Culture Media Prof Dr Ihab Moussa Culture Media
Culture Media Prof. Dr. Ihab Moussa
Culture Media Indications/ Need for culture l Isolate bacteria in pure cultures. l Demonstrate their properties. l Obtain sufficient growth for preparation of antigens & for other tests. l Typing bacterial isolates. l Antibiotic sensitivity. l Estimate viable counts. l Maintain stock cultures.
Classification of Media l Based on the consistency : Solid media Semisolid media Liquid media
Classification l Based on the function or property: - Simple media - Enriched media - Enrichment broth - Selective media - Indicator media - Differential media - Composite media - Transport media
Constituents Of Media l l l l Agar or agar- agar Peptone - mixture of partially digested proteins Yeast or meat extract Na. Cl Melting point : 98°C Solidifying point : 42°C % of agar : Solid media (2%)
Simple Media l l Also called Basal medium Most commonly used in routine labs. e. g. Nutrient broth, NA
Enriched Media l l 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
Blood Agar Media
Enrichment Broth (media) l l For mixed cultures or materials containing more than one bacterium. Contains substances which stimulates wanted bacteria & inhibits unwanted bacteria. e. g. Tetrathionate broth
Selective Media l Substances added to a solid media to favour the growth of wanted bacteria. e. g. Mac. Conkey agar media
Indicator Media l Change in the colour of indicator with the growth of bacteria. e. g. Sulphite in Wilson Blair media for Salmonella typhi.
Differential Media l To bring out differing characteristics of bacteria. e. g. Mac. Conkey’s agar
Composite Media l For identification of isolates e. g. Triple Sugar Iron Transport Media l l For delicate organisms Delay in transit e. g. Stuart’s transport media Oct 07 Dr Ekta, Microbiology, GMCA
- Slides: 14