MYCOBACTERIA Flashcards

1
Q

Most familiar species of Mycobacteria

A
  • Mycobacterium tuberculosis (MTB)
  • Mycobacterium leprae
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2
Q

Slender, slightly curved or straight, rod-shaped organisms

A

Mycobacteria

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3
Q

Mycobacteria: Motile or Nonmotile

A

Nonmotile

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4
Q

Mycobacteria: gram stain

A

Gram positive

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5
Q

Pathogenic mycobacteria grow more _____________ than most other bacteria pathogenic for humans

A

slowly

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6
Q

_____________ weeks of incubation on complex media atspecific optimal temperatures

A

2-6

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7
Q

_______________ – fails to grow in vitro (causative agent of
leprosy); produce chronic infection

A

Mycobacterium leprae

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8
Q

_______________ – fails to grow in vitro (causative agent of
leprosy); produce chronic infection

A

Mycobacterium leprae

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9
Q

causative agent of leprosy

A

Mycobacterium leprae

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10
Q

Mycobacterium leprae fails to grow in ___________

A

vitro

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11
Q

Rapidly growing species generally grow on ____________ media in 2 to 3 days at temperatures of 20° to 40° C

A

simple

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12
Q

Rapidly growing species generally grow on simple media in ________ days at temperatures of 20° to 40° C

A

2 to 3

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13
Q

Rapidly growing species generally grow on simple media in 2 to 3 days at temperatures of ___________

A

20° to 40° C

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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

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15
Q

Laboratory Safety Considerations for Ventilation

A

negative air pressure (separate)

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16
Q

Biological safety cabinet

A

Class I negative pressure cabinet or Class II vertical, laminar flow cabinets

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17
Q

Minimum level of respiratory protection

A

N-95 Mask

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18
Q

Respirator that contains a National Institute for Occupational Safety and Health–certified N series filter with a ___% efficiency rating

A

95%

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19
Q

Use of Proper Disinfectants:

3-8% formaldehyde or 2% glutaraldehyde –
contact time: __________

A

at least 30 minutes

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20
Q

Use of Proper Disinfectants:

_______% formaldehyde or _______% glutaraldehyde –
contact time: at least 30 minutes

A

0.1-0.5% sodium hypochlorite – contact time:
10-30 minutes

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21
Q

Use of Proper Disinfectants:

Phenol-soap mixtures containing _____________ or
other ____________ derivatives – contact time: 10-30
minutes

A

orthophenol; phenolic

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22
Q

Phenol-soap mixtures containing orthophenol or
other phenolic derivatives – contact time:__________
minutes

A

10-30 mins

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23
Q

Use of Proper Disinfectants:

5% phenol – contact time: _______________

A

10-30 minutes

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24
Q

_______ % phenol – contact time: 10-30 minutes

A

5%

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25
Q

Use of Proper Disinfectants:

__________% sodium hypochlorite – contact time:
10-30 minutes

A

0.1-0.5%

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26
Q

Use of Proper Disinfectants:

0.1-0.5% sodium hypochlorite – contact time:
__________ minutes

A

10-30 minutes

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27
Q

Most common specimen: _________ and ________

A

sputum and bronchial aspirates

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28
Q

Respiratory specimens, ___________ specimen should be
collected on three consecutive days

A

early-morning

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29
Q

Early-morning specimen should be collected on ______________

A

three consecutive days

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30
Q

Volume of sputum: _____ mL

A

5-10 mL

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31
Q

Delay in processing: ______________________

A

refrigerate overnight

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32
Q

collected when sputum is not obtainable

A
  • Bronchial washing
  • bronchoalveolar lavage (BAL)
  • transbronchial biopsy
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33
Q

If at least two of the first three sputum direct smears are positive – _____________

A

confirm a diagnosis

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34
Q

Acceptable Specimens for processing

Respiratory Specimen

A
  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
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35
Q

Acceptable Specimens for processing

Body Fluids

A
  1. pleural fluid
  2. pericardial fluid
  3. joint aspirate
  4. gastric aspirate
  5. peritoneal fluid
  6. cerebrospinal fluid
  7. stool
  8. urine
  9. pus
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36
Q

