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Bacte Quizes > Laboratory Gram Stain And Afb Stain > Flashcards

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
Q

If staining a clinical specimen, smear layer are needs to be

A

Very thin layer

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26
Q

In gram staining what kind of tool that you use to spread a culture

A

wooden stick

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27
Q

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

A

Faucet or bottle of water

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28
Q

What do you use to remove/blot the excess water after streaming it through the water

A

Tissue or paper towel

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29
Q

Acid-fastness is the characteristic
feature of what genus

A

Mycobacteria

30
Q

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

A

Acid-fastness

31
Q

are easily decolorized wit acid alcohoL thereby taking up the counterstain.

A

Non-acid fast organism

32
Q

Acid-rastness can also be seen
(although only partial/weak) on certain bacteria namely,

A

Nocardia spp. and rhodococcus

33
Q

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

A

Acid-fast organism

34
Q

PATIENT PREPARATION: for sputum collection

A
  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
Q

SAMPLE COLLECTION: what is the best time is the preferred specimen for AFB staining

A

Early morning sputum

36
Q

In sample collection If the patient is ambulatory, use

A

Aerosol-induced collection or hypertonic saline

37
Q

Collection of sputum at least

A

1teaspoonful or 5-10 mL for direct sputum smear microscopy

38
Q

For Xpert MTB/RIF, sputum samples should not be less than

A

1 mL

39
Q

is the other commonlv used stain for
light-microscopic examination of bacteria.

A

Acid-fast staining

40
Q

is specifically designed for a subset of bacteria whose cell walls contain long-chain fatty (mycolic) acids.

A

Acid-fast stain

41
Q

render the cells resistant to decolorization, even with acid alcohol decolorizers.

A

Mycolic acid

42
Q

In AFB STAIN Athese bacteria are referred to as

A

Being acid-fast

43
Q

are the most commonlv encountered acid-fast bacteria

A

Mycobacteria

44
Q

typified by _________________ the etiologic agent of tuberculosis.

A

Mycobacterium tuberculosis

45
Q

The Acid-fast stained smear is read at what magnification

A

1000x magnification

46
Q

debris, and other host cells stain depending on the counterstain

A

Non-acid fast organism

47
Q

has been used as a counterstain, the background, non-acid fast organisms. debris, and other host cells will be stained green.

A

Malachite green

48
Q

nas been used as a
counterstain. the background. non-acid fast organisms, debris, and other host
Cell will be stained blue

A

Methylene blue

49
Q

The classic acid-fast staining method, requires heat to allow the primary stain (carbol fuchsin) ti enter the wax-containing cell wall.

A

Ziehl-neelsen

50
Q

What is the mordant of ziehl-neelsen

A

Heat

51
Q

A modification of this procedure, does not require the use of heat or boiling water, minimizing safety concerns during the procedure.

A

Kinyoun acid fast method

52
Q

This modification is referred to as the “cold” method.

A

Kinyoun acid-fast method

53
Q

What is the mordant of kinyoun acid-fast method

A

Phenol

54
Q

Reagents used for acid-fast staining

A
  • carbol fuchsin
  • acid alcohol
  • methylene blue
55
Q

Equipments used for AFB staining

A
  • bunsen burner/alchohol lamp
  • alcohol cleaned microscope slide
  • applicator stick
  • tripod
  • aluminum foil
  • water
56
Q

What is the cm that is used in acid fast ziehl- neelsen

A

2.5 cm length by 1.5 cm width or oval translucent smear

57
Q

How long to air dry the acid-fast smear

A

15 minutes

58
Q

How many minutes thus carbol fuchsin and oow flame steam (heat) needed

A

5 minutes

59
Q

How many mins/sec are needed in acid alcohol for acid-fast stain

A

30 seconds

60
Q

How many mins/secs are needed for methylene blue in acid fast staining

A

1 minute

61
Q

Read the whole slide from left to right.
This is equivalent to

A

150 fields

62
Q

Go down 1 field and read it from right to
left. This is equivalent to another 150
fields for a

A

300 fields in total

63
Q

Acid-fast organisms, Mycobacterium spp., will appear

A

Red

64
Q

Non Acid-fast organisms will appear

A

Blue

65
Q

WHO scale in ziehl-neelsen what interpretation is No AFB observed in 300 oil immersion field

A

0

66
Q

Who scale in ziehl-nelseen what interpretation 1-9 AFB/100 OIF

A

+n

67
Q

Who scale in ziehl-neelsen what interpretation 10-99 AFB/ 100 OIF

A

1+

68
Q

Who scale in ziehl-neelsen what interpretation is 1-10 AFB/ OIF in at least 50 fields

A

2+

69
Q

Who scale in ziehl-neelsen what interpretation is >(GREATER THAN)10 AFB/OIF in at least 20 fields

A

3+

70
Q

What is the principle of gram stining

A

the ability of the bacterial cell wall to retain the crystal violet dye during staining

71
Q

What is the principle of AFB staining

A

is used to distinguish acid-fast bacteria from non-acid-fast bacteria.

Bacte Quizes (16 decks)

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