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13 Cards in this Set
- Front
- Back
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Group A Streptococcus = Streptococcus pyogenes
Tests |
Gram positive (chains)
Catalase negative B hemolysis PYR positive (pink to cherry red on cotton ball) Bacitracin susceptible (a disk) Facultative, capnophilic Fastidious Streptolysis O (SLO) and/or DNAse B |
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Streptococcus pyogenes
Viruelence |
M protein (adhesin, degrades complement, 120 serotypes, similar to cardiac myocyte)
Capsule Lipoteichoic acid (adhesin) M-like protein (binds IgG and IgM) F protein (adhesin-> internalization) Erythrogenic toxin Super antigen (SpeA, SpeC) |
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Streptococcus pyogenes
Diseases |
Pharyngitis (5-15 yrs old) peaks in winter may lead to Ruematic Fever-antibiotic prophylaxis or Acute Glomerulonephritis-no antibiotic prophylaxis
Impetigo/Pyoderma (summer, children, minor trauma. vesicle->pustule->ruptures and crusts over, painless, ) Scarlet Fever (spreads through blood to localize in skin. palms and soles spared. strawberry tongue. desquamation) Erysipelas (butterfly rash) Cellulitis (from trauma, surgical wound, or insect bite) Necrotizing fasciitis (starts like cellulitis, obstructed blood supply causes necrosis) Toxic Shock Syndrome (bacteremic unlike staph-TSS) |
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Streptococcus agalactiae (Group B Strep)
Tests |
Gram positive (long chains)
Catalase negative Facultative B-hemolyic Resistant to bacitracin (a disk) CAMP test positive (synergistic hemolysis with Staph aureus) |
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Streptococcus agalactiae
Virulence |
Nine capsular polysaccharide types (Ia, Ib, II-VIII)
Ia, III, V most commonly associated with disease |
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Streptococcus agalactiae
Diseases |
Vaginal colonization -> premature birth -> greater disease risk for infants
Bacteremia Pneumonia bone/skin/soft tissue infections UTI near pregnancy-> chorioamnionitis puerperal sepsis In newborn bacteremia, pneumonia, #1 cause of meningitis |
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Streptococcus pneumoniae (one of the viridans streptococci)
Tests |
Gram positive (pairs of lancet shaped cocci)
Fastidious capnophilic Alpha-hemolysis (mucoid) Bile salt susceptible (Opposite other viridans) Catalase negative Optochin sensitive (p disk) (Opposite other viridans) Teichoic acid in urine (sensitivity: 70% bacteremias, 100% in CSF) |
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Streptococcus pneumoniae
Virulence |
Capsule (main virulence factor, >90 serotypes)
sIgA protease Pneumolysin (Ply) (kills ciliated epithelial cells) |
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Streptococcus pneumoniae
Diseases |
Mostly endogenous spread
A major cause of Otitis Media (with pain and fever) Pneumonia (often preceded by virus, acute, rusty sputum, affects only one section/lobe "lobar consolidation") Sinusitis (most often a virus, but when acute = bacteria) Meningitis (most common cause of meningitis in US, very fatal, severe neurological defects) |
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Enterococcus (E. faecalis, E. faecium)
Tests |
Gram positive (pairs and chains, lancet shaped)
Resistant to temperature (up to 45 degrees Celcius) Resistant to high bile salt Resistant to antibiotics Optochin resistant (p disk) White colonies on blood agar, non hemolytic |
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Enterococcus (E. faecalis, E. faecium)
Virulence |
highly resistant to antibiotics and environment
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Enterococcus (E. faecalis, E. faecium)
Diseases |
UTI (common with indwelling catheters)
Peritonitis Endocarditis (with persistent bacteremia) |
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Anaerobic Cocci (peptostreptococcus)
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Cause problems when normal flora enters otherwise sterile areas. no testing necessary except for determining anaerobic coccus.
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