Acceptable Specimens for processing

Body tissues

A
  1. blood
  2. bone marrow biopsy / aspirate
  3. solid organ
  4. lymph node
  5. bone
  6. skin
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37
Q

Digestion and Decontamination of Specimens

Purpose:
(1) to liquefy the sample through _________________ of the
proteinaceous material

A

digestion

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38
Q

Digestion and Decontamination of Specimens

Purpose:
(1) to liquefy the sample through digestion of the
______________

A

proteinaceous material;

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39
Q

Digestion and Decontamination of Specimens

Purpose:
to allow the_______________ to
contact and kill the nonmycobacterial organisms

A

chemical decontaminating agent

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40
Q

Digestion and Decontamination of Specimens

Purpose:
(2) to allow the chemical decontaminating agent to
contact and kill the ______________ organisms

A

nonmycobacterial

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41
Q

Decontamination and digestion agents: most popular

A

4-2% Sodium hydroxide (most popular) –
serve as DC and DG agent

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42
Q

Decontamination and digestion agents:

_____________ – mucolytic agent (DG)
- Muco-purulent specimens allows the
sodium hydroxide to penetrate

A

N-Acetyl-L-Cysteine

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43
Q

Decontamination and digestion agents:

N-Acetyl-L-Cysteine – ___________
- Muco-purulent specimens allows the
sodium hydroxide to penetrate

A

mucolytic agent (DG)

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44
Q

Decontamination and digestion agents:

N-Acetyl-L-Cysteine – mucolytic agent (DG)
- Muco-purulent specimens allows the
______________ to penetrate

A

sodium hydroxide

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45
Q

Decontamination and digestion agents:

______________– aka sputolysin; same with NALC
(DG)

A

Dithiothreitol

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46
Q

Decontamination and digestion agents:

Dithiothreitol – aka ___________; same with NALC
(DG)

A

sputolysin

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47
Q

Decontamination and digestion agents:

___________________ (Zephiran) - DC

A

Benzalkonium chloride

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48
Q

Decontamination and digestion agents:

Benzalkonium chloride (____________) - DC

A

Zephiran

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49
Q

Decontamination and digestion agents:

_____________ – decontaminate specimens contaminated with Pseudomonas aeruginosa; cystic fibrosis

A

5% Oxalic acid

50
Q

Decontamination and digestion agents:

5% Oxalic acid – decontaminate specimens contaminated with _________________; cystic fibrosis

A

Pseudomonas aeruginosa

51
Q

Decontamination and digestion agents:

5% Oxalic acid – decontaminate specimens contaminated with Pseudomonas aeruginosa; ________________

A

cystic fibrosis

52
Q

AFB Staining
 Bacterial smear: __________________
 Primary stain – _____________
 Decolorizing agent – ____________
 Counterstain – ____________
 Acid-fast organisms: _______ against a blue background
 Nonacid-fast organisms: (what color)

A

AFB Staining
 Bacterial smear: 2 cm long and 1 cm wide ; painlty
 Primary stain – carbolfuchsin
 Decolorizing agent – acid-alcohol
 Counterstain – methylene blue
 Acid-fast organisms: Red against a blue background
 Nonacid-fast organisms: Blue

53
Q

____________________ Procedure – application of heat (mordant) with carbolfuchsin stain (primary stain), acid alcohol (decolorizing agent), and methylene blue (counterstain; more consistent results

A

Ziehl-Neelsen Procedure

54
Q

Ziehl-Neelsen Procedure – application of ___________ (mordant) with carbolfuchsin stain (primary stain), acid alcohol (decolorizing agent), and methylene blue (counterstain; more consistent results

A

heat

55
Q

Ziehl-Neelsen Procedure – application of heat (mordant) with ___________ (primary stain), acid alcohol (decolorizing agent), and methylene blue (counterstain; more consistent results

A

carbolfuchsin stain

56
Q

Ziehl-Neelsen Procedure – application of heat (mordant) with carbolfuchsin stain (primary stain), ________________ (decolorizing agent), and methylene blue (counterstain; more consistent results

A

acid alcohol

57
Q

Ziehl-Neelsen Procedure – application of heat (mordant) with carbolfuchsin stain (primary stain), acid alcohol (decolorizing agent), and ________________ (counterstain; more consistent results

