Staphylococcus (1)
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Staphylococcus (1) Presentation Transcript

  • 1. Staphylococcus Eva L. Dizon, M.D.,FPPS,FPIDSP
  • 2. Staphylococcus Staphyle- Bunch of grapes 0.5 to 1 um Non motile Aerobic or Facultative Anaerobic Catalase positive Grow in media containing 10% NaCl at temp 18 to 40 C Present on the skin and mucuos membrane
  • 3. Species
    • S. aureus
    • S. epidermidis
    • S. saphrophyticus
    • S. capitis
    • S. haemolyticus
    • Micrococcus sp
    • Stomatococcus mucilaginosus
    • Alloiococcus otitidis
  • 4. Physiology and Structure
  • 5. Structure
  • 6.  
  • 7. Structure CAPSULE - loose fitting polysaccharide layer (slime layer) - protects bacteria by inhibiting chemotaxis and phagocytosis - facilitates adherence of bacteria to catheters and synthetic materials PEPTIDOGLYCAN - half of the cell wall - consist of layers of glycan chains with alternating subunits of N –acetylmuramic acid and N- acetylglucosamine - has endotoxin like activity
  • 8. Structure TEICHOIC ACID- phosphate containing polymers bound to peptidoglycan layer or to cytplasmic membrane - mediates the attachment of staphylococcus to mucosal surfaces S. aureus Ribitol teichoic acid with N-acetylglucosamine ( Polysaccharide A) S. epidermidis glycerol teichoic acid with glucosyl residues (polysaccharide B)-
  • 9. PROTEIN A- covalentlylinked to peptidoglycan - has affinity to Fc receptor of Ig - blocks opsonization and phagocytosis
  • 10. Structure CYTOPLASMIC MEMBRANE- osmotic barrier for the cell and provides an anchorage for the biosynthetic and respiratory enzyme COAGULASE and other SURFACE PROTEIN -Clumping factor or Bound coagulase binds fibrinogen convert to insoluble fibrin causing staphylococcus to clump - collagen , elastin and fibronectin binding protein
  • 11. Toxins
    • A. 5 Cytolytic or membrane damage toxin
    • Alpha
    • Beta
    • Gamma
    • Delta
    • Panton Valentine
    • B. 2 Exfoliative toxin
    • C. 8 Enterotoxin
    • D. Toxic Shock Syndrome Toxin(TSST 1)
  • 12. Cytotoxins Lyse neutrophils  release of lysosomal enzymes  damage sorrounding tissues Alpha toxin – disrupts the smooth muscle in blood vessels - toxic to erythrocytes, hepatocytes, platelets, cultivated cells - integrates to host cell membrane  pores  efflux of K and influx of Na,Ca  osmotic swelling  cell lysis - septic shock
  • 13. Cytotoxin Beta Toxin - Sphingomyelinase C - specific for sphingomyelin and lysophosphatidylcholine - toxic to RBC, WBC,Macrophage and fibroblast - catalyze hydrolysis of membrane phospholipids in susceptible cells - tissue destruction and abscess formation Delta toxin- disrupts cell membrane - toxic to variety of cells
  • 14. Cytotoxin
    • Gamma toxin and Panton Valentine
    • -both damage membrane of susceptible cells
    • - lyze nuetrophils and macrophages
    • - cell lysis is mediated by pore formation
    • Cause necrotizing skin infection
    • -PVL -potent leukotoxicity
  • 15. Exfoliative toxin
    • ETA - heat stable
    • ETB – heat labile
    • Serine protease
    • Exposure  splitting of desmosomes or intercellular bridges in the stratum granulosum epidermis
    • Common in neonates – ETA and ETB binds to GM4 like glycolipids present in neonates
  • 16. Enterotoxin
    • A-E, G-I
    • Stable to heating , resistant to hydrolysis
    • Enterotoxin A – most commonly associated with disease
    • Enterotoxin C and D- contaminated milk products
    • Enterotoxin B- Pseudomembranous colitis
    • Superantigens
  • 17.  
