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64 Cards in this Set
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- Back
- 3rd side (hint)
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Lancefield Group A Strep
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S. Pyogenes
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B hemolysis
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Lacefield Group B
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S. Agalactiae
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B hemolysis
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Lancefield Group D
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Enterococcus faecalis
E. Faecium |
Gamma hemolysis
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Morphology of Streptococci
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Gram + cocci in chains, pairs
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Metabolism of Streptococci
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Facultative anaerobe - lactic acid producting via fermentation
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PYR (-)
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S. agalactiae
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a- meaning none
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PYR (+)
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S. pyogenes
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Pyo is PYR Positive
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Test to differentiate Group A and B Streptococci
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PYR; A is positive
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Types of strep colonies (both colorless)
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Mucoid - capsule with hyaluronic acid in group A
Matte - dried capsuless with less virulent activity |
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Strep catalase test
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ALL negative
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all Staph are catalase positive
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Lancefield Classification based upon
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antigenic grouping base on C carbohydrate of cell wall (A to V known)
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Bacitracin sensitive
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Group A Strep only
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Hemolytic activity types
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B, A, Gamma (in order of hemolysin activity)
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Main antiphagocytic structure of streptococci
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M protein; > 63 antigenic types
this binds Factor H which is anticomplement |
used for typing bacteria (>63 types)
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Postinfectious sequelae
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Acute poststreptococcal GN
Acute rheumatic fever |
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Streptolysin O
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detected by ASO titer in serum
- this lysis RBCs and WBCs |
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Streptokinase
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degrades fibrin
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Streptodornase
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degrades DNA; ADB titer
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hyaluronidase
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helps augment strep invade hyluronidase (and degrades own capsule!)
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Cuases scarlet fever
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Pyrogenic exotoxin: erythrogenic toxin
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gene for this is not in the bacterial genome but is PHAGE MEDIATED
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c5a peptidase
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inhibits chemotaxis
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proteases of group A strep
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aids invasion
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Reason for invasiveness of Group A Streptococci
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large amount and variety of extracellular proteins that aid in invasion
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Types of group A strep invasions
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1) superficial
2) invasive 3) post-infectious sequelae |
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Types of epithelial group A infections
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pharyngitis (strep throat) and impetigo
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Dx of strep throat
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throat culture
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strawberry tongue
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Scarlet fever; group A strep
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group A antigen or diagnosis by throat culture
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Impetigo
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crusty, honey-colored lesions with BLISTERS = strep pyogenes
without blisters = staph aureus |
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child bed fever
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Puerperal sepsis (obstetrical infection) caused by group A strep
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cellulitis
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erysipelas caused by group A strep
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WARM, dermarcated
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flesh-eating virus
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Necrotizing fasciits caused by group A strep ( can be secondary to cellulitis)
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Acute poststreptococcal GN occurs after what
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impetigo or pharyngitis
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Type III immune deposition disease
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Symptoms of acute post-strep GN
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hematuria, edema, HTN
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treatment of accute post-strep GN
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supportive care
- prophylactically with penicillin |
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Cause of acute rhematic fever
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immune-mediated idiopathic ONLY AFTER pharyngitis (strep A)
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symptoms of acute rhematic fever
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arthritis, chronic carditis, Sydenham's chorea
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Group B strep
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S. agalactiae
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Test for Group B strep
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CAMP test
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Diseases caused by Group B strep
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B for Babies and Birth canal;
neonatal sepsis and meningitis and maternal obstetric infection |
Staph aureus with Strep agalactiae (Staph a with Strep a)
special for gram + cocci |
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Strep in normal flora of GU.
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S agalactiae
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#1 cause of neonatal meningitis
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S. agalactiae
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#1 cause of neonatal sepsis
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S. agalactiae
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Group D streptococci
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Enterococcus and Strep. bovis
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Normal GI flora
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Enterococcus
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All group D will grow in what medium?
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bile esculin
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All enterococci can grow in what medium?
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6.5% NaCl
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Single organisms in UTI and SBE (subacute bacterial endocarditis) and peritoneal cavity infections
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Group D Streptococci
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Enterococcus faecalis
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Treatment for Group B strep
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penicillin
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Treatment for group D strep
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ampicillin + gentamicin
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hemolytic activity of enterococcus
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gamma hemolytic
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Viridans streptococci belong in what group?
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no Lancefield group
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most abundant streptococci in mouth
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viridans streptococci
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hemolytic activity of viridans streptococci
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alpha hemolytic
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laboratory identification of alpha hemolytic strep that is not strep pneumonia
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Viridans streptococci
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Dental caries result from which strep and how?
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lactic acid production by viridans streptococci
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treatment of viridans streptococci
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penicillins
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Virulence of S. pneumoniae
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large, antiphagocytic capsule
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avirulent pneumoniae have no what?
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capsule (they are "R-mutants")
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quelling reaction +
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Streptococcus pneumoniae
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capsule swells with Ab
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antigen common to all S. Pneumoniae
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C antigen; target of CRP
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Positive lab tests for pneumococci
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MOBI
Mouse virulence Optochin Bile soluable Inulin fermentation |
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Diseases caused by pneumococci
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POMS
pneumonia Otitis media Meningitis Sepsis |
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Reasons why pneumococci, a normal human flora, cause disease
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sub-normal conditions ( abnormalities of respiratory tract, alcohol/drugs, clearance defects)
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Immunization of pneumococci is by what?
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immunogens made by capsularp olysaccharides
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