Mycobacteria Flashcards
1
Q
What is the most familiar species of Mycobacterium?
A
- Mycobacterium tuberculosis
- Mycobacterium leprae
2
Q
What is other name for leprosy?
A
- Hansen Disease
3
Q
What is the counterstain for acid fast staining?
A
- methylene blue
4
Q
When there is a delay in the processing of the culture specimen, what should be done?
A
- refrigeration
5
Q
The inhibitor present in egg-based media
A
Malachite green
6
Q
Positive result for nitrate reduction
A
Red color
7
Q
Media that enhanced the isolation of isoniazid resistant strain of MTB
A
Middlebrook 7H11
8
Q
The positive Niacin reaction is indicated by
A
Development of yellow color
9
Q
The optimal growth temperature for M. xenopi
A
42 degrees celcius
10
Q
Which strain is used for the fluorescent staining method for the identification of Mycobacteria?
A
Auramine
11
Q
What is the average incubation period for slow growing pathogenic Mycobacteria?
A
2-6 weeks
12
Q
Mycobacterium tuberculosis is classified as
A
Nonphotochromogen
13
Q
MTB reaction for semiquantitative catalase test
A
> 45 mm bubble column
14
Q
Mycobacterium tuberculosis is also known as
A
Koch’s bacillus
15
Q
Remains a major cause of morbidity and mortality in the world today
A
Tuberculosis
16
Q
Other name of Environmental mycobacteria?
A
Nontuberculous mycobacterium
17
Q
What is the morphology of mycobacterium?
A
Gram positive, slender, slightly curved or straight, rod-shaped
18
Q
Mycobacteria resist staining with
A
Aniline dyes such as Gram stain
19
Q
Mycobacteria is resist decolorization with
A
Acid ethanol
20
Q
What is the oxygen requirement for mycobacterium?
A
Strictly aerobic
21
Q
Fails to grow in vitro
A
M. leprae
22
Q
What does a mycobacterium laboratory should have?
A
Non-recirculating ventilation system
23
Q
What is the required respiratory protection or mask?
A
N-95 mask
24
Q
What is the most important piece of equipment in the microbiology laboratory?
A
Biological safety cabinet
25
Negative pressure cabinet
Class I or biological safety cabinet class 1
26
Vertical laminar flow cabinets
Class II or biological safety cabinet class II
27
What is the contact time for proper disinfectants?
10-30 minutes
28
What is the concentration of sodium hypochlorite?
0.1-0.5%
29
What is the concentration for phenol?
5%
30
What is the concentration for formaldehyde and for glutaraldehyde?
3-8% and 2%
31
What is the contact time for formaldehyde and glutaraldehyde?
At least 30 mins
32
What are the specimen for collection?
- urine
- feces
- blood
- CSF
- respiratory specimens
- tissue biopsies
- aspirations of any tissue or organ
33
What are the most common specimen for mycobacterium?
Sputum and bronchial aspirates
34
What is the process of collecting sputum specimen?
- Early morning specimen
- Should be collected on three consecutive days
35
What is the volume of sputum?
5-10 mL
36
What is the recommended container?
Sterile, wide-mouth cup with tightly fitted lid
37
Patients inhale ____to allow them to cough
Nebulized hypertonic saline
38
This cell wall of mycobacteria makes them somewhat less suceptible to the killing action of the various chemicals
High lipid content
39
What is the most popular reagent in decontamination?
2-4% sodium hydroxide
40
Enumerate the agents we can use for Digestion agents
- 4-2% sodium hydroxide
- N-Acetyl-L-Cysteine (NALC)
- Dithiothreitol
41
What is the colony appearance of mycobacterium in afb staining?
Beaded appearance
42
Primary stain
Carbolfuschin
43
Decolorizing agent
Acid alcohol
44
What is the color of Acid fast organisms?
Red
45
What is the color of non-acid fast?
Blue
46
Application of heat with carbolfuschin stain. Tends to provide more consistent results
Ziehl-Neelsen stain
47
Cold stain. Tergitol is used as a mordant.
Kinyoun stain
48
What is the positive color for fluorochrome stain or auramine-rhodamine stain
Yellow-orange bacilli
49
What genus can use AFB stain?
Nocardia spp
Legionella micdadei
Rhodococcus spp
50
What is the pH level of mycobacteria?
6.5-6.8
51
What are the three general types of culture media?
- Egg-based media
- Serum Albumin agar media
- Liquid media
52
What media is most used in clinical laboratory?
Lowenstein Jensen Medium
53
Enumerate the egg-based media
- lowenstein jensen media
- petragnani media
- American thoracic society media
54
Rough often exhibit a prominent patterned texture referred to as cording
M. tuberculosis
55
Variable appearance with glossy whitish colonies often occuring with smaller translucent colonies
M. avium complex
56
What is the general morphology of mycobacterium?
