Exam 4 (Mycobacteria spp.) Flashcards
1
Q
Mycobacteria are acid fast due to:
A
High lipid content
2
Q
Mycobacteria are Gram___ non-spore forming, slender, slow-growing___, obligate ___:
A
Gram+/variable
bacilli
obligate aerobes
3
Q
Mycobacteria are divided into these two groups:
A
1) Mycobacterium tuberculosis complex
2) Non-tuberculosis mycobacteria (NTM)
4
Q
T/F
All Mycobacterium tuberculosis complex are slow growers and produce non-pigmented colonies:
A
True
5
Q
List the 8 species within the Mycobacterium tuberculosis complex:q
A
M. tuberculosis M. bovis M. bovis BCG M. africanum M. caprae M. canettii M. microti M. pinnipedii
6
Q
Which species/strain of Mycobacterium tuberculosis complex has been used in live vaccines for over 70 years, and has led to infection in some patients:
A
M. bovis BCG
7
Q
There are over ___ species of NTM, and some transiently colonize __, __, and ___ of healthy humans:
A
130 species
skin, GI, resp tract
8
Q
Do NTM species typically spread person to person:
A
No.
9
Q
What is the classification of NTM:
A
Runyon groups (I- IV)
10
Q
This is an older classification system of NTM based on growth rate, colony morphology and pigment production (caratenoids):
A
Runyon groups
11
Q
Photochromogens belong to Runyon Group___:
A
Group I
12
Q
Scotochromogens belong to Runyon group___:
A
Group II
13
Q
_____produce pigment in dark or light conditions and belong to Runyon group___:
A
Scotochromogens
Group II
14
Q
____are non-pigmented regardless of incubation in dark or light conditions, and belong to Runyon Group___:
A
Non-photochromogens
Group III
15
Q
____take fewer than 7 days to appear on solid media and belong to Runyon group__:
A
Rapid Growers
Group IV
16
Q
Runyon Group IV:
A
Rapid Growers
17
Q
Runyon Group III:
A
Non-photochromogens
18
Q
List the 3 Mycobacteria species that are photochromogens (group I):
A
M. kansasii
M. marinum
M. asiaticum
19
Q
List the 4 Mycobacteria species that are scotochromogens (group II):
A
M. scrofulaceum
M. szulgai
M. gordonae
20
Q
This non-photochromogen is found in hot water taps in hospitals, and causes pulmonary infections and disseminated disease:
A
M. xenopi
21
Q
This scotochromogen can cause cervical adenitis in children:
A
M. scrofulaceum
22
Q
Why are M. avium and M. intracellulare reported in combination, as a complex:
A
On clinical grounds and routine lab methods, they cannot be distinguished from each other
23
Q
Mycobacterium avium complex (MAC) is an important pathogen in ____ patients:
A
AIDS
24
Q
Does pulmonary disease in AIDS patients present with granulomas or tissue death?
A
No.
Patients exhibit increased mucus production, can provide stress on bronchioles and lead to bronchiectasis.
25
Is MAC spread person to person?
No.
26
List the two Mycobacterium species in the Runyon group IV:
M. fortuitum
| M. chelonae
27
What will Runyon group IV species grow on that most other Mycobacteria spp will not:
MacConkey (w/out crystal violet)
28
_____ and ____ from Runyon group ___ are the only 2 species that will grow in 5 days on MacConkey at 37 degrees C:
M. fortuitum
| M. chelonae
29
This is a non-cultivatable nontuberculous mycobacterium, has not been grown in vitro because it is an obligate intracellular bacteria that only survives several minutes in the environment....is found in armadillos and mice:
M. leprae
30
Why can't M. leprae be grown in vitro:
It is an obligate intracellular bacteria.
31
___ causes leprosy and is found in ___ and ___:
M. leprae
| armadillos and mice
32
T/F
| TB is increasing worldwide, and disease progression is becoming more rapid.
True.
| There is a need for rapid isolation/identification.
33
What is the most important factor with growth of Runyon group IV species on MacConkey:
Most important factor is presence of growth in 5 days. Color change is not of great significance.
