Quick Review Cards for Medical Laboratory Science

Routine Media for Aerobes and Facultative

Anaerobes

Clinical Microbiology Review 149

MEDIUM TYPE FOR ISOLATION OF OTHER

Sheep blood agar (SBA)

Chocolate agar (CHOC)

Columbia colistin–nalidixic
acid agar (CNA)

Phenylethyl alcohol agar
(PEA)

Group A–selective strep agar
with 5% sheep blood (SSA)

Eosin methylene blue (EMB)

MacConkey (MAC) agar

Sorbitol MacConkey
(SMAC) agar

Tryptic soy agar with 5% sheep blood. Allows differen-

tiation of hemolysis.

Supplies X & V factors. Incubate in ↑CO 2.

Colistin & nalidixic acid suppress most GN. Contain

5% sheep blood.

Phenylethyl alcohol inhibits enteric GNR. Contains

5% sheep blood.

Contains antibiotics to suppress normal throat flora.

Group B strep will also grow.

Eosin & methylene blue inhibit GP. Lactose fermenters

(LF) green-black or purple. E. coliproduces green metallic

sheen. Non–lactose fermenters (NLF) colorless.

Bile salts & crystal violet inhibit most GP. LF pink. NLF

colorless.

E. coli O157:H7doesn’t ferment sorbitol. Colorless

colonies. Some labs have stopped using because

non-O157 serotypes can be pathogens.

E, D

E

S

S

S

S, D

S, D

S

Most nonfastidious bacteria

Haemophilus& Neisseria

GP

GPC & anaerobic GNR

Group A strep from respiratory

sources

Enteric GNR

Enteric GNR

E. coli O157:H7

continued...