Types of Culture media

Culture Media Culture Media

II MBBSDr Ekta Chourasia

Lecturer, Microbiology

Oct 07 Dr Ekta, Microbiology, GMCA

Culture MediaCulture MediaIndications/ Need for culture - Isolate bacteria in pure cultures. Demonstrate their properties. Obtain sufficient growth for preparation

of antigens & for other tests. Typing bacterial isolates. Antibiotic sensitivity. Estimate viable counts. Maintain stock cultures.

Oct 07 Dr Ekta, Microbiology, GMCA

Classification of MediaClassification of Media

Based on the consistency : Solid media Semisolid media Liquid media

Oct 07 Dr Ekta, Microbiology, GMCA

ClassificationClassification Based on the function or property: - Simple media - Enriched media - Enrichment broth - Selective media - Indicator media - Differential media - Composite media - Transport media

Oct 07 Dr Ekta, Microbiology, GMCA

Constituents Of MediaConstituents Of Media Agar or agar- agar Peptone - mixture of partially

digested proteins Yeast or meat extract NaCl Melting point : 98°C Solidifying point : 42°C % of agar : Solid media (2%)

Oct 07 Dr Ekta, Microbiology, GMCA

Simple MediaSimple Media Also called Basal medium Most commonly used in routine

labs. e.g. Nutrient broth, NA

Oct 07 Dr Ekta, Microbiology, GMCA

Enriched MediaEnriched Media Blood, serum or egg added to the

basal medium. To grow bacteria which are more

exacting in nutritional requirements.

e.g. BA, CA

Oct 07 Dr Ekta, Microbiology, GMCA

Enrichment Broth (media)Enrichment Broth (media)

For mixed cultures or materials containing more than one bacterium.

Contains substances which stimulates wanted bacteria & inhibits unwanted bacteria.

e.g. Tetrathionate broth

Oct 07 Dr Ekta, Microbiology, GMCA

Selective Media Selective Media Substances added to a solid media

to favour the growth of wanted bacteria.

e.g. TCBS agar for Vibrio cholerae

Oct 07 Dr Ekta, Microbiology, GMCA

Indicator Media Indicator Media Change in the colour of indicator

with the growth of bacteria. e.g. Sulphite in Wilson Blair media

for Salmonella typhi.

Oct 07 Dr Ekta, Microbiology, GMCA

Differential MediaDifferential Media To bring out differing

characteristics of bacteria. e.g. MacConkey’s agar

Oct 07 Dr Ekta, Microbiology, GMCA

Composite MediaComposite Media

For identification of isolates

e.g. Triple Sugar Iron

Transport Media

For delicate organisms

Delay in transit e.g. Stuart’s transport

media