Streptococcal Identification

Laboratory testing algorithm for groups A, B, D, and pneumococci.

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Gram Stain
Gram positive Cocci - Chains

Catalase Test
Negative

Streptococci

Beta-hemolysis on Blood Agar
Bacitracin Sensitive

Group A Streptococcus (S. pyogenes)

Beta Hemolysis on Blood Agar
CAMP Test Positive

Group B Streptococcus (S. agalactiae)

Alpha Hemolysis on Blood Agar
Optochin Sensitive

Streptococcus pneumoniae (pneumococcus)

Alpha Hemolysis on Blood Agar
Optochin Negative

Streptococcus, viridans group

Gamma Hemolysis on Blood Agar

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Bile Esculin Agar Positive

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Growth in BHI Broth with 6.5% NaCl

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Group D enterococcus

Gamma Hemolysis on Blood Agar

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Bile Esculin Agar Positive

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No Growth in BHI Broth with 6.5% NaCl

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Group D non-enterococcus