Mycobacteriology Exam Flashcards

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1
Q

What organisms stain on acid fast?

A

Myvobacterium

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2
Q

What are the advantages of Carofuchsion and fluorescent stains?

A

CF: Stains all Fluor: More sensitive for MTB, easier to see fewer organisms.

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3
Q

What are the disadvantages of Carofuchsion and fluorescent stains?

A

CF: Less sensitive Fluor: Poor for rapid

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4
Q

Why do acid fast bacteria stain acid fast?

A

Cell wall rich in lipid which resists decolorization

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5
Q

What is a tuberculous granuloma?

A

Walling off = TB(+), Lymphs produce gamma interferon

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6
Q

Location of lung were types of TB (primary and secondary) are located.

A

Primary: Near middle of lung where air circulates Secondary: Near top of lung where oxygen is

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7
Q

Look at pie char for racial distribution

A

White: 16% Black: 25% Mexican: 29% Hawaii: 1% Asian: 28% Indian: 1%

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8
Q

US born

A

White: 32% Black: 42% Mexican: 19% Hawaii:

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9
Q

Where is the highest rate of TB found?

A

South & Southeast Asia
East Asia and Pacific
Sub-Saharan Africa

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10
Q

What are the 6 populations with increased MTB infections?

A

AIDS, Drugg users, Nursing homes, Homeless shelters, Immigrants

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11
Q

What are the sputum processing guidelines for ID of MTB?

A

Early morning, 3-5 specimens preferably 24hrs apart. REFRIGERATE.
Add N-acetyl L-cysteine (digestion=frees) and 2% NaOH. Vortex (decontamination) and sit 20 min.
Add phosphate buffer and centrifuge 3000-3800g Decant and add 2ml Phosphate buffer.
Screen for MTB with Fluorescent Acid fast

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12
Q

What are the methods for ID of M. Leprae?

A

There are not any Lab methods. (Dermatologist can Biopsy and acid fast to ID organisms if present)

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13
Q

What is the medium for MGIT, BacTALERT and BACTEC.

A

MiddleBrook broth

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14
Q

Define Rapid grower

A

Grow in

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15
Q

What is the most reliable biochemical test for ID of MTB?

A

Niacin

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16
Q

What is the least reliable Biochemical for ID of MTB?

A

Nitrate

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17
Q

What is a Phtochromogen?

A

Yellow w/ light

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18
Q

What is a Nonchromogen?

A

Never produces a pigment

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19
Q

What is a Scotochromogen?

A

Produces pigment independently of light exposure

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20
Q

Memorize the pathogenic M. species table on powerpoint 2 page 2, first slide.

A

This table is very important, I talked with Katie about tit and knowing it will be very useful

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21
Q

How do you ID MTB?

A

Niacin(+), = go to bank

Nitrate(+), T2H resistant, heat stable catalase(-) unless INH resistant

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22
Q

Why would RNA be used over DNA?

A

There is a lot more RNA than DNA.

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23
Q

What is an accuprobe and what does it target

A

RNA from MEDIA

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24
Q

What is a Cepheid (gene expert) and what does it target?

A

DNA directly from specimen

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25
Q

What are the advantages and disadvantages of amplified DNA

A

Uses clinical specimen so it is faster but it uses DNA which is not as sensitive

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26
Q

Runyon group 1

A

Photocromogens

27
Q

Runyon group 2

A

Scotochromogens

28
Q

Runyon group 3

A

Nonchromogens

29
Q

Runyon group 4

A

Rapid Growers

30
Q

What are the 3 members of MTB complex?

A

MTB, M. Bovis, M. africanum

31
Q

What is the criteria for skin culturing?

A

37 AND 30-32 degrees

32
Q

What bacteria is inhibited by T2H?

A

M. Bovis

33
Q

What bacteria are nitrate pos?

A

MTB, M. kansasii, M. szulgai, M. fortuytum

34
Q

How do pathogenic and nonpathogenic scotochromogens react in urease generally?

A

Urease neg scotochromogens are usually pathogens

35
Q

Which test differentiate MTB and M. Bovis?

A

Niacin, T2H (nitrate)

36
Q

What bacteria grows best less than 35-37?

A

M. marinum

37
Q

What bacteria grows best at greater than 37?

A

M. xenopi

38
Q

How does the TB process make positive testing results?

A

Macrophage is infected with TB, Lymphs surround and produce interferon gamma (=granuloma)
Gamma interferon is measured by ELISA, reliable on vaccinated individuals and AIDS

39
Q

How is cord factor used to ID and what is its importance?

A

ID’s TB and increases its virulence

40
Q

What are the special requirements of M. Haemophilum?

A

Needs heme

41
Q

What is the appearance of MTB on agar plates?

A

Rough and buff

42
Q

What is the appearance of M. kansasii on agar plates?

A

Produces pigment in light

43
Q

What is the appearance of M. xenopi on agar plates?

A

Always produces pigment

44
Q

What is the appearance of M. fortuitum on agar plates?

A

Rapid grower, may be rusty colored

45
Q

Explain the following about M. bovis: how it affects the TB skin test, how it is used in cancer patients, how it is identified, and relationship to BCG

A

Gives (+) TB test, used in bladder caner patients, inhibited by T2H, attenuated strand for BCG vaccine

46
Q

What are the two solid media used for isolation of mycobacterium?

A

Lowenstein Jensen (LJ) and Middlebrow 7H10

47
Q

What are the 3 types of broth media for isolation?

A

Tactic-MGIT, Organon Teknika-BacAlert, and Bactec 9000

48
Q

What media is used to ID organisms more quickly?

A

Broth

49
Q

What temps are cultures set up at?

A

ALL @ 37, Skin @37 and 30-32

50
Q

What media are all organisms set up in?

A

BOTH

51
Q

What are the results of arylsylfatase nitrate, iron uptake and MAC for M. fortuitum?

A

arylsulfatase(+), nitrate(+), iron uptake(+), and MacConkey(+)

52
Q

What are the results of arylsylfatase nitrate, iron uptake and MAC for M. chelonae?

A

arylsulfatase(+), nitrate(-), iron uptake(-), and MacConkey(-)

53
Q

What are the results of arylsylfatase nitrate, iron uptake and MAC for M. abscesses?

A

arylsulfatase(+), nitrate(-), iron uptake(-), and MacConkey(+)

54
Q

How is tween used to differentiate pathogenic and nonpathogenic scotochromogens?

A

Tween positive are usually nonpathogenic

55
Q

What bacteria are nitrate pos?

A

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

56
Q

What bacteria are in scrofulous wounds in adults?

A

MTB

57
Q

What bacteria are in scrofulous wounds in children?

A

M. scrofulaceum

58
Q

What bacteria is historicaly associated with AIDS patients and isolated from their stools/blood?

A

M. avium

59
Q

What characteristics are used to differentiate organisms into their runyon groups?

A

Pigment production and growth rate

60
Q

What are the 4 probes for mycobacteria ID?

A

TB complex, Avium-intracellulare complex, M. gordonae, and M. Kansasii

61
Q

Where is M. bovid typically found and how is it transmitted?

A

Cows, and transmitted by their products

62
Q

What organisms and characteristics are IDed by the GENExpert?

A

MTB and Rifampin

63
Q

What is the ideal contamination rate for specimens?

A

5%

64
Q

What mycobacteria produces disease similar to MTB and is a photchromogen?

A

M. Kansasii