1. Streptococcaceae family Classification - Includes 7 genera: –Streptococcus – a major cause of human infections –Enterococcus – frequent cause of human infections –

2. Streptococci Characters of Streptococci –Gram positive cocci –1 µ m in diameter –Chains or pairs –Usually capsulated –Non motile –Non spore forming –Facultative anaerobes –Fastidious –Catalase negative (Staphylococci are catalase positive)

3. Classification of Streptococci Streptococci can be classified according to: –Oxygen requirements Anaerobic (Peptostreptococcus) Aerobic or facultative anaerobic (Streptococcus) –Serology (Lanciefield Classification) –Hemolysis on Blood Agar (BA)

4. Serology: Lanciefield Classification Streptococci classified into many groups from A-K & H-V Classification based on C- carbohydrate antigen of cell wall –Groupable streptococci A, B and D (more frequent) C, G and F (Less frequent) Streptococci Group A S. pyogenes Group B S. agalactiae Group C S. equisimitis Group D Enterococcus Other groups (E-U) Lanciefield classification

5. Classification of Streptococci Based on Hemolysis on Blood Agar Hemolysis on BA –  -hemolysis Partial hemolysis Green discoloration around the colonies e.g. non-groupable streptococci (S. pneumoniae & S. viridans) –  -hemolysis Complete hemolysis Clear zone of hemolysis around the colonies e.g. Group A & B (S. pyogenes & S. agalactiae) –  -hemolysis No lysis e.g. Group D (Enterococcus spp) Streptococci  -hemolysis  -hemolysis  -hemolysis

6. Hemolysis on Blood agar  -hemolysis  -hemolysis  -hemolysis

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8. 8 Human Streptococcal Pathogens S. pyogenes (Group A) S. agalactiae (Group B) Viridans streptococci S. pneumoniae Enterococcus faecalis (Group D)

9. Differentiation between  -hemolytic streptococci CAMP test BacitracinsensitivityHemolysis NegativeSusceptible S. pyogenes PositiveResistant S. agalactiae Inulin Fermentation Bile solubility Optochin sensitivity Hemolysis Not ferment Soluble Sensitive (≥ 14 mm)  S. pneumoniae FermentInsolubleResistant (≤13 mm)  Viridans strep Differentiation between  -hemolytic streptococci

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11. Bacitracin sensitivity

12. CAMP test

13. Differentiation between  -hemolytic streptococci CAMP test BacitracinsensitivityHemolysis NegativeSusceptible S. pyogenes PositiveResistant S. agalactiae Inulin Fermentation Bile solubility Optochin sensitivity Hemolysis Not ferment Soluble Sensitive (≥ 14 mm)  S. pneumoniae FermentInsolubleResistant (≤13 mm)  Viridans strep Differentiation between  -hemolytic streptococci

14. Optochin Susceptibility Test Optochin susceptible S. pneumoniae Optochin resistant S. viridans

15. Capsule staining Negative Staining India Ink Congo Red NigrosinEosin

17. anthony's stain method لام را در معرض هوا خشک کنید نباید آن را با حرارت ، ثابت کرد با محلول آبی کریستال ویوله ۱٪ رنگ آمیزی به مدت ۲ دقیقه انجام می شود شستشوی لام با محلول سولفات مس ۲۰٪ انجام می شود لام را در معرض هوا خشک کنید و با عدسی ۱۰۰ و روغن ایمرسیون ، لام را بررسی کنید