MYCOBACTERIA Flashcards

1
Q

the most familiar species of mycobacteria that is the causative agent of tuberculosis (TB) and Hansen disease (leprosy), respectively.

A

mycobacterium tuberculosis and mycobacterium leprae

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2
Q

general characteristics of mycobacteria

A

Slender, slightly curved or straight, rod-shaped organisms

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3
Q

is mycobacteria non motile or motile?

A

non-motile (—remember non-motile as it only stays at lungs btch)

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4
Q

is it gram negative or positive>

A

gram positive PURPLE just like the color of the lungs

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5
Q

is its non spore forming or no?

A

non spore forming, deadly don’t need spores anymore

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6
Q

what’s something distinct on its cell wall?

A

extremely high lipid content

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7
Q

describe its staining capabality

A

can resist decolorization of acid ethanol and heat must be applied when staining, cant do it with basic dyes

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8
Q

aerobic or anaerobic?

A

Strictly AEROBIC, but increased carbon dioxide (CO2) will enhance the growth of some species.

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9
Q

one of the mycobacteria pathogenic for humans, fails to grow in vitro

A

M. leprae

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10
Q

how many weeks do mycobacteria grow when incubated on complex media at specific optimal temperatures

A

2-6 weeks

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11
Q

PERSONAL SAFETY:

The administration of the microbiology laboratory must ensure that each employee is:
1.
2.
3.
4.
5.

A

(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

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12
Q

Ventilation: _____ air pressure

A

negative

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13
Q

Biological safety cabinet requiremnets

A

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

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14
Q

The _____ is the single most important piece of equipment in a mycobacteriology laboratory

A

biological safety cabinet

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15
Q

Minimum level of respiratory protection

A

N-95 mask

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16
Q

Minimum level of respiratory protection:

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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17
Q

USE OF PROPER DISINFECTANT:

sodium hypochlorite concentration

A

0.1 - 0.5%

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18
Q

USE OF PROPER DISINFECTANT:
contact time of 0.1 - 0.5% sodium hypochlorite

A

10 - 30 mns

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19
Q

USE OF PROPER DISINFECTANT:
phenol concentration

A

5%

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20
Q

USE OF PROPER DISINFECTANT:
contact time of 5% phenol

A

10 -30 mns

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21
Q

USE OF PROPER DISINFECTANT:

a phenol soap mixtures containing _____ or other ______

A

orthophenol or other ohenolic derivatives

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22
Q

USE OF PROPER DISINFECTANT:

phenol soap mixtures containing orthophenol or other phenol derivatives contact time

A

10 - 30 mns

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23
Q

USE OF PROPER DISINFECTANT:
concentration of formaldehyde or glutaraldehyde

A

3-8% formaldehyde and 2% glutaraldehyde

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24
Q

USE OF PROPER DISINFECTANT:
contact time for 3-8% formaldehyde or 2% glutaraldehyde

A

atleast 30mns

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25
Q

most common specimen in mycobacteria test

A

sputum and bronchial aspirates

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26
Q

early-morning specimen should be collected on how many days

A

3 consecutive days

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27
Q

volume of sputum needed

A

5-10ml

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28
Q

is collected when sputum is not available

A

Bronchial washing, bronchoalveolar lavage (BAL), or transbronchial biopsy

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29
Q

is used for patients who have trouble producing sputum spontaneously. The patient inhales nebulized hypertonic saline solution which liquefies airways secretion. It promotes coughing and it allows expectoration of respiratory secretions

A

Sputum induction

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30
Q

what to do when there’s a delay in processing

A

refrigerate

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31
Q

how many samples are needed to confirm a diagnosis

A

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

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32
Q

additional specimens are needed for culture confirmation if

A

When none or only one of the first three sputum smears is positiv

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33
Q

Decontamination and digestion agents:
concentration of sodium hydroxide

A

4-2% sodium hydroxide SERVES AS DG AND DC agent

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34
Q

a mucolytic digestion agent, when it is combined with NaOH, it facilitates the contamination by further digesting muco-purulent specimens which allows the sodium hydroxide to penetrate

A

N-Acetyl-L-Cysteine

35
Q

aka sputolysin; same with NALC (DG)

A

Dithiothreitol

36
Q

a decontamination agent aside from what is mentioned.

A

Benzalkonium chloride (Zephiran)

37
Q

decontaminate specimens contaminated with Pseudomonas aeruginosa, , such as sputum specimens from patients with CF

A

5% Oxalic acid

38
Q

in afb staining, giv ethe size of the bacterial smear

A

2 cm long and 1 cm wide

39
Q

more sensitive than carbolfuchsin stain

A

Auramine or Auramine-rhodamine
Fluorochrome stains

40
Q

what microscope is needed in Auramine or Auramine-rhodamine
Fluorochrome stains

A

Fluorescence microscope

41
Q

a positive mycobacteria under fluorescence microscope

A

bright, yellow-orange bacilli against a dark background

42
Q

percentage comparison of auramine-rhodamine fluorochrome stains than other stain

A

18%

43
Q

Partially acid-fast organisms

A

● Nocardia spp.
● Legionella micdadei
● Rhodococcus spp.

