
In general, they appear as having a smooth and soft or rough and friable appearance
Mycobacteria
77
rough often exhibit a prominent patterned texture referred to as cording (curved strands of bacilli)
Mycobacterium tuberculosis
78
variable appearance with glossy whitish colonies often occurring with smaller translucent colonies
Mycobacterium avium complex
79
# Growth Rate
produce colonies in fewer than 7 days on
solid media
Rapid Growers
80
# Growth Rate
more than 7 days of solid media
Slow Growers
81
3 *Mycobacterium spp*. that grow best at 30Β°C to 32Β°C
*1. Mycobacterium marinum
2. Mycobacterium ulcerans
3. Mycobacterium haemophilum*
82
*Mycobacterium sp.* that grows best at at 42Β°C
*Mycobacterium xenopi*
83
# Photoreactivity
produce carotene pigment on exposure to light
Photochromogens
84
# Photoreactivity
Color ranges from pale yellow to orange
Photochromogens
85
# Photoreactivity
produce pigment in the light or dark
Scotochromogens
86
# Photoreactivity
buff (tan) colonies; nonphotoreactive
Nonchromogenic or nonphotochromogenic
87
# Photoreactivity
Exposure to light does not induce pigment formation
Nonchromogenic or nonphotochromogenic
88
Example of nonphotochromogenic bacteria
M. tuberculosis
89
Is detected by measuring nicotinic acid, which reacts with cyanogen bromide in the presence of aniline to form a yellow compound
Niacin Accumulation
90
Recommended to be done on egg agar cultures (3-4 weeks old)
Niacin Accumulation
91
Niacin Accumulation Results
Positive: ____________
Negative: ________________
Niacin Accumulation Results
Positive: M. tuberculosis (yellow)
Negative: Other Mycobacterium spp. (colorless)
92
Nitrate Reduction
Positive: for which bacteria
Nitrate Reduction Positive for:
1. M. kansasii
2. M. szulgai
3. M. fortuitum
4. M. tuberculosis
93
# Nitrate Reduction
A positive test is a ______ pigment
red pigment
94
Is performed as with the method used for Enterobacteriaceae
Nitrate Reduction
95
All Mycobacteria spp. are catalase ___________ (not all strains)
catalase - positive
96
# Catalase Test
* Reagent: ______________
* Medium: _________
* Reagent: 30% hydrogen peroxide
* Medium: Tween 80
97
_____________________ is determined by measuring the height of the column of bubbles when hydrogen peroxide and Tween 80 are added to a deep with mycobacterial growth;
Semiquantitative catalase production
98
Semiquantitative catalase production:
reaction reads within ________ minutes
5 mins
99
# Catalase Test
* Positive (M. tuberculosis): ________
* Negative: _________
* Positive (M. tuberculosis): > 45 mm
* Negative: < 45 mm
100
_________________ is determined by heating the specimen to 68β¦C for 20 minutes prior to the addition of hydrogen peroxide
Catalase heat stability
101
Catalase heat stability is determined by heating the specimen to ____β¦C for ____minutes prior to the addition of hydrogen peroxide
68β¦C for 20 minutes
102
Catalase heat stability is determined by heating the specimen to 68β¦C for 20 minutes prior to the addition of ________________
hydrogen peroxide
103
Test to distinguish scotochromogenic and nonphotochromogenic bacteria
Hydrolysis of Tween 80
104
Hydrolysis of Tween 80 is a Test to distinguish ______________and
______________ bacteria
scotochromogenic ; nonphotochromogenic
105
# Hydrolysis of Tween 80
Detecting the ability of Mycobacteria to split the detergent Tween 80 into ________________ and ________________________ by the presence of enzyme lipase
oleic acid and polyoxyethylated sorbitol
106
# Hydrolysis of Tween 80
Detecting the ability of Mycobacteria to split the detergent Tween 80 into oleic acid and polyoxyethylated sorbitol by the presence of ____________
enzyme lipase
107
# Hydrolysis of Tween 80
* Medium used: ____________________
* pH indicator: _______________
* Positive reaction: ____________
* Medium used: Tween 80 (acidic)
* pH indicator: Neutral red (amber color)
* Positive reaction: pink color (M. tuberculosis)
108
**Tellurite Reduction**
Reduction of colorless potassium tellurite to _______________ in 3 to 4 days is a characteristic of MAC (M. avium)
black metallic tellurium
109
**Tellurite Reduction**
Reduction of colorless potassium tellurite to black metallic tellurium in ________________ days is a characteristic of MAC (M. avium)
3 to 4 days
110
Mycobacterium tuberculosis other names
Koch Bacillus and Human Tubercle Bacilli
111
Mycobacterium tuberculosis other names
Koch Bacillus and Human Tubercle Bacilli
112
Mycobacterium tuberculosis first described by ____________ in __________
Robert Koch; 1882
113
Causative agent of tuberculosis (TB)
Mycobacterium tuberculosis
114
Mode of transmission of Mycobacterium tuberculosis
Airborne droplets
115
It is one of the oldest documented communicable diseases
Mycobacterium tuberculosis
116
Mycobacterium tuberculosis:
3 Types of Infection or Exposure
Types of Infection or Exposure:
οΌ Primary Tuberculosis
οΌ Secondary or Reactivation Tuberculosis
οΌ Extrapulmonary Tuberculosis
117
It is the initial infection of MTB
Primary Tuberculosis (Primary exposure)
118
Primary Tuberculosis (also means ____________)
(Primary exposure)
119
The mycobacterium is eradicated by the host cellular immune response or walled off in a granuloma in the lung
Primary Tuberculosis (Primary exposure)
120
Reactivation of latent infections can occur in
________________individuals and cause ______________ tuberculosis; never been treated for TB
immunocompromised ; secondary
121
Positive PPD (Purified protein derivative) skin test
Primary Tuberculosis (Primary exposure)
