Studydroid is shutting down on January 1st, 2019

by jdoby

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normal flora in intestines that is catalase neg, gram positive
(E.faecalis, E.faecium)
S.pneumoniae considered normal upper respiratory flora, also leading cause of
bacterial meningitis, pneumonia
Epidemiology of catalase neg, gram positive cocci
S.pyogenes may be found in the upper respiratory tract but rarely considered normal flora
the sole product of glucose fermentation is
lactic acid
some strains have a capsule of hyaluronic acid that makes them indistinguishable from connective tissue
Known virulence factors of streptococcus
M proteins

opacity factor

strep O
strep S
Extracellular toxins
type specific cell surface antigens
opacity vs. M protein

opacity factor increases the virulence of M protein
(still researching how it happens)
strep O

responsible for the beta-hemolysis of Group A

streptolysin S

oxygen stable and actively participates in both A,ANA hemolysis by the group A strep
Streptolysin that may be responsible for destroying WBCs that ingest the Group A strep

Streptolysin S
Virulence factors S.pyogenes extracellular toxins
Responsible for the rash of scarlet fever

toxic shock-like syndrome
Virulence enzymes of S.pyogenes
Hyaluronidase ??
breaks down connective tissue and allows spreading
hydrolyzes fibrin clots and allows for spreading
Group B strep

virulence factor
surface antigens prevent phagocytosis

increase virulence and survival of the organisms

Virulence factor
produces adhesins, an alpha-hemolysin,
pneumolysin, autolysin and pneumococcal surface protein that function in virulence
virulence factor in S.pneumoniae which makes resistant that cause pneumococcal bacteremia and meningitis
polysaccharide capsule
Pneumococcal vaccines are
23 capsular antigens
most common infection is
streptococcal pharyngitis
Strep-throat is
self limiting but treated with antibiotics to prevent secondary infections
strep also cause
skin infections

"flesh-eating bacteria"
non-suppurative complications
most concerning/morbidity
Acute rheumatic fever
Toxic shock like syndrome

secondary infection after pharyngitis
maybe due to the production of antistrep antibodies
Acute Rheumatic fever present with
migratory arthritis
heart murmurs
cardiac enlargement
congestive heart failure
rarely presents with intractable cardiac arrest and death
lab Findings in Acute Rheumatic fever
increased ESR
increased CRP
previous strep infection
increased or rising strep antibody titers
--anti-DNase B
--anti hyaluronidase
Acute glomerulonephritis
SEcondary infection after pharyngeal or skin infection
presents as glomerular inflammaiton with hypertension
hematuria and proteinuria
and RBC Cast
Acute Glomerlonephritis
Antibodies tests for Acute Glomerulonephritis
ASO is unreliable so anti-DNase B or anti-hyaluronidase should be performed
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