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Laboratory Gram Stain And Afb Stain Flashcards

1
Q

It is named after the Danish bacteriologist who originally devised it in

A

Hans Christian Gram

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2
Q

It is one of the most important staining techniques in microbiology

A

Gram staining

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3
Q

It is almost always the first test performed for the identification of bacteria.

A

Gram staining

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4
Q

The primary stain of the Gram’s method is

A

Crystal violet

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5
Q

Crystal violet is sometimes substituted with

A

Methylene blue

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6
Q

The microorganisms that are stained by
the Gram’s method are commonly classified as:

A

Gram-positive and gram-negative

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7
Q

Others that are not stained by crystal violet are referred to as

A

Gram-negative

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8
Q

is based on the ability of bacteria cell wall to retaining the crystal violet dye during solvent treatment.

A

Gram staining

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9
Q

The cell walls for Gram-positive microorganisms have a _____________ and _____________ than gram negative

A

Higher peptidoglycan and lower lipids

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10
Q

What does gram staining are stained by the crystal violet.

A

Bacteria cell wall

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11
Q

is subsequently added as a mordant to form the crystal violet-iodine complex so that the dye cannot be removed easilv.

A

Gram’s iodine

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12
Q

In gram iodine This step is commonly referred

A

Fixing the dyes

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13
Q

In contrast, the solvent dehydrates the thicker Gram-positive cell walls. closing the pores as the cell wall shrinks during dehydration.

A

Gram decolorizer

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14
Q

a counterstain is applied to the smear to give decolorized gram-negative bacteria a pink color.

A

Safranin red or basic fuchsin

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15
Q

Some laboratories use ___________ as a counterstain instead.

A

safranin

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16
Q

many Gram-negative bacteria more intensely than does safranin, making them_easier to see.

A

Basic fuchsin stain

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17
Q

Some bacteria which are poorly stained by safranin, such as

A

Legionella spp. and haemophilus

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18
Q

Equipments of gram staining:

A

Bunsen burner/alcohol lamp
Microscope slide
Water

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19
Q

Reagents used for gram staining

A

Crystal violet
Gram’s iodine
Acetone alcohol
Safranin red

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20
Q

How many mins/sec are needed in Crystal violet

A

1 min

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21
Q

How many mins/sec needed in gram’s iodine

A

2 mins

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22
Q

How many mins/sec are needed for acetone alcohol

A

30 seconds

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23
Q

How many mins/sec are needed for safranin red

A

1min

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24
Q

In slide smear: Spread the culture with an inoculation loop to an even thin film over a circle of

A

1.5 cm in diameter

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25
If staining a clinical specimen, smear layer are needs to be
Very thin layer
26
In gram staining what kind of tool that you use to spread a culture
wooden stick
27
After you stain what do you use to Pour off the stain and gently rinse the excess stain with a stream of water from a
Faucet or bottle of water
28
What do you use to remove/blot the excess water after streaming it through the water
Tissue or paper towel
29
Acid-fastness is the characteristic feature of what genus
Mycobacteria
30
It pertains to the ability of the bacterial cell wall to withstand strong acid decolorizers due to the presence of primarily long chain waxy mycolic acids
Acid-fastness
31
are easily decolorized wit acid alcohoL thereby taking up the counterstain.
Non-acid fast organism
32
Acid-rastness can also be seen (although only partial/weak) on certain bacteria namely,
Nocardia spp. and rhodococcus
33
are hard to stain, they require heat and or solvents to drive the stain into the cell wall, but once stained, they will be hard to decolorize
Acid-fast organism
34
PATIENT PREPARATION: for sputum collection
1. Gargle luke warm water (distilled water only) 2. Do not gargle using mouth wash 3. Do not brush your teeth 4. Do not drink 5. Do not eat
35
SAMPLE COLLECTION: what is the best time is the preferred specimen for AFB staining
Early morning sputum
36
In sample collection If the patient is ambulatory, use
Aerosol-induced collection or hypertonic saline
37
Collection of sputum at least
1teaspoonful or 5-10 mL for direct sputum smear microscopy
38
For Xpert MTB/RIF, sputum samples should not be less than
1 mL
39
is the other commonlv used stain for light-microscopic examination of bacteria.
Acid-fast staining
40
is specifically designed for a subset of bacteria whose cell walls contain long-chain fatty (mycolic) acids.
Acid-fast stain
41
render the cells resistant to decolorization, even with acid alcohol decolorizers.
Mycolic acid
42
In AFB STAIN Athese bacteria are referred to as
Being acid-fast
43
are the most commonlv encountered acid-fast bacteria
Mycobacteria
44
typified by _________________ the etiologic agent of tuberculosis.
Mycobacterium tuberculosis
45
The Acid-fast stained smear is read at what magnification
1000x magnification
46
debris, and other host cells stain depending on the counterstain
Non-acid fast organism
47
has been used as a counterstain, the background, non-acid fast organisms. debris, and other host cells will be stained green.
Malachite green
48
nas been used as a counterstain. the background. non-acid fast organisms, debris, and other host Cell will be stained blue
Methylene blue
49
The classic acid-fast staining method, requires heat to allow the primary stain (carbol fuchsin) ti enter the wax-containing cell wall.
Ziehl-neelsen
50
What is the mordant of ziehl-neelsen
Heat
51
A modification of this procedure, does not require the use of heat or boiling water, minimizing safety concerns during the procedure.
Kinyoun acid fast method
52
This modification is referred to as the "cold" method.
Kinyoun acid-fast method
53
What is the mordant of kinyoun acid-fast method
Phenol
54
Reagents used for acid-fast staining
- carbol fuchsin - acid alcohol - methylene blue
55
Equipments used for AFB staining
- bunsen burner/alchohol lamp - alcohol cleaned microscope slide - applicator stick - tripod - aluminum foil - water
56
What is the cm that is used in acid fast ziehl- neelsen
2.5 cm length by 1.5 cm width or oval translucent smear
57
How long to air dry the acid-fast smear
15 minutes
58
How many minutes thus carbol fuchsin and oow flame steam (heat) needed
5 minutes
59
How many mins/sec are needed in acid alcohol for acid-fast stain
30 seconds
60
How many mins/secs are needed for methylene blue in acid fast staining
1 minute
61
Read the whole slide from left to right. This is equivalent to
150 fields
62
Go down 1 field and read it from right to left. This is equivalent to another 150 fields for a
300 fields in total
63
Acid-fast organisms, Mycobacterium spp., will appear
Red
64
Non Acid-fast organisms will appear
Blue
65
WHO scale in ziehl-neelsen what interpretation is No AFB observed in 300 oil immersion field
0
66
Who scale in ziehl-nelseen what interpretation 1-9 AFB/100 OIF
+n
67
Who scale in ziehl-neelsen what interpretation 10-99 AFB/ 100 OIF
1+
68
Who scale in ziehl-neelsen what interpretation is 1-10 AFB/ OIF in at least 50 fields
2+
69
Who scale in ziehl-neelsen what interpretation is >(GREATER THAN)10 AFB/OIF in at least 20 fields
3+
70
What is the principle of gram stining
the ability of the bacterial cell wall to retain the crystal violet dye during staining
71
What is the principle of AFB staining
is used to distinguish acid-fast bacteria from non-acid-fast bacteria.

Bacte Quizes (16 decks)

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