  • 18. TSST-1
    • Formerly pyrogenic exotoxin C and entertoxin F
    • Induce cytokine release from macrophage and T lymphocytes
    • Increase sensitivity to endotoxin
    • Produce leakage of endothelial cells
    • Penetrate mucosal barrier
  • 19. Staphylococcal enzymes convert fibrinogen react with globulin plasma factor insoluble fibrin to form staphylothrombin Clumping Cause formation of fibrin layer around abscess protecting staphylococcus from phagocytosis Coagulase Bound Free
  • 20. Staphylococcal enzymes
    • Catalase - catalyze the conversion of toxic hydrogen peroxide to water and oxygen
    • Hyalurodinase - hydrolyzes hyaluronic acid in acellular matrix of connective tissue  spread
  • 21. Staphylococcal enzymes
    • Fibrinolysin- staphylokinase . Dissolve fibrin clot- aid in bacterial spreading
    • Lipases hydrolyse lipid to ensure survival in sebaceous areas of the body
    • Nuclease
    • Penicillinase- plasmid
    • Fatty acid modifying enzyme (FAME)- antibacterial lipid- prolonged bacterial survival
  • 22. Epidemiology
    • Transient colonizer of skin
    • Nasal carriage – anterior nasopharynx
    • Persistent carrier – hospital personnel
    • Killed by high temperature and disinfectant
    • Direct contact, fomites
    • Handwashing
  • 23. Sites of infection
  • 24. Ritters disease or SSSS
    • Perioral erythema  spread  body  bullous  desquamation
    • Nikolsky sign
    • Bullous impetigo – localized form of SSSS - localized blister - culture positive
  • 25. SSSS most commonly in children and neonates. Starts abruptly with perioral (around the mouth) erythema with sunburn-like rash rapidly turning bright red spreading to bullae (large vesicle appearing as a circumscribed area) in 2-3 days and desquamating (peeling) within 5 days.
  • 26. Staphylococcal food poisoning
    • Ham , salted pork, custard, potato sald, ice cream
    • Hands, Nasal carriage
    • I.P. – 4 hrs
    • Vomiting, diarrhea, abd. pain
  • 27. Toxic shock syndrome
    • Growth of organism in vagina or wound  release of TSST-1
    • Fever, macular erythematous rashes, hypotension, multiorgan involvement, desquamation of palm and sole
  • 28. TSS
  • 29. Cutaneous infection
    • Impetigo
    • Folliculitis
    • Furuncle
    • Carbuncle
    • Wound infection
  • 30. Folliculitis - superficial folliculitis is essentially a staphylococcal impetigo in which a small area of erythema develops around a hair follicle and subsequently becomes a dome-shaped pustule. Carbuncle - a deep-seated pyogenic infection of the skin and subcutaneous tissues.
  • 31. Impetigo - a contagious superficial pyoderma, caused by S. aureus and Streptococcus pyogenes, that begins with a superficial flaccid vesicle which ruptures and forms a thick yellowish crust, most commonly occurring in the face.
  • 32. Others
    • Bacteremia
    • Endocarditis
    • Pneumonia
    • Empyema
    • Osteomyelitis
    • Septic arthritis
  • 33. Pneumonia
  • 34. S.Epidermidis and CNS
    • Endocarditis- native or artificial valves
    • Catheter and shunt infection
    • Prosthetic joint infection
    • UTI
  • 35. Laboratory diagnosis Microscopy Culture Grow rapidly within 24 hours Large, golden, smooth colonies Blood Agar- hemolysis Selective media- add NaCl 7.5% Mannitol – fermented by S. aureus Serology Insensitive Antibody against teichoic acid Bacteremia. Endocarditis After 2 weeks
  • 36. Culture – S. aureus
  • 37. S. epidermidis S. saphrophyticus
  • 38. Coagulase test Showing positive (upper tube) and negative (lower tube) coagulase tests.
  • 39. Mannitol Salt Agar test
  • 40. Identification
    • Biochemical testing Coagulase Heat stable nuclease Alkaline phospatase
    • Mannitol fermentation test
  • 41. Treatment and Prevention
    • Semisynthetic penicillinase resistant penicillin
    • Resistance ( mecgene A –codes for PBP 2’)
  • 42.  
  • 43.  
  • 44. Thank You