Streptococcus
Terms
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Group B Strep
Agalactae -
Can cause neonatal secpticemia, meningitis, or pneumonia
Can have early/late onset (utero, birth or later)
60% of colonized mothers give birth to colonized babies
Blood cultures, swabs, CSF find G+ cocci
Obstetric Complications: UTI's, Peurperal sepsis, Amnionitis, Endometriosis, wound infections - Viridens Streptococci
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S. Salavarius, S. Mitis
Can cause disease when introduced to abnormal heart valves.
Alpha hemolytic
Found in Normal flora of upper respiratory tract
Must be differentiated from S. Pneumnonia - Lactic Streptococci
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Found in milk
Not associated with disease
Strep Lacis
Strep Cremoris - Group D Enterococcus
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Enterococci-Streptococcus Gaecalis
Hemolysis variable (mostly non-hemolytic)
Fibrinolytic
Protein/Carb factors regulate adherance
Bacteriocins: Inhibit competitive bacteria
Found in normal flora of intestinal tract
Common in pyelonephritis, wounds and subacute bacterial endocarditis
Resistant to antibiotics (VRE)
Vancomycin Resistant Enterococcus -Mediated by R-Plasmids
Risk factors: Urinary or intravascular cathertization
Capable of surviving high concentrations of bile and sodium chloride (Grew on MSA)
7
(E. Faecalis colonize large intestine 10
and urinary tract - Beta Hemolytic Strep
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All contain a group specific C-carbohydrate
Serological grouping (lancefields typing)
Group A -S. Pyogens
Group B -S. Algalactae
Group C -Pathogen of animals - Streptolysins
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Streptolysins
*Strep S_Stable/oxygen (hemolysis)
*Strep O-Inactivated by ox.(stab agar)
*Antigenic (ASO titer) Strep marker
*Cardiotoxid & Leukocidal
Streptokinase-
Initiates fibrinolytic dissolution
of fibrin clots.
Hyaluronidase
Depolymerizes connective tissue
Erythrogenic toxin
Local redness/Scarlet fever
M.Protien
Found in cell wall -pilli - Strep Throat
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signs/symptoms: red sore throat, white patches tonsils, swollen lymp nodes in neck, fever, headache (naus/vomit children sometimes)
Transmission: Direct close contact-respiratory droplets (cough/sneeze) Rarely from milk/milk products
Untreated patients most infectious 2-3wks after onset.
Incubation period before symptoms:
2-4 days after exposure
Patient no longer infectious after 24 hrs. of antibiotics
Diagnosis: throat swabbed for culture or rapid strep test (10-20 min) culture usually 24-48 hrs. (neg cult=viral) - Scarlet Fever
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occurs w/sore throat and rarely w/impetego or other strep infections
fever/rash over upper body (may be all)
Rash is fine, red, rough texture and blanches upon pressure
Bright red strawberry tongue
skin can peel after recovery.
Illness spread by same means as strep/treatment same too - Strep Morpholoy and Physiology
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G+ Cocci in chains
Colonies: very small convex / granular
Phys: facultative anaerobes
Fastidious nutritionally
(require blood, AA &nucleic acid
derivatives)
Catalase negative
Is not dissolved in 10% bile salt
ENCAPSULATED
Blood Agar: HEMOLYTIC - Group A _ Strep. Pyogenes
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Bacitracin identifies
Pharyngitis/Strep throat
Scarlet Fever
Skin infections
(Nec. Fa. flesh-eating)
Bactermia, sepsis, strep toxic shock synd,
Complications: Acute Rheumatic Fever
and Poststrep. glomerulitis