Culture media

THE USE OF APPROPRIATE CULTURE MEDIA FOR THE

IDENTIFICATION OF BACTERIA

Made by : Group# C1

Fasahat Ahmed Butt (36)

CULTURE MEDIA A culture medium is a compound , which

has constituents that are essential for life , multiplication and growth of micro-organisms.

1) Nutrients

2) Mineral salts

3) suitable pH

4)Accessory growth factors

CLASSIFICATION OF CULTURE MEDIA

ACCORDING TO PHYSICAL STATE

(A) LIQUID MEDIUM:1) Peptone water2) Nutrient Broth

(B) SOLID MEDIUM: 1) Nutrient agar

ACCORDING TO CONSTITUENTS

Simple media Enriched media Differential media Selective media Transport media

SIMPLE MEDIA

Consists of only basic substances such as, nitrogen , carbon , minerals.

EXAMPLES: Nutrient broth Nutrient agar Peptone water

ENRICHED MEDIA

Some enriched material like blood and serum is added to the medium , required for proper growth of some bacteria

EXAMPLES: Blood agar Chocolate agar

DIFFERENTIAL MEDIA

This type of media is used to differentiate between two groups of bacteria .

EXAMPLES: MacConkey’s medium

SELECTIVE MEDIA

An inhibitory substance is added to the media which prevents growth of all organisms except the one for which it is designed.

EXAMPLES: Loweistein jensen’s medium

TRANSPORT MEDIA A media used to transport specimen to

keep the organism alive EXAMPLES: AMIE’s medium

HOW TO IDENTIFY BACTERIA’S USING CULTURE MEDIA ????

NUTRIENT AGAR

MICRO-ORGANISMS CULTURED: Staph.aureus golden yellow

colonies Staph.citrus lemon yellow

colonies Pseudomonas green colonies

BLOOD AGAR

MICRO-ORGANISMS CULTURED: Complete (beta) hemolysis: Strep.pyogenes In complete (alpha) hemolysis: Streptococcus pnuemonia Non-hemolytic : staph.aureus and staph.citrus

CHOCOLATE AGAR

MICRO-ORGANISMS CULTURED: 1)H.influenza 2)Neisseria.meningitidis

MACCONKEY’S MEDIUM MICRO-ORGANISMS CULTURED: 1) lactose fermenters (pink colonies): E.coli. 2) non-lactose fermenters (colour less

colonies): shigella

LOWENSTEIN-JENSEN MEDIUM

MICRO-ORGANISMS CULTURED: Mycobacterium tuberculosis