Stains and Agars

Question 1

Which bacteria cannot be gram stained? (11)

Answer 1

Treponema, Leptospira - too small

Mycobacteria - cell wall w/ lipid content

Myoplasma, ureaplasma - no cell wall

Legionella, Rickettsia, Chlamydia, Bartonella, Anaplasma, Ehrlichia - primarily intracellular

**Chlamydia also has dec muramic acid so less peptidoglycans (“no mermaids”)

Question 2

Giemsa Stain (5)

Answer 2

GEMS

Chlamydia

Borrelia

Ricketssia

Trypanosomes

Plasmodium

Question 3

PAS Stain

Answer 3

Stains glycogen / mucus

Whipple Disease

Question 4

Ziehl Neelsen stain

Answer 4

Fuchsin (FUSCIA guns)

Mycobacterium, Nocardia

Cryptosporidium oocytes

Question 5

India Ink

Answer 5

Cryptococcus neoformans

can also use mucicarmine to stain thick capsule red - red sarcophagus

background is dark

Question 6

Silver Stain

Answer 6

PJP (paddles)

Coccidoides

H pylori

Legionella

Question 7

Chocolate Agar

Answer 7

H flu (halloween sketch)

Contains Factor V and Factor X (5 and 10 cent candies)

NAD+ / hemaTEN

Question 8

Thayer - Martin

Answer 8

Star of Noir series (Neisseria gonorrhea and mening)

-Vancomycin, Nystatin, Trimethoprim, Colistin

Question 9

Which 2 stains can be used for Bordetella pertussis ?

Answer 9

Bordet - Gengou (potato extract)

or Regan-Lowe Stains (blood, charcoal, abx)

Question 10

Which 2 stains can be used for C diphtheria?

Answer 10

Tellurite

Loffler

“LAUGH if you TELL RITE joke”

Question 11

Lowenstein - Jensen

Answer 11

Tb 2-6 wks

Question 12

Eaton Agar

Answer 12

Myoplasma pneumoniae

Requires cholesterol (“eat” fatty foods)

Question 13

MacConkey Agar

Answer 13

Fermentation –> acid –> pink colonies ( E coli)

Question 14

EMB Agar

Answer 14

Eosin - methylene blue

E coli turns this green (green coasters)

Question 15

How do you stain for Legionella?

Answer 15

Charcoal yeast extract agar w/ cysteine and iron buffer

Coal - powered SS Cysteine

Question 16

Sabouraud Agar

Answer 16

Fungi