Staphylococcus is a genus of bacteria that can cause a variety of infections in humans. S. aureus is one of the most common causes and produces toxins like enterotoxins that can lead to food poisoning. It also produces exfoliative toxins that cause skin infections like impetigo and toxic shock syndrome toxin-1 (TSST-1) that causes toxic shock syndrome. Treatment involves penicillin or other antibiotics, but some strains have developed resistance.

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

4. Physiology and Structure

5. Structure

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

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

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

23. Sites of infection

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.

28. TSS

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.

33. Pneumonia

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

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