STREPTOCOCCUS

• Streptococcus spp.


  Gram (+) cocci, non-motile, non-spore forming, Catalase (-)
• Hemolysis

  Alpha - streptococcus viridans

  Beta - streptococcus pyogenes

  Gamma - enterococcus
• Lancefield Classificiation A, B, C, F, G


  Causes disease in humans
• Streptococcus pyogenes


  Pus-producing Group A Beta-Hemolytic Strep (GABHS)
• Streptococcus Fibrinogen Binding Protein


  Used to attach to host cells
• M Protein


  Penetrates and projects from the streptococcal cell wall
• Hyaluronidase


  Used for connective tissues in blood vessels
• Streptolysin O and S

  O - deep cuts in agar plates

  S - surface of blood agar plates
• Spe A and C


  Superantigens
• Streptococcal pharyngitis


  Red, swollen tonsillitis with pus
• Impetigo


  Itchy hone-colored crusts on skin
• Erysipelas


  Warm, painful, raised lesions
• Necrotizing fasciitis


  Purple discoloration and pain over infected area
• Scarlet Fever

  • Bright red skin rash that feels like sand paper
  • Flushed red face, but pale around mouth
• Acute Rheumatic Fever


  Joint inflammation
• Syndenham’s chorea


  Rapid involuntary movement of the face and the hands
• Treatment for streptococcus pyogenes

  • Penicillin
  • Cephalosporins
  • Macrolides
• Streptococcus Agalactiae


  Group B beta-hemolytic and can hydrolyze sodium hippurate and give positive response in CAMP
• Chorioamnionitis


  Bacteria ascends from the vagina into the uterus
• Cystitis


  Bacteria infects the urethra
• Neonatal pneumonia


  Enters the respiratory tract during natural delivery
• Neonatal meningitis


  Passes through the BBB
• Septic Arthritis


  Bacteria infects joints of the newborn
• Treatment for Streptococcus Agalactiae

  • Penicillin G and Ampicilline
  • Cefazolin and Vancomycin (for resistance strains)
• Streptococcus gallolyticus - S. bovis


  Group D alpha hemolytic that is associated with colon cancer
• Enterococcus faecalis and E. faecium


  Group D alpha and gamma hemolytic that colonizes the gut of humans and animals; 2nd most common cause of infective endocarditis
• Viridans streptococci


  Alpha hemolytic with no Lancefield classification and causative agent of dental carries
• S. mutans and S. mitis


  Form aggregates causing dental plaques
• S. sanguinis


  Inhibit the growth of S. mutans
• S. intermedius (S. anginosus group)


  Does not cause bacterial endocarditis but adheres to other organs causing abscesses
• S. viridans


  causes subacute bacterial endocarditis
• S. aureus


  causes acute bacterial endocarditis
• Treatment for Viridans streptococci

  • Penicillin G
  • Ampicillin
  • Cephalosporins
  • Vancomycin
  • Linezolid
• Streptococcus pneumoniae


  No Lancefield antigen, alpha hemolytic, and most common cause of community-acquired pneumonia
• Pneumococcal surface protein A (PsPA)


  responsible for inhibiting the complement

  system
• Rhinosinusitis


  infects the mucus membranes of the nose and the paranasal sinuses
• Otitis media


  Inflammation of the middle ear due to an infection of the eustachian tube
• Pneumonia


  release Pneumolysin causing destruction of the pneumocytes
• Bacteremia


  crosses the blood-alveolar barrier into the circulating blood
• Pneumococcal polysaccharide vaccine (PPV 23)

  • Contains 23 purified capsular antigens
  • Mostly recommended in adults