160 likes | 310 Views
Culture Media. Prof. Dr. Ihab Moussa. 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.
E N D
Culture Media Prof. Dr. Ihab Moussa
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.
Classification of Media • Based on the consistency : Solid media Semisolid media Liquid media
Classification • 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 • 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%)
Simple Media • Also called Basal medium • Most commonly used in routine labs. e.g. Nutrient broth, NA
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
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
Selective Media • Substances added to a solid media to favour the growth of wanted bacteria. e.g. MacConkey agar media
Indicator Media • Change in the colour of indicator with the growth of bacteria. e.g. Sulphite in Wilson Blair media for Salmonella typhi.
Differential Media • To bring out differing characteristics of bacteria. e.g. MacConkey’s agar
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 Dr Ekta, Microbiology, GMCA