MICROBIOLOGY - Stains, Cultures, Sterilisation

Question 1

What stain is used to identify fungi? (6)

Answer 1

1. Gomori-methamine silver - stains black
2. Grocott hexamine silver - fungi + acanthomoeba stains black
3. Periodic acid schiff - stains purple/magenta
4. Calcufluor - stains white
5. haematoxylin and eosin stains pink
6. KOH

Question 2

What stain is used to identify calcium (2)

Answer 2

Alizarin Red
Von Kossa

Question 3

What are the stains involved in dystrophies?
1) Reis-Bucklers
2) Granular Dystrophy
3) Macular dystrophy of cornea

Answer 3

1) Masson Trichome stains new collagen blue
2) Masson Trichome stains hyaline material red
3) Alician blue stains mucopolysaccharides

Question 4

What do MacConkey agar and McCoy agar grow?

Answer 4

1. MacConkey agar - lactose fermenting G-ves
2. McCoy agar - chlamydia (obligate intracellular bacteria)

Question 5

What does Thayer-Martin medium and Thioglycate agar grow?

Answer 5

1. Thayter martin - G-ve cocci (Neisseria)
2. Thioglycate: aerobes on surface, anaerobes inside

Question 6

What does Lowenstein-Jenson medium grow?

Answer 6

Mycobacteria tuberculosis
Nocardia

Question 7

What does chocolate agar, blood agar and cooked meat broth medium grow?

Answer 7

1. Chocolate - haemophilus, neisseria,
2. Blood agar - all bacteria except H, N
3. Cooked meat broth - anaerobes and fastiduous organisms

Question 8

What does non-nutrient agar with E.coli grow and Sabouraud agar grow?

Answer 8

1. Non-nutrient - Acanthomaeba
2. Sabouraud - Fungi

Question 9

What is the gram staining process?
Whats the difference between gram +ve and gram -ve?

Answer 9

1. Crystal violet blue stain
2. Iodine stain
3. Decolourisation with acetone
4. Counterstain with carbol fuschin/safrain

Gram +ve organism have polyasaccaride cell well which does not decolourise well so stays crystal blue

Gram -ve organise are susceptible to decolourisation with acetone so stains red with counterstain

Question 10

What is the process of sterilisation?

Question 11

Which reaction allows for the distinction of different types of clostridum perfringens?

Answer 11

Nagler reaction

Question 12

What culture media is used for acanthamoeba?

Answer 12

Non-nutrient agar with E Coli

Question 13

What staining is used to determine presence of intra-cytoplasmic inclusion bodies? What disease is this most commonly associated with this?

Answer 13

Giemsa stain (also stains fungi)
Intra-cytoplasmic inclusion bodies are commonly associated with chlamydia

Question 14

Which culture medium is used for TB?

Answer 14

Lownestein-Jensen

Question 15

Which culture medium is used for gonococcus?

Answer 15

Theyer-Martin

Question 16

Which culture medium is used for fungus?

Answer 16

Sabouraud’s agar

Question 17

Which culture is best for anaerobes?

Answer 17

Blood agar (not haemophilus, neisseria)

Question 18

What are the processes in Disinfection? Which examples?

Answer 18

1. UV radiation
2. Pasteurisation - steam generated at 80 degrees at half an atmosphere of pressure - kills vegetative organisms but not spores

examples
1. Chlorhexidine
2. ethyl alcohol with povidone-iodine

Question 19

Whats involved in the process of sterilisation?

Answer 19

1. Gamma radiation
2. Dry heat - temp of 160 degrees for several hours
3. Moist heat - 134 degrees for 3 minutes / 121 degrees for 120 minutes
4. Ethylene oxide

Question 20

Mucicarcmine stains what colour and for what lesion?

Answer 20

Stains pink for mucous secreting adenocarcinoma

Question 21

Luxol fat blue stains what substance?

What does Bodian stain and what colour?

Answer 21

Luxol blue: Myelin
Bodian: Stains nerve fibres - stains black.

Question 22

Loeffler’s culture media stains what pathogen?

Answer 22

Cornyebacteria

Question 23

What does Von Kossa stain?

Answer 23

Stains calcium black - for band keratopathy.

Question 24

Moraxella is grown on which culture medium?

Answer 24

Blood agar in 5% carbon dioxide

Question 25

What does Movat’s pentachrome stain?

Answer 25

Elastic tissue black.

Question 26

Drusen are associated with which positive stain?

Answer 26

PAS.

Question 27

What does haematoxylin stain and what colour?

Answer 27

Stains nucleic acids BLUE.

Question 28

Which conditions are associated with keratoconus? (5)

Answer 28

1. Vernal keratoconjunctivitis
2. Retinitis Pigmentosa
3. Retinopathy of Prematurity
4. Down’s Syndrome
5. Marfan’s Syndrome

Question 29

What does Bodian stain and what colour?

Answer 29

Stains nerve fibres - stains black.

Question 30

Recurrent chalazia and unilateral blepharitis is associated with which cancer? Which stain is used?

Answer 30

Sebaceous cell carcinoma - commonly upper eyelid.

Oil Red O / Sudan black stain is used.

Question 31

What is used to prepare tachyzoites and bradyzoites for viewing?

Answer 31

Toxoplasmosis - Paraffin section is used.