3. Enrichment media Fluid media that increases the numbers of a pathogen by containing enrichments and/or substances that discourage the multiplication of unwanted bacteria. Eg. Selenite F broth media
Alkaline peptone water
4. Selective media Media which contain substances ( Eg. Antibiotics) that prevent or slow down the growth of bacteria other than pathogens for which the media are intended. Eg. Modified Thayer –Martin Agar
Salmonella-Shigella( SS) agar
1. Differential media Media to which indicator substances are added to differentiate bacteria. Eg. TCBS Agar differentiates sucrose fermenting yellow colonies of Vibrio cholerae to non-sucrose fermenting blue colonies other Vibrio species. NB: Most differential media distinguish between bacteria by an indicator which changes color when acid is produced following carbohydrate fermentation.
2. Transport media Media containing ingredients to prevent the overgrowth of commensals and ensure the survival of pathogenic bacteria when specimens can not be cultured soon after collection.