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Clinical Bacteriology (Prelim) > (Laboratory) Gram Staining and Acid-fast Staining > Flashcards

(Laboratory) Gram Staining and Acid-fast Staining Flashcards

1
Q

Gram Stain is named after the Danish Bacteriologist who originally devised it in 1882 (published 1884), _____

A

Hans Christian Gram

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2
Q

Gram Stain is named after the Danish bacteriologist who originally devised it in _____ (published _____), Hans Christian Gram

A

1882
1884

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3
Q

The primary stain of the Gram’s method

A

Crystal Violet

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4
Q

Crystal Violet is sometimes substituted with _____

A

Methylene Blue

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5
Q

Gram-positive organisms appear _____ under a microscope

A

Violet/Blue

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6
Q

Gram-negative organisms appear _____ under a microscope

A

Pink/Red

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7
Q

Principle of Gram Staining

A

Gram Staining is based on the ability of bacteria cell walls to retain the crystal violet dye during solvent treatment.

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8
Q

Mordant in Gram Staining Method

A

Gram’s Iodine

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9
Q

Reagent used in Gram Staining to enhance the staining capability of the primary dye

A

Gram’s Iodine

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10
Q

Acts as decolorizer; removes the primary dye in Gram Staining

A

Acetone Alcohol

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11
Q

Secondary dye/Counterstain; to give stain on bacteria that has been wash off upon applying decolorizer in Gram Staining

A

Safranin

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12
Q

_____ stains many Gram-negative bacteria more intensely than does Safranin, making them easier to see.

A

Basic Fuchsin

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13
Q

Some bacteria which are poorly stained by Safranin, such as _____ and _____ and some anaerobic bacteria, are readily stained by Basic Fuchsin, but not Safranin.

A

Haemophilus spp.
Legionella spp.

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14
Q

Based on the Lecture Video, list down the Equipment used in Gram Staining:

A

Bunsen Burner/Alcohol Lamp
Microscope Slide
Water

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15
Q

Based on the Lecture Video, list down the Reagents used in Gram Staining (on chronological order):

A

Crystal Violet
Gram’s Iodine Solution
Acetone or Ethanol
Basic Fuchsin Solution

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16
Q

In Gram Staining, we smear a very thin layer onto the slide, using _____

A

Wooden Stick

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17
Q

True or False

We use cotton swab in applying or layering the specimen onto the slide in Gram Staining.

A

False

We do not use cotton swab as the cotton fibers may appear as artifacts.

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18
Q

In Gram Staining, spread the culture with an inoculation loop to an even thin film over a circle of _____ in diameter

A

1.5 cm

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19
Q

Time for Crystal Violet application in Gram Staining

A

60 Seconds or 1 Minute

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20
Q

Time for Gram’s Iodine application in Gram Staining

A

120 Seconds or 2 Minutes

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21
Q

Time for Acid Alcohol application in Gram Staining

A

30 Seconds

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22
Q

Time for Safranin application in Gram Staining

A

60 Seconds or 1 Minute

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23
Q

The characteristic feature of the genus Mycobacteria.

A

Acid-fastness

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24
Q

Aside from Mycobacteria, acid-fastness can also be seen (although only partial/weak) on certain bacteria namely:

A

Nocardia spp.
Gordona
Rhodococcus
Tsukamurella
Legionella micdadei

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25
A type of lipid and repels water
Mycolic Acid
26
Preferred to do in Patient Preparation for AFB Stain
Gargle with lukewarm distilled water only
27
Preferred not to do in Patient Preparation for AFB Stain
- Do not gargle with mouthwash - Brushing your teeth is prohibited - Do not eat - Do not drink
28
Preferred specimen for AFB Staining
Early morning sputum
29
In AFB Staining, if the patient is ambulatory, use _____
Aerosol-induced collection
30
We only do the aerosol-induced collection if the patient is _____
Ambulatory
31
Collect at least _____ or _____ for DSSM
1 Teaspoonful or 5-10 mL
32
Collect at least 1 teaspoonful or 5-10 mL for _____
DSSM (Direct Sputum Smear Microscopy)
33
For Xpert MTB/RIF, sputum sample should _____
Not be less than one (1) mL
34
For _____, sputum sample should not be less than one (1) mL
Xpert MTB/RIF
35
The etiologic agent of tuberculosis
Mycobacterium Tuberculosis
36
The most commonly encountered acid-fast bacteria, typified by Mycobacterium tuberculosis, the etiologic agent of tuberculosis.
Mycobacteria
37
The Acid-fast stained smear is red at _____
1000x magnification
38
If Malachite Green has been used as a counter stain, the background, non-acid fast organisms, debris, and other host cells will be stained _____
Green
39
If _____ has been used as a counter stain, the background, non-acid fast organisms, debris, and other host cells will be stained green.
Malachite Green
40
If Methylene Blue has been used as a counter stain, the background, non-acid fast organisms, debris, and other host cells will be stained _____
Blue
41
If _____ has been used as a counter stain, the background, non-acid fast organisms, debris, and other host cells will be stained blue
Methylene Blue
42
Also known as "Hot Method" in AFB Staining
Ziehl-Neelsen Method
43
A method in AFB Stain that uses heat as a mordant
Ziehl-Neelsen Method
44
Ziehl-Neelsen Method uses _____ as a mordant
Heat
45
Ziehl-Neelsen Method uses heat as a _____
Mordant
46
Also known as the "Cold Method" in AFB Stain
Kinyoun Acid-fast Method
47
What is added in the primary stain for Kinyoun Acid-fast Method?
Phenol
48
In the Lecture Video, list down the Reagents used for AFB Staining (Ziehl-Neelsen Method) in chronological order:
Aqueous Carbol Fuchsin Acetone Alcohol Methylene Blue
49
In the Lecture Video, list down the Equipment used for AFB Staining (Ziehl-Neelsen Method):
Bunsen Burner/Alcohol Lamp Alcohol-cleaned Microscope Slide Applicator Stick Tripod Aluminum Foil Water
50
Preferred size of sputum specimen in smear
Thumb-shaped Size
51
Time for applying Carbol Fuchsin Solution in AFB Stain
5 minutes with heating in between
52
Time for applying Acid Alcohol in AFB Stain
30 Seconds
53
Time for applying Methylene Blue in AFB Stain
60 Seconds or 1 Minute
54
In AFB reading interpretation, reading the slide from left to right is equivalent to _____
150 Fields
55
In AFB reading interpretation, reading the slide from left to right, and the going down to read the slide from right to left is equivalent to _____
300 Fields
56
Acid-fast organisms appear _____ under a microscope
Red Color
57
Non-acid-fast organisms appear _____ under a microscope
Blue Color
58
Causes of False-positive Acid-fast Smear:
1. Changes in the cell wall. 2. Insufficient decolorization. 3. Laboratory contamination. 4. Delayed processing and overgrowth of other bacteria.
59
Causes of False-negative Acid-fast Smear:
1. Overzealous decontamination. 2. Loss from concentration techniques. 3. Organism obscured by a very thick smear. 4. Over decolorization. 5. Poor counterstaining. 6. Lack observer proficiency in reading sputum smears.
60
No AFB observed in 300 Oil Immersion Field is equivalent to _____ in WHO Scale for AFB
0
61
1-9 AFB/100 OIF is equivalent to _____ in WHO Scale for AFB
+n
62
10-99 AFB/100 OIF is equivalent to _____ in WHO Scale for AFB
1+
63
1-10 AFB/OIF in at least 50 fields is equivalent to _____ in WHO Scale for AFB
2+
64
>10 AFB/OIF in at least 20 fields is equivalent to _____ in WHO Scale for AFB
3+
65
A 0 in WHO Scale for AFB means _____
No AFB observed in 300 Oil Immersion Field
66
An n+ in WHO Scale for AFB means _____
1-9 AFB/100 OIF
67
A 1+ in WHO Scale for AFB means _____
10-99 AFB/100 OIF
68
A 2+ in WHO Scale for AFB means _____
1-10 AFB/OIF in at least 50 fields
69
Aside from Mycobacteria, two other Gram-positive genera, namely _____ and _____, may stain Acid-fast by modified method.
Nocardia Rhodococcus
70
A 3+ in WHO Scale for AFB means
>10 AFB/OIF in at least 20 fields

Clinical Bacteriology (Prelim) (17 decks)

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