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Staphylococcus

Staphylococcus. Staphylococceae family. Low G + C Cocci (spheres) Grapelike clusters 3 planes 1 micrometer diameter FA Nonmotile, NSF Halotoerant Catalase (+) Oxidase (-) +/- fermentation. Staphylococcus species. 61 species Important S. aureus S. epidermidis S. saprophyticus

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Staphylococcus

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  1. Staphylococcus

  2. Staphylococceae family • Low G + C • Cocci (spheres) • Grapelike clusters • 3 planes • 1 micrometer diameter • FA • Nonmotile, NSF • Halotoerant • Catalase (+) • Oxidase (-) • +/- fermentation

  3. Staphylococcus species • 61 species • Important • S. aureus • S. epidermidis • S. saprophyticus • S. pseudointermedius • Others • S. haemolyticus • S. capitus • S. hominis • S. xylosis • S. warneri

  4. Cell Wall

  5. Location • Ubiquitous • Normal flora • Skin • Mouth • Nose • Throat • Predisposing factors • Immunosuppression • Concurrent disease • AB resistance

  6. Epidemiology • Normal microbiotica • Direct transmission • Portal of Entry • Hair follicle • Break in skin • Respiratory • Complications • Bacteremia • Septecemia • Abscess

  7. Cytological Sample

  8. Pathogenesis • Immune evasion • Slime layer biofilm (microcapsule) • Evades phagocytosis • Protein A on cell wall • Binds to IgG @ Fc • Blocks opsonization • Adhesin proteins • Binds to fibrin/fibrinogen • Binds to ECM • laminin • fibronectin • collagen

  9. Enzymes • Coagulase • Catalase • Hyaluronidase • Lipase • Beta lactamase • Staphylokinase (plasminogen activator) • Proteases • DNase • FAME (fatty acid modifying enzyme)

  10. Staphylococcus Toxins • Cytolytic Toxins • Alpha = βhemolysis • Beta = sphingomyelinase • Delta • Gamma • Leukocidin = hemolysis • Leukotoxin = WBC destruction • Exfoliative toxin • ETA and ETB • Protease & esterase activity • Toxic Shock toxins • Enterotoxins (A-E)

  11. Superantigens • Enterotoxin • Food poisoning, V/D • TSS if B or C antigenic type • TSST-1: desquamation; TSS

  12. Virulence Factors Summary

  13. Staph aureus • Location • Mucous membranes • Moist areas • Diseases • Noninvasive • Food poisoning • Enterotoxin (V/D) • Cutaneous • Scalded skin • Impetigo • Folliculitis • Boils, styes, furunculosis • Systemic • Soft tissue infections

  14. Systemic Staph. aureus infections • TSS • Bacteremia • Endocarditis • Pneumonia • Meningitis • Osteomyelitis • Septic arthritis • UTI • Phlebitis

  15. Staphylococcal disease summary

  16. S. aureus • Dx • Isolation • DDx MRSA/VRSA • Tx • AB based on culture • Prevention • Wound cleansing • Hand washing

  17. MRSA • Hosptial associated • Community assoc.

  18. AMA/CDC poster

  19. VRSA vanA operon from enterococcus changes cell wall tripeptide sequence

  20. Opportunistic Staph pathogens • S. capitis • S. epidermidis • S. saprophyticus • S. xylosis

  21. S. epidermidis • Location • Normal skin flora • opportunistic pathogen • Skin/wound infections • Endocarditis • UTI • Exposure • Direct contact • Newborns • Elderly • Fomites • Catheters • Shunts • IV needles • Prosthetics

  22. S. saprophyticus • Pathogenesis • Fimbria • Adhesion proteins • Autolysins • Diseases • UTI/cystitis • Peritonitis • Enopthalmitis • Endocaritis • Septic arthritis

  23. S. xylosus • Commensal • Industry • Ferment meat • Red color of sausage • Ferment milk • Orange color of cheese • Pathogenicity • Biofilms • Enterotoxins • Disease • Nosocomial • UTI • Food poisoning (raw)

  24. S. capitis • Epidemiology • Skin microbiotica • Head predominantly • Pathogenicity • Coagulase (-) • AB resistance • Diseases • Valvular endocarditis • Neonatal septicemia • Osteomyelitis

  25. S. pseudointermedius • Animal microbiotica • Epidemiology • Zoonotic • Enterotoxins • +/- coagulase • Diseases • Pyoderma (animals) • Food poisoning

  26. Rapid Staph test

  27. Immunology • Hyperimmune serum • Capsular proteins • Surface adhesins • Vaccination • At risk population • ESRD • Dialysis patients • Premature infants • StaphVAX • Capsular proteins • Exotoxin A (Ps. Aeurginosa)

  28. Questions?

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