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Staphylococcus

Pathogenic and opportunistic cocci . Classification, biological properties. Staphylococci, streptococci, gonococci and meningococci. Staphylococcus. Classification Family – Micrococcaceae Genus – Staphylococcus Species: S. aureus S. epidermidis S. saprophyticus.

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Staphylococcus

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  1. Pathogenic and opportunistic cocci. Classification, biological properties. Staphylococci, streptococci, gonococci and meningococci.

  2. Staphylococcus Classification • Family – Micrococcaceae • Genus –Staphylococcus • Species: • S. aureus • S. epidermidis • S. saprophyticus

  3. Staphylococci in the pure culture and in the pus smears

  4. Culture • They grow readily on ordinary culture media • The optimal temperature being 370C and pH 7,4-7,6 • They are aerobes and facultative anaerobes • Culture media: nutrient agar, blood agar, salt media

  5. Differentiation of the S.aureus from opportunists Hemolysis appearance on the blood agar DNAase activity (on the top)

  6. Differentiation of the staphylococci Coagulase activity (test is positive for S.aureus) Novobiocin disk test to differentiate S.saprophyticus (left) and S.epidermidis (right)

  7. Pathogenesis • Staphylococcal diseases may be classified as • Cutaneous infections • Deep infections • Food poisoning • Nosocomial infections (hospital infections) • Skin exfoliative disease (staphylococcal scalded skin syndrome) • Toxic shock syndrome

  8. Laboratory diagnosis • Direct microscopy • Culture.

  9. The characteristics help to distinguish the pathogenic strains from non-pathogenic strains • Beta type of haemolysis on blood agar • Production of a golden yellow pigment • Coagulase production • Mannitol fermentation • Gelatin liquefaction • Phosphatase production • Production of enzyme deoxyribonuclease • Tellurite reduction

  10. Prophylaxis • General prophylaxis.

  11. Staphylococcus aureus

  12. Streptococcus Classifications: A. Due to type of hemolysis B. Lancefield´s classification (serological) C. Due to phylogenetic relationship

  13. Different types of hemolysis Α -Hemolysis Β-Hemolysis Γ-Hemolysis

  14. S.pyogenes (smears from the agar culture(on the left) and sugar broth (on the right)

  15. S.pneumoniae (smears from the pure culture and from the sputum)

  16. Culture • aerobes and facultative anaerobes • media containing blood, serum or sugars.

  17. Laboratory diagnosis • Suppurative infections : microscopy and pure culture isolation • Non-suppurative sequelae: serology

  18. Streptococcus pyogenes

  19. Neisseria • Classification • Family - Neisseriaceae • Genus – Neisseria • Species: • N. meningitidis • N. gonorrhoeae

  20. N. meningitidis in the smears from the pure culture and clinical sample

  21. Culture • They are strict aerobes. • The optimum temperature and pH for growth are 35-360C and 7,4-7,6 respectively. • Growth occurs in media enriched with blood, serum or ascitic fluid.

  22. Antigenic classification • N. meningitidis has been divided into 13 serogroups

  23. Laboratory diagnosis • Direct microscopy • Antigen detection • Culture. • Serology • Polymerase chain reaction.

  24. Prophylaxis • Chemoprophylaxis • Immunoprophylaxis.

  25. Neisseriameningitidis

  26. N. gonorrhoeae

  27. Laboratory diagnosis • Direct microscopy. • Culture. • Serology

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