The Mess That Is Micro - I -Stains

Question 0

N. gonorrhoeae, N. meningitidis

Answer 0

Thayer-martin or VPN media.
V- vancomycin
P - polymyxin
N - nystatin

Remember: Use thayer-martin or VPN media (from song).
Nice men in Vans Think Polly is Nice.

Question 1

H. Influenzae culture requirements

Answer 1

Chocolate agar or sheep’s blood agar with factors V (NAD+) and X (hemantin - an iron-containing porphyrin). You can also streak agar with staph aureus and it will produce the NAD+ and hemantin for the H. Flu

Remember- the kid had flu so his mom went to the five and dime store to buy him chocolate.

Question 2

Bordetella pertussis media

Answer 2

Bordet-Gengou (potato) agar

Remember: Bordet –> Bordetella
I’m bored of potatoes!

Question 3

C. diptheriae

Answer 3

Tellurite agar, Loffler media

Remember: dip the teller in agar and LAFF at him!

Question 4

M. Tuberculosis

Answer 4

Lowenstein-Jensen agar

Remember:
Jen lay Low in the Tub, hiding from her enemies.

Question 5

M. Pneumoniae culture requirements

Answer 5

Eaton agar, requires cholesterol.

Remember: Lambert-eaton myasthenia is associated with lung ailments so pneumonia
OR: if you have pneumonia, gotta eat, gotta get your cholesterol.

Question 6

Lactose fermenting enterics, culture requirements

Answer 6

MacConkey agar (fermentation produces acid, turning the colony pink) -

E coli is also grown on eosin-methylene blue (EMB) agar as colonies with a green metallic sheen. Lactose fermenters grow as purple and black colonies on this agar.

Question 7

Legionella

Answer 7

Charcoal yeast extract agar buffered with cysteine and iron

Remember: the legion lost because the sistine chapel lit on fire (charcoal) and had more iron weapons. And more yeast to bake bread.

Question 8

Fungi culture medium

Answer 8

Sabourad agar

Remember: Sab’s a fun guy!

Question 9

Giemsa stain - what does it stain?

Answer 9

Remember: plastered clams try to borrow Rick’s gems.

Plasmodia, chlamydia, trypanosomes, borrelia, rickettsia, giemsa stain!

Question 10

PAS (periodic acid-schiff stain)

Answer 10

Stains glycogen, mucopolysaccharides, used to diagnose Whipple disease - Tropheryma whipplei

Remember: Pass the can of whipped cream

Question 11

Ziehl-Neelsen

Answer 11

Acid-fast organisms - Nocardia, mycobacterium

I Kneel in the Aisle on the Fuschia Carpet Assisting My Coworker with No heartbeat.
Ziehl-Neelsen (Carbol-fuchsin), acid-fast (assisting), mycobacteria, nocardia (no heartbeat)

Question 12

India ink

Answer 12

Cryptococcus

Question 13

Silver stain

Answer 13

Fungi (pneumocystis), legionella, helicobacter pylori

Remember: silver legions have fun in the sun

Question 14

Which bacteria do not gram stain well?

Answer 14

These microbes may lack real color
Treponema (too thin), mycobacteria (high lipid content in cell wall detected by carbolfuschin in acid fast), mycoplasma (no cell wall), legionella (intracellular), rickettsia (intracellular) chlamydia (intracellular)

Question 15

How to gram stain?

Answer 15

1. Primary stain - crystal violet is applied.
2. Iodide binds to crystal violet and traps it in the cell
3. Rapid decolorization with ethanol or acetone. Gram negatives lose outer polysaccharide membrane and crystal violet washes out.
4. Counterstain with safranin so the cell still has some color.

Ultimately, gram positives are purple and gram negatives are pink!

Question 16

What bacteria gram stain poorly (gram positive but are unreliable)?

Answer 16

Arthur Acts Courteous and Proper behind My Back

Arthobacter
Actinomyces
Corynebacterium
Propionibacterium
Mycobacterium

Question 17

Hippurate test

Answer 17

Positive in group B strep. Ability to hydrolyze sodium hippurate.

Think: group b strep is found in babies. Babies have stuffed hippo toys.