1. Culture Media
Prof. Dr. Ihab Moussa

2. Culture 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. Classification of Media
Based on the consistency :
Solid media
Semisolid media
Liquid media

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

5. Constituents 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. Simple Media
Also called Basal medium
Most commonly used in routine labs.
e.g. Nutrient broth, NA

7. Enriched Media Blood, serum or egg added to the basal medium.
To grow bacteria which are more exacting in nutritional requirements.
e.g. Blood Agar, Chocolate Agar

8. Blood Agar Media

9. 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

10. Selective Media
Substances added to a solid media to favour the growth of wanted bacteria.
e.g. MacConkey agar media

12. Indicator Media
Change in the colour of indicator with the growth of bacteria.
e.g. Sulphite in Wilson Blair media for Salmonella typhi.

13. Differential Media
To bring out differing characteristics of bacteria.
e.g. MacConkey’s agar

14. Dr Ekta, Microbiology, GMCA
Composite Media
For identification of isolates
e.g. Triple Sugar Iron
Transport Media
For delicate organisms
Delay in transit
e.g. Stuart’s transport media
Oct 07
Dr Ekta, Microbiology, GMCA