(VI) Gram Positive Cocci (5)*Streptococcus pyogenes (GAS) Flashcards
Hemolysis: Strep. pyogenes
β
What organism has a capsule made of hyaluronic acid?
Strep. pyogenes
What type of infections does Strep. pyogenes cause?
(1) Pharyngitis/tonsillitis
(2) Impetigo
(3) Cellulitis/Erysipelas
Name 3 signs/symptoms of Scarlett fever
(1) “Strawberry tongue”
(2) Pharyngitis
(3) Diffuse rash sparing the face
Name 2 effects of Strep. pyogenes’ M protein
(1) Anti-phagocytic
(2) ⇒ Abs against mitral valve
Which of Strep. pyogenes’ exotoxins causes necrotizing fasciitis?
SpeB
(“B for Burnt”)
Which of Strep. pyogenes’ exotoxins are superantigens?
(1) SpeA
(2) SpeC
What type of Strep. pyogenes infection precipitates rheumatic fever?
Pharyngitis
What does the JONES criteria stand for?
(1)** J**oints (Polyarthritis)
(2) ♥ - Rheumatic Heart Disease
(3) Nodules
(4) Erythema marginatum
(5) Syndenham’s chorea
What type of Strep. pyogenes infection precipitates post-streptococcal glomerulonephritis?
(1) Pharyngitis
(2) Skin infections
How long does it take for post-streptococcal glomerulonephritis to develop?
~2 weeks
(Contrast with IgA nephropathy which occurs at same time as the pharyngitis)
Which sequelae of a Strep. pyogenes infection is NOT prevented by treatment?
Post-streptococcal glomerulonephritis
(He’s holding the penicillin ∴ being treated, yet he still has facial edema/puffiness. Treatment prevents rheumatic fever)
Name 5 virulence factors of Strep. pyogenes
(1) Hyaluronidase
(2) Streptolysin O
(3) Streptokinase
(4) DNAse
(5) SpeA-C
How can you differentate GAS from GBS?
GAS is Bacitracin sensitive
What lab test can be ordered to check for recent Strep. pyogenes infection?
ASO titer
Desribe the rash of Scarlett fever
Diffuse but spares the face
What are the common clinical presentations of streptococcus pyogenes infection? (IMPT!!!)
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What are the common clinical presentations of streptococcus pyogenes infection? (IMPT!!!)
- Pharyngitis/tonsillitis (local complications: peritonsillar abscess (quinsy), sinusitis, otitis media, mastoiditis, post viral pneumonia)
- Skin & soft tissue infections: Impetigo (restricted to epidermis), erysipelas (palpable border), cellulitis (not distinct border), wound infections
- Exotoxin mediated **Scarlet fever, Streptococcal TSS (toxic shock like syndrome), Necrotizing fascilitis **
- Non-suppurative complications (delayed ab-mediated disesease): Acute Rheumatic Ferver (ARF), Acute GlomeruloNephritis (AGN)
Strep Pyogenes is almost a buzzword for ARF!! Superimpt.
Pathogenesis of ARF is molecular mimicry (cross-reactivity). M proteins from S pyogenes is similar to heart myosin protein –> rheumatic heart disease, predisposes to subacute bacterial endocarditis
