Lab Identification of

S.pyogenes (Group A)

•Primary culture by pour or streak plate

•Domed,grayish/opalescent colonies

•Encapsulated cells produce mucoid colonies

Beta-hemolytic

• Zone several times greater than diameter of colony

TSA

S. pyogenes

Lab Identification of

S. pyogenes (Group A) (cont.)

Catalase Negative: Differentiates from Staphylococcus

Bacitracin test: presumptively distinguishing between Group A beta-hemolytic streptococci (bacitracin POS) and other beta- hemolytic streptococci that are isolated from pharyngeal swabs (95% sensitivity for Grp A strep)

Rapid Identification Tests:

Based on extraction of Group A carbohydrate directly from throat swabs

• ELISA, Coagglutination, Fluorescent Antibody

Group B Streptococcus

Streptococcus agalactiae

Group B Streptococcal Infections

Grp B Streptococcal Infections (cont.)

Age-Specific Attack Rates of Group B

Streptococcal Disease

Epidemiology of Neonatal Group B

Streptococcal Disease

Group B Streptococcus

S. agalactiae

Diagnostic Laboratory Tests

•CAMP factor positive

•Hippurase positive