Lecture pp5&6staphylococcus
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Lecture pp5&6staphylococcus

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  • Clockwise from Top Left Staphylococcal Scalded Skin Syndrome (SSSS) Bullous impetigo (localized form of SSSS) Pustular impetigo Septic embolization Toxic Shock Syndrome (TSS)

Lecture pp5&6staphylococcus Presentation Transcript

  • 1. Staphylococcus
  • 2. Classification • Family • Genus • Species Micrococcaceae Micrococcus and Staphylococcus S. aureus S. saprophyticus S. epidermidis M. luteusmore than 20 specie s
  • 3. Gram-Positive Cocci Enterococcus (Group D CHO) γ hemolytic (α or β) Enterococcus faecalis, E. faecium FAMILY Micrococcaceae (catalase positive) Coagulase-positive Staphylococcus aureus Coag.-neg. Staphylococcus epidermidis, S. saprophyticus FAMILY Streptococcaceae (catalase negative) Group A: β-hemolytic Streptococcus pyogenes Group B: β-hemolytic (occasionally α or γ) S. agalactiae Group C: β-hemolytic (α or γ) S. anginosus, S. equismilis Group D: α or γ hemolytic (β) S. bovis Group F: β-hemolytic S. anginosus Group G: β -hemolytic S. anginosus Viridans streptococci: (no group specific CHO) α or γ hemolytic S. mutans and S. salivarius, S. sanguis, S. mitis and S. milleri groups Streptococcus pneumoniae (no group CHO)(α-hemolytic)
  • 4. Morphology
  • 5. Morphology Staph vs. Strep Gram-positive cocci in clusters
  • 6. StreptococcusStaphylococcus
  • 7. Staphylococcus
  • 8. See Overheads ~~~~~~~~~~ TSS Foodborne Intoxication ~~~~~~~~~~
  • 9. MICROBIAL PATHOGEN ADHESIN RECEPTOR Staphylococcus aureus LLiippootteeiicchhooiicc aacciidd Unknown Staphylococcus spp. SSlliimmee llaayyeerr Unknown Group A Streptococcus LLTTAA--MM pprrootteeiinn ccoommpplleexx FFiibbrroonneeccttiinn Streptococcus pneumoniae Protein N-acetylhexosamine-gal Escherichia coli Type 1 fimbriae CFA 1 fimbriae P fimbriae D-MMaannnnoossee GM ggaanngglliioossiiddee P blood grp glycolipid Other Enterobacteriaceae Type 1 fimbriae D-Mannose Neisseria gonorrhoeae Fimbriae GD1 ganglioside Treponema pallidum P1, P2, P3 Fibronectin Chlamydia spp. Cell surface lectin N-acetylglucosamine Mycoplasma pneumoniae Protein P1 Sialic acid Vibrio cholerae Type 4 pili Fucose and mannose
  • 10. Cell-Associated Virulence Factors • Capsule or slime layer (glycocalyx) • Peptidoglycan (PG) • Teichoic acid is covalently linked to PG and is species specific: S. aureus ribitol teichoic acid (polysaccharide A) S. epidermidis glycerol teichoic acid (polysaccharide B) • Protein A is covalently linked to PG • Clumping factor (bound coagulase)
  • 11. Virulence Factors Extracellular Enzymes • Coagulases (bound or free) Antigenic • Hyaluronidase “spreading factor” of S. aureus • Nuclease Cleaves DNA and RNA in S. aureus • Protease Staphylokinase (fibrinolysin) • Lipases • Esterases
  • 12. Virulence Factors: Exotoxins • Cytolytic (cytotoxins; cytolysins)  Alpha toxin - hemolysin • Reacts with RBCs  Beta toxin • Sphingomyelinase  Gamma toxin • Hemolytic activity  Delta toxin • Cytopathic for: – RBCs – Macrophages – Lymphocytes – Neutrophils – Platelets • Enterotoxic activity  Leukocidin
  • 13. • Enterotoxin • Exfoliative toxin (epidermolytic toxin) • Pyrogenic exotoxins Virulence Factors: Exotoxins
  • 14. Pathogenesis • Pass skin – first line of defense  Benign infection • Phagocytosis • Antibody • Inflammatory response Chronic infections • Delayed hypersensitivity
  • 15. Clinical Manifestations/Disease • SKIN  folliculitis  boils (furuncles)  carbuncles  impetigo (bullous & pustular)  scalded skin syndrome •Neonates and children under 4 years
  • 16. Clinical Manifestations/Disease • Other infections  Primary staphylococcal pneumonia  Food poisoning vs. foodborne disease  Toxic shock syndrome
  • 17. Metastatic Infections •Bacteremia •Osteomyelitis disease of growing bone • Pulmonary and cardiovascular infection
  • 18. Coagulase-Negative Staphylococci • Staphylococcus epidermidis • S. saprophyticus
  • 19. Staphylococcal Lab ID & Diagnostic Tests • Microscopic • Lab isolation • Coagulase positive  S. aureus
  • 20. Mannitol Salts Agar (MSA) Staphylococcus aureus
  • 21. Catalase 2H2O2  O2 + 2H2O Streptococci vs. Staphylococci Differential Characteristics
  • 22. Catalase POS Staphylococcus Catalase NEG
  • 23. S. aureus Coagulase Fibrinogen  Fibrin Differential Characteristics
  • 24. Coagulase NEG Coagulase POS Staphylococcus aureus
  • 25. Treatment • Drain infected area • Deep/metastatic infections  semi-synthetic penicllins  cephalosporins  erythromycin  clindamycin • Endocarditis  semi-synthetic penicillin + an aminoglycoside
  • 26. Prevention • Carrier status prevents complete control • Proper hygiene, segregation of carrier from highly susceptible individuals • Good aseptic techniques when handling surgical instruments • Control of nosocomial infections
  • 27. REVIEW
  • 28. Gram-Positive Cocci Enterococcus (Group D CHO) γ hemolytic (α or β) Enterococcus faecalis, E. faecium FAMILY Micrococcaceae (catalase positive) Coagulase-positive Staphylococcus aureus Coag.-neg. Staphylococcus epidermidis, S. saprophyticus FAMILY Streptococcaceae (catalase negative) Group A: β-hemolytic Streptococcus pyogenes Group B: β-hemolytic (occasionally α or γ) S. agalactiae Group C: β-hemolytic (α or γ) S. anginosus, S. equismilis Group D: α or γ hemolytic (β) S. bovis Group F: β-hemolytic S. anginosus Group G: β -hemolytic S. anginosus Viridans streptococci: (no group specific CHO) α or γ hemolytic S. mutans and S. salivarius, S. sanguis, S. mitis and S. milleri groups Streptococcus pneumoniae (no group CHO)(α-hemolytic) REVIEW
  • 29. REVIEW Which features are only found in S. aureus? S. epidermidis S. aureus
  • 30. REVIEW
  • 31. REVIEW
  • 32. REVIEW
  • 33. REVIEW
  • 34. REVIEW