Mycobacteria Flashcards

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1
Q

why do these cells need acid fast stain?

A

cell wall has high lipid content, rich in mycolic acids

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2
Q

what are the environmental requirements?

A

strictly aerobic
increased CO2 enhance growth
require 2-6 weeks incubation

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3
Q

what organisms are a part of the mycobacterium tuberculosis complex?

A

tuberculosis
bovis
africanum
microti

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4
Q

what are some characteristics of the m. tuberculosis complex?

A

all cause tuberculosis
slow growers
nonpigmented

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5
Q

what are symptoms of primary tuberculosis?

A
productive cough
low grade fever
night sweats
fatigue
anorexia
weight loss
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6
Q

how is tuberculosis transmitted?

A

air droplets

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7
Q

what is skeletal TB of the spine called?

A

Pott disease

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8
Q

what is the treatment for tuberculosis?

A

9 month course of isoniazid and rifampin

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9
Q

what causes treatment failures?

A

patient noncompliance

drug resistance

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10
Q

what organism has serpentine cords on middlebrook after 5 - 10 days

A

M. tuberculosis

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11
Q

how long does it take for M. tuberculosis to grow on LJ

A

14 -28 days at 37

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12
Q
niacin +
nitrate +
inhibited by NAP
catalase -
Tween 80 >5 days
A

tuberculosis

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13
Q

niacin -
nitrate -
tween 80 > 5 days

A

bovis

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14
Q

what groups make up the NTM?

A

photochromogens
scotochromogens
non photochromogens
rapid growers

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15
Q

what organisms are photochromogens?

A

kansasii
marinum
asiaticum

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16
Q

characteristics of photochromogens

A

dark = buff
light = pigmented
potential pathogens - pulmonary disease

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17
Q

what photochromogen causes cutaneous disease after exposure to contaminated water

A

marinum

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18
Q

what organisms are scotochromogens

A

gordonae
scrofulaceum
szulgai

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19
Q

characteristics of scotochromogens

A

pigmented in light and dark

most nonpathogenic

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20
Q

what organisms are nonpathogenic nonphotochromogens

A

terrae
triviale
nonchromogenicum
gastri

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21
Q

what organisms are rare pathogens in nonphotochromogen group?

A

shimoidei
celatum
xenopi
ulcerans

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22
Q

what organisms are the most common pathogens in the nonphotochromogen group?

A

mycobacterium avium complex

avium, intracellulare

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23
Q

how is the MAC spread?

A

inhalation or ingestion

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24
Q

what is the reservoir for MAC?

A

water

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25
Q

what organisms are rapid growers?

A

fortuitum
chelonae
smegmatis

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26
Q

what organism causes leprosy (hansens disease)?

A

leprae

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27
Q

how is leprosy transmitted?

A

inhalation

person to person contact

28
Q

photo
nitrate +
niacin -
Tween 80 < 5 days

A

kansasii

29
Q

photo
nitrate -
niacin V
Tween 80 < 5 days

A

marinum

30
Q

scoto
niacin -
nitrate -

A

scrofulaceum

31
Q

characteristics of m. leprae

A

cannot be grown in vitro
only cultivate in armadillos and mouse footpads
optimal growth temp 30

32
Q

what temperature is required for marinum culture

A

30 - 32 for 7 -21 days

33
Q

Specimens that require digestion

A

Sputum and other specimens with normal flora

34
Q

Incubation requirements

A

35

5 - 10% CO2

35
Q

Incubation period for slow growers

A

2 - 6 weeks

36
Q

Ziehl neelsen:
Primary stain
Decolorizer
Counterstain

A

Carbolfuschin
Acid alcohol
Methylene blue

37
Q

What does ziehl neelsen stain require

A

Heat

38
Q

Kinyoun:
Primary stain
Decolorizer
Counterstain

A

Carbolfuschin
Acid alcohol
Methylene blue

39
Q

Fluorochrome:
Primary stain
Decolorizer
Counterstain

A

Auramine-rhodamine
Acid alcohol
Potassium permanganate

40
Q

organisms that are niacin -

A

tuberculosis

simiae

41
Q

nitrate + organisms

A
tuberculosis
kansasii
szulgai
fortuitum
flavescens
42
Q

tween 80 +

A

kansasii (6 hours)

gordonae

43
Q

urease +

A

scrofulaceum
gastri
bovis

44
Q

scoto only positive for Tween 80 and heat stable catalase

A

gordonae

45
Q

what is the only thing M. avium-intracellulare positive for?

A

pyrazinamidase

46
Q

what patients are at increased risk of tuberculosis

A

patients with diminished cell mediated immunity

47
Q

What about the cell wall allows mycobacterium to resist decolorization

A

Lipids and mycolic acid

48
Q

Safety requirements

A

BSL3
PPE
tb test every year
Separate room

49
Q

Best specimen for sputum

A

First morning deep expectorated cough

50
Q

What organism is being looked for in fecal specimens

A

Avium-intracellulare

51
Q

What condition is avium- intracellulare associated with

A

AIDS

52
Q

Reagents for decontamination

A

N-acetyl-L-cysteine
Dithiothreitol
2% NaOH
4% NaOH

53
Q

What does digestion of sputum do

A

Split disulfide bonds in mucin

54
Q

Primary host defense in tuberculosis

A

Cell mediated immunity

55
Q

How long does it take for a healthy person to show signs of tuberculosis infection

A

2 weeks - 3 months

56
Q

What forms granulomas in TB

A

T cells and macrophages

57
Q

Tap water bacillus

A

Gordonae

58
Q

preferred carbon source

A

glycerol

59
Q

mucolytic reagent

A

N-acetyl-L-cystine-NaOH

60
Q

rhodamine staining: potassium permanaganate function

A

quenching reagent

61
Q

why must middlebrook media be stored in the dark?

A

exposure to light may cause formaldehyde production

62
Q

method used to process specimens contaminated with pseudomonas

A

oxalic acid

63
Q

presumptive diagnosis of hansens disease

A

detect weakly acid fast bacilli in infected tissue

64
Q

nonchromogen grows best at 42

highly resistant to antibiotics

A

xenopi

65
Q

how are intracellulare and avium differentiated?

A

DNA probe

66
Q

organism that does not fluoresce on fluorochrome stain

A

fortuitum