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Streptococci. Colonial morphology Microscopic appearance Lancefield grouping - How to distinguish between Streptococci. Streptococci. Streptococcus pneumoniae. Streptococcus pneumoniae.
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Streptococci Colonial morphology Microscopic appearance Lancefield grouping - How to distinguish between Streptococci
- On Blood Agar: Translucent or mucoid colonies, 1-2 mm in diameter, raised colonies in young cultures but later become flattened with raised edges.
Streptococcuspyogenes - On Blood Agar: small 0.5 – 1 mm in diameter colourless colonies, dry, shiny or mucoid beta haemolytic colonies.
- On Blood Agar: grey mucoid colonies, 2mm in diameter surrounded by small zone of Beta-haemolysis.
CAMP Test - CAMP factor is an extracelluar diffusible protein produced by S.agalactiae - This protein interacts with the staphylococcal beta-lysin on sheep blood agar producing enhanced haemolysis. - arrow-head shaped area of haemolysis where the staphylococcal organism meets the test organism.
Aesculinis incorporated into agar with ferric citrate and bile salts • bile aesculin agar. • Hydrolysis of the aesculin forms aesculetinand glucose. • The aesculetin forms dark brown or black complexes with ferric citrate.