44
Q

carbon dioxide concentration requirement

A

5-10%

45
Q

media pH for culture media

A

pH between 6.5 and 6.8

46
Q

among the mycobacteria species, which one has the longest replication time

A

M. tuberculosis has the longest replication time

47
Q

Three general types of culture media:

A

Egg-based media
Serum albumin agar media
Liquid media

48
Q

Egg based media that is most commonly used in clinical laboratory

A

LJ media

49
Q

3 egg based media

A

LJ MEDIA
Petragnani media
American Thoracic Society (ATS) media

50
Q

Each egg based media contains ______

A

Malachite green

51
Q

Egg based media inhibits _____ bacteria

A

Gram-positive

52
Q

Selective media that contain antimicrobial
agents - Gruft modification of LJ and
Mycobactosel

A

American Thoracic Society (ATS) media

53
Q

2 Serum Albumin Agar Media

A
  1. Middlebrook 7H10
  2. Middlebrook 7H11 agar
54
Q

Middlebrook 7H11 agar contains ____% of ______

A

0.1% casein hydrolysate

55
Q

improves the recovery of
isoniazid-resistant strains of M. tuberculosis

A

The Middlebrook 7H11 agar that contains 0.1% casein
hydrolysate

56
Q

Serum albumin agar media

Both excess heat and exposure of the prepared media
to light can result in the release of _____, which
is toxic to mycobacterial growth.

A

formaldehyde

57
Q

Liquid media for mycobacteria

A
  1. Middlebrook 7H9 broth
  2. Dubos Tween Albumin
58
Q

Mycobacterium spp. grow more rapidly in what
medium, and it can be used for both primary isolation
and subculturing.

A

Liquid medium

59
Q

The first step is to confirm that the
isolate recovered in broth or on solid media is an
_____ by performing an acid-fast stain.

A

acid-fast organism

60
Q

General appearance of mycobacteria

A

smooth and soft or
rough and friable appearance

61
Q

It has a rough often exhibit a prominent
patterned texture

A

Mycobacterium tuberculosis

62
Q

A patterned texture of mycobacterium tuberculosis is called

A

cording (curved strands
of bacilli)

63
Q

It has a variable appearance
with glossy whitish colonies often occurring with smaller
translucent colonies

A

Mycobacterium avium complex

64
Q

Different growth rates that are determined by growth in 7 days

A

Rapid and slow growers

65
Q

Species that grow best at 30°C to 32°C

A

M. marinum, M. ulcerans and M. haemophilum

66
Q

Species that grow best at 42°C

A

M. xenopi

67
Q

Photoreactivity is divided into 3 groups

A
  1. Photochoromogens
  2. Scotochromogens
  3. Nonchromogenic or nonphotochromogenic
68
Q

Photoreactivity

-produces carotene pigment on exposure to light
- color changes from pale yellow to orange

A

Photochoromogens

69
Q

Produce pigment in the light or dark

A

Scotochromogens

70
Q

-buff (tan) colonies; non photoreactive
- Exposure to light does not induce pigment
formation

A

Nonchromogenic or nonphotochromogenic

71
Q

Example of nonchromogenic or nonphotochromogenic

A

Mycobacterium tuberculosis

72
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

73
Q

Organism positive in niacin accumulation

A

M. Tuberculosis

74
Q

Why M.tuberculosis is easily detected by niacin accumulation

A

M.tuberculosis produced high free niacin (nicotinic acid), and it lacks NIACIN-CONNECTING ENZYME . These niacin reacts with cyanogen bromide in the presence of amine to form yellow pigmented compound

75
Q

Positive reaction of nitrate reduction

A

Red pigment

76
Q

Species positive in nitrate reduction

A

M. kansasii, M. szulgai, M. fortuitum, and
M. tuberculosis

77
Q

Enzyme in nitrate reduction

A

Nitrate reductase

78
Q

Do mycobacterium are catalase positive?

A

Yes

79
Q

In catalase test, what is the temperature and time for heating the culture?

A

68°C for 20mns

80
Q

Reagent in catalase test

A

30% hydrogen peroxide

81
Q

Medium used in catalase test

A

Tween 80

82
Q

Test to distinguish scotochromogenic and
nonphotochromogenic bacteria

A

Hydrolysis of tween 80

83
Q

Hydrolysis of tween 80 detects the ability of mycobacteria to split the detergent tween 80 into _____ and ____ by the presence of enzyme lipase

A

Oleic acid and polyoxyethylated

84
Q

PH indicator of hydrolysis of tween 80

A

Neutral red