DIFFERENTIAL STAINS

Question 1

Most critical step in Gram staining

Answer 1

Decolorization

Question 2

Gram stain:
Primary stain ________________
Mordant _________________
Decolorizer ____________________
Counterstain____________

Answer 2

Primary stain - CRYSTAL VIOLET
Mordant - IODINE
Decolorizer - 95% ETHYL ALCOHOL
Counterstain - SAFRANIN

Question 3

All cocci are gram (+) except:

Answer 3

NVB - Neisseria, Veillonella, Branhamella

Question 4

All bacilli are gram (-) except:

Answer 4

MCCBELL - Mycobaceterium, Clostridium, Corynebacterium, Bacillus, Erysipelothrix, Listeria, and Lactobacillus

Question 5

Crystal violet with ammonium oxalate

Answer 5

Hucker’s Modification

Question 6

Acid Fast Stain General Rule:

Answer 6

All bacteria are non-acid fast except MYCOBACTERIA group.

Question 7

Slightly acid fast

Answer 7

Nocardia asteroides

Question 8

The cell wall of MYCOBACTERIA group. contains

Answer 8

Mycolic acid

Question 9

Ideal sputum:

Answer 9

• cheesy-like
• Yellowish/greenish
• Mucopurulent
• Presence of blood

Question 10

Unable to produce phlegm

Answer 10

Induced sputum

Question 11

Ziehl Neelsen:

Primary stain _______________
Mordant _______________
Decolorizer _______________
Secondary stain _______________
Color of AFO _______________
Color of NAFO _______________

Answer 11

Primary stain : Carbol fuchsin
Mordant : STEAM/HEAT
Decolorizer : 3% ACID ALCOHOL
Secondary stain : METHYLENE BLUE
Color of AFO : RED
Color of NAFO : BLUE

Question 12

Size of AFB smear

Answer 12

2x3 cm

Question 13

Best method for Direct Sputum Smear Microscopy

Answer 13

Ziehl Neelsen

Question 14

Best stain for AFO in tissues

Answer 14

Kinyoun method

Question 15

Kinyoun Method:

Primary stain _______________
Mordant _______________
Decolorizer _______________
Secondary stain _______________
Color of AFO _______________
Color of NAFO _______________

Answer 15

Primary stain : Carbol fuchsin
Mordant : WETTING AGENT/TERGITOL
Decolorizer : HCL + ETHANOL
Counterstain : MALACHITE GREEN
Color of AFO : RED
Color of NAFO : GREEN

Question 16

Differentiates M. smegmatis from M. tuberculosis

Answer 16

Pappenheim stain

Question 17

Differentiates M. tuberculosis from M. leprae

Answer 17

Baumgarten’s method

Question 18

AKA Auramine-Rhodamine fluorochrome staining

Answer 18

Truant Stain

Question 19

Truant Stain:

Decolorizer : _______________
Counterstain : _______________

Answer 19

Decolorizer : 0.5% acid alcohol
Counterstain : 0.5% potassium permanganate

Question 20

AKA quenching agent

Answer 20

0.5% potassium permanganate

Question 21

10% more sensitive than ZN
Fluorescent staining method

Answer 21

Truant Stain

Question 22

Cold method

Answer 22

Kinyoun method

Question 23

Hot method

Answer 23

Ziehl Neelsen