A

methylene blue

58
Q

____________ Stain – cold stain; tergitol is used as a mordant
- Oil immersion
- Minimum of 300 fields

A

Kinyoun Stain

59
Q

Kinyoun Stain – cold stain; ___________is used as a mordant
- Oil immersion
- Minimum of 300 fields

A

tergitol

60
Q

Kinyoun Stain – cold stain; tergitol is used as a mordant
- Oil immersion
- Minimum of __________ fields

A

300 fields

61
Q

Kinyoun Stain – (hot or cold) stain; tergitol is used as a mordant
- Oil immersion
- Minimum of 300 fields

A

cold

62
Q

More sensitive than carbolfuchsin stains; about 18 % are negative and negative on two stains

A

Auramine or Auramine-rhodamine Fluorochrome
stains

63
Q

Auramine or Auramine-rhodamine Fluorochrome
stains: positive result

A

bright, yellow-orange bacilli against a dark background

64
Q

Partially acid-fast organisms:

A
  • Nocardia spp.
  • Legionella micdadei
  • Rhodococcus spp
65
Q

Culture Media and Isolation Methods
- ________% CO2
- pH between 6.5 and 6.8

A

5-10%

66
Q

Culture Media and Isolation Methods
- 5-10% CO2
- pH between ________

A

6.5 and 6.8

67
Q

Recommended for routine culturing of specimens
for the recovery of AFB

A

Solid based media (LJ media) + Liquid based media (routine culture of specimen)

68
Q

Egg-based media (3)

A
  1. LJ media
  2. Petragnani media
  3. American Thoracic Society (ATS) media
69
Q

most commonly culture media used in in clinical laboratories

A

Lowenstein-Jensen (LJ) Medium

70
Q

contains malachite green – inhibit gram-positive bacteria

A

egg-based media

71
Q

Selective media that contain antimicrobial
agents

A
  1. Gruft modification of LJ
  2. Mycobactosel (Becton Dickinson Diagnostic Systems - mixed with nonselected media
72
Q

Serum albumin agar media

A
  • Middlebrook 7H10
  • Middlebrook 7H11 agar
73
Q

agar media that contains 0.1% casein hydrolysate

A

Middlebrook 7H11 agar

74
Q

agar media that improves the recovery of isoniazid-resistant strains of M. tuberculosis

A

Middlebrook 7H11 agar

75
Q

Liquid media (2)

A
  • Middlebrook 7H9 broth
  • Dubos Tween Albumin
76
Q

In general, they appear as having a smooth and soft or rough and friable appearance

A

Mycobacteria

77
Q

rough often exhibit a prominent patterned texture referred to as cording (curved strands of bacilli)

A

Mycobacterium tuberculosis

78
Q

variable appearance with glossy whitish colonies often occurring with smaller translucent colonies

A

Mycobacterium avium complex

79
Q

Growth Rate

produce colonies in fewer than 7 days on
solid media

A

Rapid Growers

80
Q

Growth Rate

more than 7 days of solid media

A

Slow Growers

81
Q

3 Mycobacterium spp. that grow best at 30°C to 32°C

A

1. Mycobacterium marinum
2. Mycobacterium ulcerans
3. Mycobacterium haemophilum

82
Q

Mycobacterium sp. that grows best at at 42°C

A

Mycobacterium xenopi

83
Q

Photoreactivity

produce carotene pigment on exposure to light

A

Photochromogens

84
Q

Photoreactivity

Color ranges from pale yellow to orange

A

Photochromogens

85
Q

Photoreactivity

produce pigment in the light or dark

A

Scotochromogens

86
Q

Photoreactivity

buff (tan) colonies; nonphotoreactive

A

Nonchromogenic or nonphotochromogenic

87
Q

Photoreactivity

Exposure to light does not induce pigment formation

A

Nonchromogenic or nonphotochromogenic

88
Q

Example of nonphotochromogenic bacteria

A

M. tuberculosis

89
Q

Is detected by measuring nicotinic acid, which reacts with cyanogen bromide in the presence of aniline to form a yellow compound

A

Niacin Accumulation

90
Q

Recommended to be done on egg agar cultures (3-4 weeks old)

A

Niacin Accumulation

91
Q

Niacin Accumulation Results
Positive: ____________
Negative: ________________

A

Niacin Accumulation Results
Positive: M. tuberculosis (yellow)
Negative: Other Mycobacterium spp. (colorless)

