Streptoccocci Pyogene & infections on surface Flashcards
what is acute Rheumatic fever?
inflammation of the heart, joints, CNS
name the virulence factor that r somatic (part of the organism) and the exotoxins of Strep. Pyrogene
somatic
- caspsule
- LTA lipotechoic acid
- Fibro nectin binding
- M protein
what do the virulence factores of stepp pyogenes cause?
M proteins» destroys complement proetein» prevents phagocytosis
Exotoxins» superantigens» formation of toxic shock symfrome due to activation of T cells.
who is at higher risk of getting the bacteria? and why?
children 5-15 yrs
Remember the M proteins r produced as an antibody response..
basically, the more exposure u had in ur life, the more antibodies u have and the more protection u have against different strains in strep progenes.
BUT KIDS…
ur immunologically naive, u haveent been exposed much, yet u don’t have much antibodies.
List the clinical features u see in streptococcal pharyngitis
- sore throat
- malaise, fever, headache.
- lymphoid hyperplasia
- exaudates of pus over the tonsils
- looks like tonsils have taken over ur mouth!
what happens to those patients who r left untreated?
they tend to develop antibodies to the M proteins! (yay!)
how is strep pyogene spread?
- direct person to person
- (droplets) so u have to be quite near to each other.
- nuresery schools
- prisons
what r some complications of streptococcal pharyngitis?
-Acute rheumatic fever
-Acute Glomerulonephritis
inflammation of renal glomerulus
why does rheumatic heart fever arise from pharyngits?
**bc of the very rich LYMPHOID tissue around the pharynx,
this is important to know bc ARF only follows infection according to certain rheumatogenic M types
what r the 3 complication categories that arise from Strepp. pyogene?
TIP
T> toxic
- scarlet fever
- toxic shock like syndrome
I> immunological
- RHF
- Glomerulonephritis
P>Pyogenic
- Pharyngitis
- cellulitis
- impetigo
explain the pyogenic complication that this bacteria can cause? (4)
can cause SKIN infection like:
-Impetigo
very superficial childhood skin infection
No ARF but is common cause of glomerulonephritis
-erysipelas (dohas disease)
Dermis infection (more deeper than impetigo)
face and lower limbs
raised edged btw affected and unaffected skin
pinkish hot colour
-Cellulitis
skin and subcutaneous tissue infection
seen in patients w/ impaired lymphatic drainage
-necrotising fasciitis
infection of DEEPER subcutaneous tissues and fascia
rapid, extensive necrosis
SEVERE PAIN, even before gross image appears
High fever
what is meant by fulminant course? give and example
the disease progresses from Mins to hrs
necrotising fasciitis
what is necrotising fasciitis
infection of DEEPER subcutaneous tissues and fascia
rapid, extensive necrosis
SEVERE PAIN, even before gross image appears
High fever
Looks like cottage cheese
explain the Toxic complication that this bacteria can cause? (4) and which virulence factor led to it?
Severe drop in BP due to entry of strep A into deeper tissues and BS.»Septic shock
**pyrogenic exotoxins» they have super antigenic activity, they bind further down on a non specific area on T cells! this causes colonial proliferation of T cells! which promoted the release of various cytokines» immune system lights up»
explain the pathogenesis of streptococcal toxic shock syndrome
the M cells strip of the bacteria, and goes and bind with fibrinogen forming a “M protein-fibrinogen Aggregate”.
this complex will go and bind to NEUTROPHILS!!!
neutrophils will stick to the epithelium and DEGRANULATE, releasing lots of hydrolytic enzymes & producing a respiratory burst!
this underlying damage to the endothelium leads to vascular leakage and hypercoagubiltiy!» LOW BP»coagulation» ORGAN DAMAGE
what is rheumatic fever?
serious complication that can develop following an untreated throat infection (by a type of bacteria called group A streptococcus).
occurs 10-14 days after patient has developed infection and sore throat
symptoms of acute rheumatic fever?
J❤️NES
J>joints ❤️~carditis N~Nodules E~Erythemea S~Sydenham chorea
group B strep is S, Agalactiae
its a cause of NEONATOL SEPSIS and meningitis
-its normal flora in the vagina
when baby come out of mama, it is smeared with that bacteria, and those can get into the baby’s BS and cause sepsis.
sometimes the baby can come out already SEPTIC
bc they could have been a rupture in th emenrane a done ht bacteria got into the amniotic fluid
***GROUP B» for BABIES
name types of Streptococci
S Pyrogene»_space; A
S-Agalactiae»B
S- Dysgalactiae»C
S pneumonia
**strep milleri smells like CARAMEL
goo way for diagnosing