Media

Enrichment media

Basic media containing additives such as blood or serum which enhance the growth of many fastidious and non-fastidious organisms.

Blood Agar Plate (BAP)

. Common enrichment media 2. grows many organisms 3. shows hemolysis
Hemolytic Patterns: Alpha (  )- green zone due to partial destruction of RBC surrounding colony Beta ( )- clear zone due to total destruction of RBC
surrounding colony Gamma ( )- no Hemolysis

Chocolate Agar CHOC

n enrichment medium of many organisms especially Heamophilus sp. and Neisseria gonorrhea which will only grow on Choc. Agar

Mueller Hinton Agar (MH)

An enrichment medium for many kinds of organisms. It is used for the Kirby- Bauer sensitivity test.

Nutrient Broth (N Broth)

Grows many organisms including anaerobes and can recover small amounts of organisms in cultures.

Selective Media

Media that contains chemicals or dyes that prevent or retard growth of certain organisms and select or allow growth of other organisms without
necessarily differentiating them

Differential Media

media that allows the growth of groups of organisms and demonstrates certain characteristics. Most differential media is also selective.

Mannitol Salt Agar

1. used to isolate staphylococcus species, 2. The high salt concentration (7.5%) allows the medium to be selective for Staphylococcus
since most organisms cannot tolerate that high salt content, 3. Staph. aureus appears yellow, 4. Staph. epidermidis appears pink

MacConkey Agar (MAC))

1. A
selective, differential medium for the isolation of gram negative rods (bacilli), 2. Gram positive organisms and coliform organisms are inhibited by the bile salts
mixture, 3. Lactose fermenters are hot pink to red, non-lactose fermenters form colorless or very light pink colonies.

Salmonella Shigella Agar (SS)

1. A selective,
differential medium for the isolation of Salmonella and Shigella which is a gram negative rods from feces or rectal swabs, 2. Gram positive organisms and coliform
organisms are inhibited by the bile salts mixture, 3. Lactose fermenters are hot pink to red, 4. non-lactose fermenters form colorless or very light pink colonies.
SS Agar shows H2S production,

MAC Agar

Does not show H2S

Hektoen Enteric Agar (HE)

1. A selective, differential medium for the isolation of Salmonella and Shigella which is a gram
negative rods from feces or rectal swabs, 2. Gram positive organisms and coliform organisms are inhibited by the bile salts mixture, 3. Lactose fermenters are yellow
4. non-lactose fermenters green colonies

Colistin Nalidixic Acid (CNA)

nhance the growth of most gram positive organisms. Colistin and nalidixic acid is the
inhibitor agent that inhibits the growth of gram negative organisms.

biochem

SIM, MRVP, Simmons Citriate, and TS