Microbiology 211 Lab Exercise 6

Front 1

Defined media

Back 1

Defined media is composed of known amounts of pure chemicals, where the exact chemical composition is known.
They are used to culture non-fastidious heterotrophic bacteria.

Front 2

Complex media

Back 2

The exact chemical composition is not known.
They are composed of complex nutrients that are rich in vitamins and nutrients.
They contained more performed building blocks.

Front 3

Selective media

Back 3

Selective media allow for the growth of a particular group of microorganisms while inhibiting another group of bacteria.
They are used to isoate Staphylococcus sp. from normal flora population.

Front 4

Differential media

Back 4

Differential media is useful in identifying specific biochemicals traits (sugar fermentation, indole production, citrate utilization) that will aid in the identification of a microorganism.
It allows for the growth all bacteria but will provide a color change.

Front 5

Selective and Differential media

Back 5

It combines the traits of selective media and differential meida.
It also has color indicator to differentiate color changes among different groups of bacteria.
Examples: MacConkey agar, mannitol salts agar.

Front 6

Glucose salts agar (GSA)

Back 6

defined media. Only organisms that are capable of making all their growth factors from glucose and inorganic salts will be able to grow on this type of media.
Not used to determine glucose fermentation.

Front 7

Trypticase soy agar (TSA)

Back 7

complex media. This is a rich, undefined medium made from an enzymatic digest of protein and soy product.

Front 8

MacConkey agar (MAC)

Back 8

selective and differential media.
It contains bile salts and crystal violet that inhibit the growth of Gram positive bacteria while allowing the growth of gram negative bacteria.
It also contains lactose and a color indicator that allows for the identification of bacteria that can that ferment lactose (purple) and those unable to ferment lactose.

Front 9

Escherichia coli

Back 9

Gram negative bacillus.
Produces irregular raised colonies on TSA.
lac+

Front 10

Enterobactor aerogenes

Back 10

Gram negative rod
Lac+

Front 11

Pseudomonas aeruginosa

Back 11

gram negative rod
Lac-

Front 12

Staphylococus epidermidis

Back 12

Gram positive
can grow on TSA
cannot grow on GSA, MAC

Front 13

Fastidious

Back 13

Organisms that are unable to make their own performed building blocks (fatty acids, amino acids, purines, pyrimidines, and vitamins) for grwoth which much be added to the growth medium.

Front 14

Escherichia coli

Back 14

Gram negative bacillus
TSA :+
GSA: +
MAC: +, lac +

Front 15

Enterobactor aerogenes

Back 15

Gram negative bacillus
TSA: +
GSA: +
MAC: +, lac + (light pink)

Front 16

Pseudomonas aeruginosa

Back 16

Gram negative bacillus
TSA: +
GSA: +
MAC: +, lac-

Front 17

Staphylococcus epidermidis

Back 17

Gram positive
TSA: +
GSA: -
MAC:-, lac n/a

Front 18

Mannitol salts agar

Back 18

Gram+ staphylococci (S. aureus): fermenting mannitol, media changes color to yellow

Gram+staphylococci (S. epidermidis): not fermenting, no color change

Gram+streptococci: inhibit growth

Gram -: inhibit growth