Practical Cardiovascular System By Dr. Emad AbdElhameed Morad Lecturer of Medical Microbiology and Immunology
Streptococci Group A beta hemolytic streptococci (Streptococcus pyogenes)
LAB diagnosis Streptococcus pyogenes • Specimen: • Throat swab in case of follicular tonsillitis. • Direct smear stained with gram stain: • Shows Gram positive cocci in chains + pus cells. • Culture: • Done on blood agar at 37 degree. • Beta hemolytic colonies are obtained + catalase –Ve. • Bacitracin test: • This bacterium is sensitive to bacitracin.
Beta hemolysis Gram positive cocci in chains + pus cells
Laboratory diagnosis of rheumatic fever: C-reactive protein (CRP): latex agglutination test. Antistreptolysin O titer (ASOT): latex agglutination test. A titer of 200 IU/ml or more is significant. Erythrocyte sedimentation rate (ESR).