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Lecture pp5&6staphylococcus
- 3. Classification • Family • Genus • Species Micrococcaceae Micrococcus and Staphylococcus S. aureus S. saprophyticus S. epidermidis M. luteusmore than 20 specie s
- 4. 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)
- 5. Morphology
- 6. Morphology Staph vs. Strep Gram-positive cocci in clusters
- 14. 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
- 15. 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)
- 16. 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
- 17. 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
- 18. • Enterotoxin • Exfoliative toxin (epidermolytic toxin) • Pyrogenic exotoxins Virulence Factors: Exotoxins
- 19. Pathogenesis • Pass skin – first line of defense Benign infection • Phagocytosis • Antibody • Inflammatory response Chronic infections • Delayed hypersensitivity
- 20. Clinical Manifestations/Disease • SKIN folliculitis boils (furuncles) carbuncles impetigo (bullous & pustular) scalded skin syndrome •Neonates and children under 4 years
- 21. Clinical Manifestations/Disease • Other infections Primary staphylococcal pneumonia Food poisoning vs. foodborne disease Toxic shock syndrome
- 22. Metastatic Infections •Bacteremia •Osteomyelitis disease of growing bone • Pulmonary and cardiovascular infection
- 24. Coagulase-Negative Staphylococci • Staphylococcus epidermidis • S. saprophyticus
- 27. Staphylococcal Lab ID & Diagnostic Tests • Microscopic • Lab isolation • Coagulase positive S. aureus
- 28. Mannitol Salts Agar (MSA) Staphylococcus aureus
- 29. Catalase 2H2O2 O2 + 2H2O Streptococci vs. Staphylococci Differential Characteristics
- 31. S. aureus Coagulase Fibrinogen Fibrin Differential Characteristics
- 33. Treatment • Drain infected area • Deep/metastatic infections semi-synthetic penicllins cephalosporins erythromycin clindamycin • Endocarditis semi-synthetic penicillin + an aminoglycoside
- 34. 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
- 36. REVIEW
- 37. 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
- 38. REVIEW Which features are only found in S. aureus? S. epidermidis S. aureus
- 39. REVIEW
- 40. REVIEW
- 41. REVIEW
- 42. REVIEW
- 43. REVIEW
Notes de l'éditeur
- Clockwise from Top Left Staphylococcal Scalded Skin Syndrome (SSSS) Bullous impetigo (localized form of SSSS) Pustular impetigo Septic embolization Toxic Shock Syndrome (TSS)