34
Describe a proper sputum specimen for Mycobacteria testing:
Sputum taken early morning for 3 consecutive days
| **children with TB typically cannot cough up sputum
35
List some specimens for Mycobacteria spp testing:
Virtually any tissue or organ
* sputum
* tissue/granuloma
* urine
* bone, csf, blood, GI, stool
36
T/F
| Specimens from sterile sites can be directly plated to media:
True
| blood, urine, CSF
37
Processing of sputum specimens for acid fast bacteria requires ____/____ followed by ____ and ____ via centrifugation. These steps kill normal flora and also release TB bacteria from cells/mucin:
digestion/decontamination
| neutralization and concentration
38
___: liquefy mucus with mucolytic agents which releases the bacteria from the mucin:
Digestion
39
Decontamination eliminates this:
mixed bacterial flora
40
What makes Mycobacterium resistant to decontamination:
High lipid cell wall
41
_____ with phosphate buffer or H20 is done following the 15 minute digestion/decontamination step:
Neutralization
42
What is used for digestion of mycobacterium:
NaOH
43
In the NALC NaOH method of sputum digestion/decontamination, NaOH is ____ when mixed with _____:
NaOH is reduced to 2% when mixed with NALC
44
____ is the preferred method for sputum digestion/decontamination and requires ____ minute incubation:
NALC NaOH
| 15
45
NALC is a ____ agent, releasing bacteria, while NaOH is both a ____ and ____ agent:
NALC: mucolytic
NaOH: mucolytic/decontaminating agent
46
What is done following the digestion/decontamination step:
add the phosphate buffer followed by 15 mins of centrifugation
47
What stain would be done to mucous specimen:
acid fast
| after digestion, etc
48
What BSL___ lab is used to identify TB, and/or identify all Mycobacteria spp. and perform susceptibility testing:
BSL 3
49
BSL3 BSC and centrifuge room should have ______ walls and work surfaces, ____ air flow, and ____filters vented to outside:
non-permeable
directional
HEPA
50
What must be done with protective clothing after working in a BSL3:
removed/autoclaved
51
High ____cell content of Mycobacteria binds _____ and resists ____ by acid-alcohol:
Lipid
Fuchsin dye
decolorization
52
List the two methods of acid fast staining:
* Ziehl-Nelson (hot)
| * Kinyoun (cold)
53
This acid fast staining method uses a higher concentration of phenol in the primary stain to accelerate the staining process and thus does not require heat:
Kinyoun (cold)
54
Fluorochrome stain is used for Mycobacteria spp. because they have an ____ for ____:
affinity for fluorochrome
55
You need to scan at least ____ oil immersion fields before you report a slide as _____:
300
| negative
56
300 oil immersion fields is equivalent to ___ (400x) fields on on a fluorochrome slide:
30
57
For optimal recovery of Mycobacteria spp., you should use at least one _____ and one ____:
one solid media
| one liquid medium
58
List the two liquid media used for Mycobacteria spp:
BACTEC 128 medium
| Middlebrook 7H9 Broth
59
What two solid media should be used for Mycobacteria spp:
* one with agar base (Middebrook 7H10)
| * one with egg-potato base (Lowenstein-Jensen, or Petragnani)
60
Both Lowenstein-Jensen and Petragnani media contain malachite green for this purpose:
Malachite green dye inhibits other microbes (contaminants)
61
How is tube media incubated for Mycobacteria spp:
35 C, dark, 5-10% CO2, humid
| *tube initially in slanted position w/ cap loose for 1 wk to let fluid evaporate and CO2 enter
62
How often should Mycobacteria spp cultures be examined for growth, and when does growth for most species appear on liquid media, and solid media:
examine weekly
liquid: 2 wks
solid: 3-6 weeks
63
___ is often used as a back up if liquid media fails:
solid media
64
M. tuberculosis takes and average of ___ to grow and an additional ___ for susceptibility testing:
2-4 wks
| 2-4 wks
65
A new____ technique by Ghodbane is reducing the cultivation time for M. tuberculosis to as little as 72 hours:;
incubation
| includes microaerophilic conditions
66
What is the immunodiagnostic test for TB and how does it work:
T-SPOT TB blood test
| Wells contain TB specific antigen and thus detect TB activated T cells from blood samples
67
All Mycobacteria produce ___, some species lack the enzyme necessary to convert __ to ___, resulting in high accumulation of niacin in the culture medium:
niacin
| niacin----> niacin ribonucleotide
68
Is the niacin test enough to ID M. tuberculosis:
no
69
With the niacin filter paper test, what color will the broth turn if niacin is present (positive):
yellow
70
Which two species of Mycobacteria are Niacin+:
M. tuberculosis
| M. simiae
71
Only two species of Mycobacteria produce nitroreductase, which catalyzes the reaction of nitrate reduction to nitrite:
M. tuberculosis
| M. kansasii
72
It is very important controls be used for this test, and the M. tuberculosis control has to be strongly positive, otherwise results of unknowns are unreliable:
Nitrate reduction test
73
What enzyme reduces nitrate to nitrite, and which two species have the enzyme:
nitroreductase
M. tuberculosis
M. kansasii
74
Tween 80 hydrolysis is a ____ trade name, and is ___ to certain organisms:
detergent
| toxic
75
This test identifies Mycobacteria possessing a lipase that splits the compound into oleic acid and polyoxyehtylated sorbitol:
Tween 80 hydrolysis
76
How do you perform a Tween 80 hydrolysis test:
* 2 drops Tween 80 added to 1mL saline and inoculated w/ loopful of organism
* incubate 35 C for ~12 days
* Fluid will change from light orange to pink or red if positive
77
What does a positive result look like in Tween 80 hydrolysis:
Fluid will change from light orange to pink or red
78
Which species is a quick positive for Tween 80 hydrolysis, and which are typically negative:
M. kansasii (positive)
| M. tuberculosis complex (negative)
79
T/F
| Most Mycobacteria species produce catalase:
True
80
T/F
| All Mycobacteria species produce a heat stable catalase:
False.
| *Most M. tuberculosis complex organisms do not produce heat stable catalase.(68 degree catalase neg)
81
____: Broth culture medium/automated continuous growth monitoring systems:
BACTEC
82
Positive niacin and nitrate reduction, 68 degree catalase neg, strong acid fast+, rough, dry, buff, non-pigmented on LJ media, slightly curved rods w/ beaded appearance:
M. tuberculosis
83
TB+ cultures are typically kept by the lab for ___ following ID for epidemiological purposes:
6-12 months
84
List the two conventional methods for M. tuberculosis susceptibility testing:
* Liquid broth automated systems (BACTEC)
| * Absolute concentration (provides MIC)
85
Molecular methods for susceptibility testing for M. tuberculosis are testing for the gene/gene mutation that causes ___ resistance:
Rifampin
86
T/F
| Inhalation of a single bacilli has been shown to lead to infection with Tuberculosis:
True
| not necessarily disease though
87
Upon exposure to TB, ____% develop disease, ___ remain with latent infection:
5-10%
| 90%
88
T/F
| One third of the world's population is infected with TB:
True
| latent or active
89
What is it called when person with latent TB has disease manifestation at a later time:
Secondary (reactivation) TB
90
Define miliary TB:
spread to other organs hematogenously
91
TB bacteria travel from respiratory droplets to alveoli, they are taken up by ___ which are unable to kill them, which leads to eventual formation of ____:
macrophages
| granulomas
92
List the two clinical screening methods for TB:
* QuantiFERON-TB Gold In-Tube test
| * Purified Protein Derivative (PPD)
93
Treatment consists of using ___ drugs in combination for ___ months:
* Isoniazid
* Rifampin
* Pyrazinamide
* Ethambuterol
2-3 drugs
9-12 months
*problems with patient compliance and drug resistance
94
Multidrug resistant TB is resistant to ___ and ____:
Isoniazid and Rifampin
95
Studies being done on association of ____ between Johne's disease in cattle and Crohn's disease in humans:
M. avium, subspecies paratuberculosis
96
M. leprae causes ____ aka ____:
leprosy
| Hansen's disease
97
This is a chronic disease of the skin, mucous membranes, nerve tissue, primary reservoir is humans, is usually associated with tropical climates, and is caused by an obligate intracellular bacteria:
Leprosy aka Hansen's disease
| M. leprae
98
What's the significance of Molkai Hawaii:
Contact with infected human skin/nasal secretions transmits leprosy
99
Leprosy can be found in this part of the US, and ___serve as a reservoir:
SW
| armadillos
100
Would a skin biopsy be part of confirming leprosy:
Yes
101
Can leprosy be cured:
Yes.
| Antibiotics such as Clofazimie, Rifampin, Dapsone
