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
**the bicuspid AORTIC valve is associated with INFECTIVE ENDOCARDITIS
why is this so?
The structural abnormality and abnormal tissue provides a place for bacteria to stick and form a colony
What is the hallmark of infective endocarditis?
Formation of VEGETATION that binds to valves or mural endocardium.
Abbarent flow predisposes to a collection of fibrin, platelets, and scant inflammatroy cells.
Microorganisms bind to this & cause local infection.
What is vegetation?
a vegetation is an abnormal growth named for its similarity to natural vegetation. Vegetations are often associated with endocarditis
Decribe consequences of a vegetation seen on infective endocarditis?
- The vegetation has feautres of a biofilm, the bacteria seen there r difficult to eradicate.
- 🥃 It is hard for antibiotics to penetrate there.
What type of bacteria is C difficile?
Gram + rod
What is a heart murmura.
Sound of blood flow turbulence in the heart
What is coagulase?
A enzyme that causes a clot to form when bacteria are incubated with plasma
What is coagulase test
Used to describe coagulase negative bacteria
Used to differentiate btw staph. aureus ( coagulase + ) from coGulase- negative staph)
What is the most common and important of the coagulase negative staphylococci?
Staphylococcus epidermis
Where are coagulase negative staphylococci normally found?
Normal flora of skin
what is a biofilm
extracellular mucopolysaccharide substance produced by bacteria “slime” to shield it form neutrophils, antibiotics and antibodies.
what is plantonik bacteria?
free floating bacteria
explain the formation of biolfilm
ur notes alaa
Name some examples of skin commensals
Virus
- herpes
- papilloma
Gram +
- staph aureus
- Coagulase (- ) strep
- corynebacterium
Gram -
-enterobacteria
Fungi
- yeasts
- dermatophytes
Parasites
-mites
what r dermatophytes?
> > fungi cause superficial skin infections ATHLETES FOOT
teyre important bc they grow around the toes..they can cause little cracks on the skin around the toes.
and if have other bacteria around that area. those cracks can act as a PORTAL OF ENTRY FOR THEM.
name bacteria on mucosal surfaces.
Eye, nose, nasopharynx, mouth, stomach, intestine, urethra, vagina
table in lecture.
what bacteria is the patient who did a cataract surgery most prone to be getting?
coagulase negative staph
which bacteria is normally present in our nose?
staph aureus,
what bacteria should u be aware of before u give a pateint cardiac surgery? (hint nose) and so what should u do before approaching the surgery?
staph aureus up the nose,
distance btw ur nose and the surgical wound area is short, and if cough or sneeze u can contaminate a surgical wound around the chest with staph aureus!
give nasal antibiotic ointment to get rid of them.
what is the relation with bacteria in mouth and endocarditis?
if u brush teeth or whatevs, bacteria can get into blood stream and infect heart!
which bacteria can cause peptic ulcer disease?
h. pylori
Where does MRSA mostly colonize?
Nose
(Also axilla and groin)
(Respiratory tract & urinary tract
Describe strep. Pnemonia
Gram + coccus that gows in chains commonly found in pairs
How do u treat MRSA infections? Why
Vancomyocin» Intravenously
bc MRSA is usually resistent to
- beta lactam antibiotics
- Quinolones
What is pharyngitis
Pharyngitis is inflammation of the back of the throat, known as the pharynx.[1] It typically results in a sore throat and fever.
What is function of M protein on strepp.pyogene?
Resists phagocytosis by inhbiting activation of complement pathway on bacterial surface
U have different sterotypes of it!
Function of streptokinase?
Break down of clots
Used for ppl woth strokes
Function ofstreptococcoal pyrogenic exotoxins?
Memebrof superantigenjc family, (clonal T-cell proliferatoon)
Causing toxic shock syndrom
classify strep pyrogene
group A (beta haemolytic)
what r the complication of pharyngitis?
u can get an peritonsilar Abcess in the tonsil. and behind the tonsil there is the LATERAL PHARYNGEAL SPACE. if the pus breaks off from the tonsil and gets into this space, it can either spread upwards or downwards» mediastinitis, thrombosis in carotid artery, meningitis and brain abcess
!) acute rheumatic fever
2) acute post streptococcal glomerulonephritis
What makes biofilms resist antibiotics
They are in low metabolic state: bcuz antibiotics target only actively multiplying bacteria, therfore hey wont target the slow biofilms
Secondly they form small colony varients SCV