92
Q

Nitrate Reduction
Positive: for which bacteria

A

Nitrate Reduction Positive for:
1. M. kansasii
2. M. szulgai
3. M. fortuitum
4. M. tuberculosis

93
Q

Nitrate Reduction

A positive test is a ______ pigment

A

red pigment

94
Q

Is performed as with the method used for Enterobacteriaceae

A

Nitrate Reduction

95
Q

All Mycobacteria spp. are catalase ___________ (not all strains)

A

catalase - positive

96
Q

Catalase Test

  • Reagent: ______________
  • Medium: _________
A
  • Reagent: 30% hydrogen peroxide
  • Medium: Tween 80
97
Q

_____________________ 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;

A

Semiquantitative catalase production

98
Q

Semiquantitative catalase production:
reaction reads within ________ minutes

A

5 mins

99
Q

Catalase Test

  • Positive (M. tuberculosis): ________
  • Negative: _________
A
  • Positive (M. tuberculosis): > 45 mm
  • Negative: < 45 mm
100
Q

_________________ is determined by heating the specimen to 68◦C for 20 minutes prior to the addition of hydrogen peroxide

A

Catalase heat stability

101
Q

Catalase heat stability is determined by heating the specimen to ____◦C for ____minutes prior to the addition of hydrogen peroxide

A

68◦C for 20 minutes

102
Q

Catalase heat stability is determined by heating the specimen to 68◦C for 20 minutes prior to the addition of ________________

A

hydrogen peroxide

103
Q

Test to distinguish scotochromogenic and nonphotochromogenic bacteria

A

Hydrolysis of Tween 80

104
Q

Hydrolysis of Tween 80 is a Test to distinguish ______________and
______________ bacteria

A

scotochromogenic ; nonphotochromogenic

105
Q

Hydrolysis of Tween 80

Detecting the ability of Mycobacteria to split the detergent Tween 80 into ________________ and ________________________ by the presence of enzyme lipase

A

oleic acid and polyoxyethylated sorbitol

106
Q

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 ____________

A

enzyme lipase

107
Q

Hydrolysis of Tween 80

  • Medium used: ____________________
  • pH indicator: _______________
  • Positive reaction: ____________
A
  • Medium used: Tween 80 (acidic)
  • pH indicator: Neutral red (amber color)
  • Positive reaction: pink color (M. tuberculosis)
108
Q

Tellurite Reduction

Reduction of colorless potassium tellurite to _______________ in 3 to 4 days is a characteristic of MAC (M. avium)

A

black metallic tellurium

109
Q

Tellurite Reduction

Reduction of colorless potassium tellurite to black metallic tellurium in ________________ days is a characteristic of MAC (M. avium)

A

3 to 4 days

110
Q

Mycobacterium tuberculosis other names

A

Koch Bacillus and Human Tubercle Bacilli

111
Q

Mycobacterium tuberculosis other names

A

Koch Bacillus and Human Tubercle Bacilli

112
Q

Mycobacterium tuberculosis first described by ____________ in __________

A

Robert Koch; 1882

113
Q

Causative agent of tuberculosis (TB)

A

Mycobacterium tuberculosis

114
Q

Mode of transmission of Mycobacterium tuberculosis

A

Airborne droplets

115
Q

It is one of the oldest documented communicable diseases

A

Mycobacterium tuberculosis

116
Q

Mycobacterium tuberculosis:
3 Types of Infection or Exposure

A

Types of Infection or Exposure:
 Primary Tuberculosis
 Secondary or Reactivation Tuberculosis
 Extrapulmonary Tuberculosis

117
Q

It is the initial infection of MTB

A

Primary Tuberculosis (Primary exposure)

118
Q

Primary Tuberculosis (also means ____________)

A

(Primary exposure)

119
Q

The mycobacterium is eradicated by the host cellular immune response or walled off in a granuloma in the lung

A

Primary Tuberculosis (Primary exposure)

120
Q

Reactivation of latent infections can occur in
________________individuals and cause ______________ tuberculosis; never been treated for TB

A

immunocompromised ; secondary

121
Q

Positive PPD (Purified protein derivative) skin test

A

Primary Tuberculosis (Primary exposure)