TCBS agar Use: selective medium of Vibrio cholorae (Figure n°8 ). Growth: V. cholorae gives yellow colonies due to fermentation of sucrose. Others vibrios give pale colonies because they not ferment sucrose (Figure n°9 ).
Gram positive rods with variable staining (Figure n°11 ) Ex: Clostridium perfringens Culture on Robertson cooked meat: Anaerobic medium used for isolation of Cl. Perfringens and others anaerobic bacteria. The color turned orange due to the saccharolytic activity of organism (Figure n°12).