BACTE LAB - AFS Flashcards

1
Q

Slides must be

A
new
clean
free from grease
free from fingerprints
unscratched
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2
Q

what to write on the frosted end of the slide

A

laboratory register serial number

order number of the sputum specimen

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3
Q

type of pencil to use on unfrosted slides

A

diamond pencil, left end of the slide

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4
Q

what part of the sputum must be taken

A

yellowish purulent part

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5
Q

smear shape

A

oval

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6
Q

smear size

A

2 cm wide x 3 cm length

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7
Q

the smear size corresponds to how many visual fields

A

150, to be counted in one length

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8
Q

if wire loop was used instead of applicator stick, dip it in ___

A

alcohol washed-sand bottle

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9
Q

clean the wire loop in a flask containing ___ before sterilizing in a flame

A

70% - 90% alcohol with glass beads or sand

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10
Q

for accidental contamination with sputum,

hand:

A

wash with soap and water

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11
Q

for accidental contamination with sputum,

cloth:

A

spray with 5% phenol OR
Soak in disinfectant OR
Autoclave OR
Boil

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12
Q

for accidental contamination with sputum,

Surface of container,

A

wear rubber gloves before handling it

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13
Q

for accidental contamination with sputum,

bench of floor

A

spray with 5% phenol or Lysol

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14
Q

How to dry the smears

A

air dry, not in direct sunlight or over a flame

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15
Q

Elements of Quality Smear

A
Quality of sputum
size of smear
thickness of smear
evenness of smear
staining technique
cleanness of slide
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16
Q

What will happen if during fixation the slide was heated for too long or kept stationary

A

smear will be scorched

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17
Q

a good stained smear by ZN method shows ___

A

strong red AFB, against weak blue background

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18
Q

It is not possible to decolorize if _____ are used

A

cold watery acids

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19
Q

To prepare 0.3% Ziehl’s carbol fuchsin working solution, mix

A

10 ml solution A and 90 ml solution B

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20
Q

Solution A of Ziehl’s carbol fuchsin

A

Fuchsin Alcoholic Stock Solution

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21
Q

Solution A of Ziehl’s carbol fuchsin components

A

3g basic fuchsin

95% alcohol UP to 100 mL

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22
Q

Solution A of Ziehl’s carbol fuchsin NAME

A

Aqueous Phenol Solution

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23
Q

Solution A of Ziehl’s carbol fuchsin components

A

Phenol crystals 5g

Distilled water up to 90 mL

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24
Q

Before adding water, liquefy the phenol crystals by

A

gentle heating

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25
Q

Decolorizing Agent Solutions

A

Acid-alcohol solution

25% Aqueous Sulfuric Acid Solution

26
Q

Acid-alcohol solution components

A

95% alcohol — 970 mL

35% HCl — 30 mL

27
Q

25% Aqueous Sulfuric Acid Solution components

A

distilled water 300 ml

conc. sulfuric acid 100 ml

28
Q

0.3% Methylene Blue Counterstaining Solution components

A

0.3 g methylene blue chloride

distilled water up to 100 mL

29
Q

ZN method requires staining for ___ min

A

10

30
Q

ZN method requires decolorizing for ___ min

A

approx 3 min

31
Q

ZN method requires counterstaining for ___ min

A

not more than 1 min

32
Q

what replaced carbon fuchsin in fluorescence staining

A

fluorescent dye

33
Q

examples of fluorescent dye

A

auramine-O
rhodamine
auramine-rhodamine
acridine orange

34
Q

counterstain in fluorescence staining

A

potassium permanganate

35
Q

describe the decolorize in fluorescence staining

A

milder

36
Q

with auramine staining, the bacilli appears as (color)

A

slender bright yellow luminous rods against a dark background

37
Q

identification of mycobacteria with auramine O is due to the

A

affinity of mycolic acid in the cell walls for fluorochromes

38
Q

light produced by a substance when it is stimulated by another light

A

fluorescence

39
Q

fluorescence called cold light because

A

does not come from a hot source like an incandescent light bulb

40
Q

dyes which have the property of absorbing light rays of shorter wavelength and emitting light rays of longer wavelength

A

fluorescent dye such as auramine O

41
Q

source of light

A

mercury vapour lamp

42
Q

by meas of ____

A

only light rays of shorter wave lengths are allowed to emerge

43
Q

rays of ___ wavelengths used for fluorescence microscopy

A

shorter

44
Q

Heat slides until

A

Vapor starts to rise and metallic sheen appears

44
Q

Heat slides until

A

Vapor starts to rise and metallic sheen appeara

45
Q

Let the carbol fuchsin staim stand for —min

A

10 min

46
Q

Applying time for counterstaining reagent depends on (3)

A

Quality of specimen
Thickness of smear
Concentration of reagent

47
Q

Poor quality smears can lead to —-

A

False results

48
Q

If the smear is dark blue, this means that,

A

The smear is too thick

49
Q

Employed to highlight the stained organisms for easier recognition

A

Counterstain

50
Q

Examples of fluorescent dye

A

Auramine-O
Rhodamine
Auramine-rhodamine
Acridine orange

51
Q

Counterstain in fluorescence microscopy

A

Potassium permanganate

52
Q

Useful to quench background fluorescene

A

Counterstain (potassium permanganate)

53
Q

Fluorescent dyes are also called

A

Fluorochromes

54
Q

Principle lf auramine staining

A

Affinity of mycolic acids for fluorochromes

55
Q

After smearing sputum, let the slide air dry for —- min

A

15-20 min

56
Q

T or F

Wet slides can produce aerosols if disturbed

A

T

57
Q

When is Bsc required

A

Large volume of positive sputum sx to be handled
In cultures
In drug susceptibility testing

58
Q

Specimens can be discarded by (2)

A

Burying after chemical disinfection or autoclaving

Safe commercial waste collection services

59
Q

Discard waste in a deep pit of at least — m depth

A

1.5

60
Q

Limit the number of slides in each staining batch to a maximum of —

A

12