Bacteria Staining

Question 1

Bugs that don’t gram stain well

Answer 1

Rickettsia, Legionella, Chlamydia - intracellular; Treponema - too thin to be visualized; Mycobacteria - high lipid content in cell wall - need acid-fast stain; Mycoplasma - no cell wall (contains sterols)

Question 2

Giemsa

Answer 2

Chlamydia, Borrelia, Rickettsiae, Trypanosomes, Plasmodium; (Certain Bugs Really Try my Patience)

Question 3

PAS (periodic acid-Schiff)

Answer 3

Stains glycogen; Diagnosis of Whipple’s disease (Tropheryma whipplei)

Question 4

Ziehl-Neelson (carbol fuschin)

Answer 4

Acid-fast - IDs mycolic acid in cell wall; Nocardia, Mycobacterium

Question 5

India ink

Answer 5

Cryptococcus neoformans

Question 6

Silver Stain

Answer 6

Legionella, H. Pylori, PCP/PJP, Fungi (i.e. pneumocystis)

Question 7

Chocolate agar with factors V (NAD+) and X (hematin)

Answer 7

H. influenzae

Question 8

Thayer-Martin (VPN) media - Vancomycin, Polymyxin, Nystatin

Answer 8

Neisseria (men. and gon.); V inhibits gram pos, P inhibits gram neg (except neisseria), N inhibits fungi

Question 9

Bordet-Gengou (potato agar)

Answer 9

B. pertussis

Question 10

Tellurite plate, Loffler’s media

Answer 10

C. diphtheria

Black colonies on cystine-tellurite agar

Question 11

Lowenstein-Jensen agar

Answer 11

M. tuberculosis

Question 12

Eaton’s agar

Answer 12

M. pneumoniae

Question 13

MacConkey’s agar

Answer 13

Lactose-fermenting enterics are positive; Agar made up of Bile salts and Crystal violet (which inhibit gram positives) and also Lactose and Neutral red. So 4 things overall

Question 14

Eosin-methylene blue (EMB) agar

Answer 14

E. coli

Question 15

Charcoal yeast extract agar buffered with cysteine and iron

Answer 15

Legionella (coal makes iron, needed for legions)

Question 16

Sarouraud’s agar

Answer 16

Fungi (“Sab’s a fun guy”)