Smooth and soft or rough and friable appearance
57
Produce carotene pigment on exposure to light
Photochromogens
58
Produce pigment in the light or dark
Scotochromogens
59
Buff or tan colonies
Nonchromogenic or nonphotochromogenic
60
Posses th enzyme that converts free niacin to niacin ribonucleotide
Niacin accumulation
61
Culture media of choice for niacin accumulation
Egg agar
62
What is the negative result of niacin accumulation?
Colorless
63
The production of nitroreductase which catalyzes the reduction of nitrate to nitrite
Nitrate reduction
64
What organisms tested positive for nitrate reduction?
- mycobacterium kansasii
- mycobacterium szulgai
- mycobacterium fortuitum
- mycobacterium tuberculosis
65
What is the reagent of catalase test?
30% hydrogen peroxide
66
What is the medium used in catalase test and hydrolysis of tween 80?
Tween 80
67
Production 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 test
68
Who is positive in semiquantitative catalase test?
Mycobacterium tuberculosis
69
Test to distinguish scotochromogenic and nonphotochromogenic bacteria
Hydrolysis of tween 80
70
What is the pH indicator of hydrolysis of tween 80?
Neutral red
71
Positive color of hydrolysis of tween 80
Pink color
72
Detecting the ability of mycobacteria to split rhe detergent tweeen 80 into oleic acid and polyoxyethylared sorbitol by the presence of enzyme lipase
Hydrolysis of tween 80
73
Reduction of colorless potassium tellurite to black merallic tellurium
Tellurite reduction test
74
Positive in tellurite reduction test
Mycobacterium avium
75
One of the oldest documented communicable diseases
Mycobacterium tuberculosis
76
Mode of transmission of tuberculosis
Airborne droplets
77
It is the initial infection.
Positive in PPD
Primary tuberculosis
78
Detected by measuring nicotinic acid which reacts with cyanogen bromide in the presence of aniline to form a yellow compound
Niacin accumulation
79
Performed as with the method used for enteronacteriaceae
Nitrate reduction
80
The mycobacterium is eradicated by the host cellular immune response or walled off in a granuloma in the lung
Primary tuberculosis
81
Occurs when there is an alteration or suppression of the cellular immune system in the infected host that favors replication of the bacilli and progression to disease
Reactivation tuberculosis
82
Common presentation in individuals with HIV
Extra pulmonary tuberculosis
83
Widespread dissemination of mycobacterium tuberculosis via hematogenous spread
Miliary tuberculosis
84
Skeletal tuberculosis of the skin also referred to as
Pott disease
85
What is the treatment for TB
9-month course of therapy with isoniazid and rifampin
86
Produces TB primarily in cattle
Mycobacterium bovis
87
BCG vaccine
Mycobacterium bovis Calmette-Guerin
88
Causative agent of hansen disease or leprosy
Mycobacterium leprae
89
Tissue or test animal for culture
Armadillo or foot pad
90
What are the 3 types of leprosy
1. Tuberculoid leprosy
2. Lepromatous leprosy
3. Borderline type of leprosy
91
Diagnostic skin test for M. leprae
Lepromin skin test
92
What are the two types of lepromin reaction?
1. Fernandez reaction
2. Mitsuda reaction
93
Early reaction; reaction after 24-28 gours
Fernandez reaction
94
3-4 weeks reaction
Mitsuda reaction
95
Small amount of organisms in skin lesion
BENIGN type
Positive for lepromin skin test
Tuberculoid leprosy
96
What is other names for tuberculoid leprosy?
Anesthetic or neural leprosy
97
Abundant organisms in skin lesion
MALIGNANT
negative in lepromin skin test
Lepromatous leprosy
98
Lion head appearance
Lepromatous leprosy
99
No manifestation.
Once activated will cause manifestation
Borderline type of leprosy
100
What are the treatment for leprosy
- dapsone
- clofazimine
- rifampin
101
What are the four groups of tubercle bacilli?
1. Photochromogen
2. Scotochromogen
3. Nonphotochromogen
4. Rapid growers
102
Color of scotochromogen
Light or dark orange/yellow
103
What is the growt of scotochromogen?
10-21 days
104
Who are the members of scotochromogen?
- mycobacterium scotofulaceum
- mycobacterium gordonae
105
Color of photochromogen
Light orange/ yellow or dark cream/ buff
106
Growth of photochromogen
20-21 days
107
Members of photochromogen
- mycobacterium kansasii
- mycobacterium marinum
- mycobacterium simiae
- mycobacterium balnei
108
Color or nonphotochromogen
Light or dark cream / buff
109
Growth of Nonphotochromogen
10-21 days
110
Members of Nonphotochromogen
- mycobacterium avium
- mycobacterium ulcerans
- mycobacterium xenopi
111
Growth of rapid growers
3-7 days
112
Members of rapid growers
- mycobacterium fortuitum
