Microbiological Stains (Wk 13)

Question 1

Why is the Wade-Fite stain necessary when ZN exists

Answer 1

Demonstrates M. leprae which is acid-fast but NOT acid/alcohol-fast

Question 2

Proteoglycan layer of bacterial cell walls is known as?

Answer 2

Peptidoglycan

Question 3

How to identify cytomegalovirus?

Answer 3

CMV-infected cells have large nuclei w/ basophilic inclusions

Question 4

What is used for prions decontamination

Answer 4

1M NaOH

Question 5

What is used to for differentiation in ZN stain?

Answer 5

Acid/alcohol

Question 6

2 stains that can demonstrate hepatitis

Answer 6

Shikata’s orcein

Phloxine tartrazine

Question 7

Primary stain in Ziehl-Neelson?

Answer 7

Carbol fuchsin

Question 8

Aside from Mycobacteria, ZN can also stain what 2 types of bacteria?

Answer 8

Actinomyces and Nocardia

Question 9

3 components of carbol fuchsin?

Answer 9

Basic fuchsin
Alcohol
Phenol

Question 10

Type of silver used in Grocott’s

Answer 10

Methenamine silver

Question 11

2 specialized argyrophil methods to demonstrate Spirochetes

Answer 11

Warthin-Starry

Dieterle’s

Question 12

Grocott’s is an ______ reaction (type of silver rxn) and is performed at ___degC

Answer 12

argentaffin

60degC

Question 13

Gram positives have a thicker ________ layer than Gram negatives

Answer 13

peptidogylcan

Question 14

Demonstrates hepatitis, somewhat specific for HepB surface antigen

Answer 14

Shikata’s orcein

Question 15

This component in Mycobacteria help them retain ZN stain, but is also responsible for preventing them from staining with Gram’s

Answer 15

mycolic acid

Question 16

2 stains that will demonstrate Helicobacter

Answer 16

Giemsa

Dieterle’s

Question 17

2 components of Twort’s (counterstain for Gram’s)

Answer 17

Safranin (cationic), stains Gram neg bacteria

Fast green (anionic), stains tissue

Question 18

M. leprae is localized to _______

Answer 18

nerves

Question 19

Grocott - what is used to remove excess chromic acid

Answer 19

Sodium bisulfite

Question 20

What part of fungi get stained by the Grocott methenamine silver method

Answer 20

carbohydrates in the fungal capsule

Question 21

What are the 2 cationic dyes in Gram’s

Answer 21

Crystal violet, safranin

Question 22

Used to correct pH in Grocott’s

Answer 22

Borax

Question 23

Counterstain in Grocott’s

Answer 23

Fast green

Question 24

Used to diagnose herpes virus

Answer 24

Tzanck smear

Question 25

Tissues are deparaffinized with __________ for the Wade-Fite stain

Answer 25

peanut oil/xylene

Question 26

Why is heat not required in ZN

Answer 26

Phenol drives stain into the bacteria

Question 27

Typical counterstain for ZN?

Answer 27

Methylene blue

Question 28

This component of the ZN stain is responsible for driving the primary stain into the bacteria

Answer 28

phenol

Question 29

Spirochetes stain: _________ is used to reduce silver to a visible deposit

Answer 29

hydroquinone

Question 30

Tzanck smear for herpes is stained with?

Answer 30

Giemsa

Question 31

What is the tissue stain in Gram’s counterstain

Answer 31

Fast green (anionic)

Question 32

Reagent used for differentiation in Wade-Fite?

Answer 32

Sulfuric acid

Question 33

Oxidizing agent in Grocott and why it’s used

Answer 33

Chromic acid - very strong oxidizing agent

OVER-oxidizes glycogen + neutral glycoproteins