A short description of different types of media

1. Culture MediaCulture Media
II MBBS
Dr Ekta Chourasia
Lecturer, Microbiology

2. Oct 07 Dr Ekta, Microbiology, GMCA
Culture MediaCulture Media
Indications/ 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.

3. Oct 07 Dr Ekta, Microbiology, GMCA
Classification of MediaClassification of Media

Based on the consistency :
Solid media
Semisolid media
Liquid media

4. 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

5. 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%)

6. Oct 07 Dr Ekta, Microbiology, GMCA
Simple MediaSimple Media

Also called Basal medium

Most commonly used in routine labs.
e.g. Nutrient broth, NA

7. 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

8. 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

9. Oct 07 Dr Ekta, Microbiology, GMCA
Selective MediaSelective Media

Substances added to a solid media to
favour the growth of wanted bacteria.
e.g. TCBS agar for Vibrio cholerae

10. Oct 07 Dr Ekta, Microbiology, GMCA
Indicator MediaIndicator Media

Change in the colour of indicator with
the growth of bacteria.
e.g. Sulphite in Wilson Blair media
for Salmonella typhi.

11. Oct 07 Dr Ekta, Microbiology, GMCA
Differential MediaDifferential Media

To bring out differing characteristics
of bacteria.
e.g. MacConkey’s agar

12. 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