25- H Infleunzae Flashcards
Are they always gram - cocci
No can be filamentous too
Which acute resp infections does it cause
Bronchitis, pneumonia
Which urt major thing can it cause other than sinusitis etc
Epiglottitis
What does it cause mainly in children 3-3 years old
Meningitis/ inflammation of the meninges
Can it be seen in healthy
Yes as an opportunist
What does it need to grow in and why
Blood agar for factor x and v
What is fsctor x
Haemin- it’s required for cytochrome c and fe enzymes of the bacteria
What is factor v
Nad / nad phosphate needed for oxidation reduction processea
Does it need co2
No but there is a 5-10% increase in growth
Why is agar usually heated
To release nadases which increases factor v and then heat also allows rbc to release factor x haemin
How is it diagnosed in rare cases
Microscopy or biochemical tests
What is given without diagnosis
Antibiotics to treat general infection
Give examples of some biochemical tests
Catalase positive and oxidase positive
How many types of capsulated hi are there
6- a to f (b most invasive)
Which polymer capsule does b have
Poly ribosyl ribitol phosphate (in the hib vaccine)
How many biotypes are there based on biochemical tests and which most common
8
1-3 most common
Which type is most invasive
Type 1, b hi
There are 2 types of infection. Invasive and non invasive/respiratory. What causes invasive
90% type b, 10% non capsulated , 1% e and f
What are non invasive most common in
90% occurs in children eg meningitis, pneumonia, sepsis
What causes 90% of non invasive in adults and children eg otitis, sinusitis, epiglottitis
Non capulsated
Which other pathogens can cause invasive infection (demuri)
Viral infections
What sort of vaccine is hib
Conjugated to increase TD responses as polysaccharide don’t produce good responses in children
What after vaccine causes meningitis in children
Non capsulated
When would invasive infections occur in adults whcih is v rare eg pneumonia
If immunocomprised or have chronic infections or malignancy
Since adults have good b ab what can cause these rarely
E and o types
Why are neonates below 2 months not at risk of invasive eg meningitis
IgG transfer from placenta against capsules
When does systemic usually occur/ how
Penetration of submucosa after eg disruption like smoking, viral pathogens. Causes transepithelial migration into blood stream ie bacteraemia
Why is capsule of hib important for virulence
Evades phagocytosis and complement mediated lysis
What are the meninges
3 connective layers covering the csf brain and spine
What are the 3 layers
Dura mater (outer)
Arachnoid mater
Pia mater
Why is it more common in children
Small distance between sinuses and bbb/meninges
Where is the csf encased in meninges
The subarachnoid space
What is aseptic meningitis
Meningitis caused by viruses (most common)
Give some characteristics of viral meningitis
More lymphocytes than neutrophils , no glucose reduction and less inflammatory proteins in csf
What do you call bacterial meningitis and some characteristics
Purulent
Causes neutrophil increase, reduced glucose in csf as bacteria use it, also 10x more inflam proteins in csf
What are some symptoms
Rashes, very high fever, neck pain, headaches, lethargy , joint pain
What is the lumbar puncture diagnostic test
Spinal needle inserted into the L3/4 space and collect csf to detect eg levels of inflam cells, protein levels in csf
What is the carriage % in healthy of non capsulated vs capsulated
25-80% non capsulated in nasopharynx vs 5-10% of capsulated
Which environment factors associated with meningitis spread in children mainly
Winter months , low socioeconomic backrounds
What is the mortality rate of meningitis and long term effects
5% other than that can cause neurological disease, seizures, hearing loss sometimes
What % did the hib reduce disease in under 5
By 95%
Due to increases in 1999 what was offered since
Booster to 6months- 4 years of age
Since 2006 what is the conjugate given with
Meningococcus vaccine
Diagnosis is rarely given so what antibiotics given
Ceftriaxone
What is epiglottitis caused by and what age most common (non invasive disease)
1-6 years
Causes by hi b
What shouldn’t be done if suspected epiglottitis
No lying down as it falls over trachea, also don’t inspect throat as can cause spasm closing airways
What are given to stop airway closing/ treatment
Tube inserted and iv antibiotics given and oxygen if low respiratory
What are non type able hi. Nthi
Primarily mucosal pathogen causing resp issues and also things like otitis media
What resp issues do nthi cause
Bronchitis/copd exacerbation
Also bronchiectasis and cf
How do they attack and colonise
Bind mucosa via adhesins/pili and stop ciliary function
How do they evade immune system
Iga proteases, microcolony formation, ag drift
Which invasive system do they have to colonise phagocytes and lung parenchyma
T3ss
What causes the dysbiotic from commensalism to pathogen
Smoking, viruses , aspirations, ag drift/mutations
Why is ceftriaxone given and not penecillin
20% of strains have b lactamase
Which article discusses hi diagnosis and interaction with viruses
Slack 2015
Why are PCR assays /capsular serotyping used instead of horse blood agar to study them more often
Some don’t have haemolytic effects
Which virus is related to nthi exacerbation eg during copd
Rv
How
Can upregulste adhesion proteins on epi cells for invasion eg Icam1 and also impair neutrophil protection from nthi
Which article discusses nthi and copd/airways
Su et Al 2018
What do they upreg which converts it from commensalism
Pathogenicity islands eg for invasion and attachment and iga proteases
What do nthi form during otitis media
Biofilms
What on epi cells which causes integrity is reduced in copd and caused by nthi
E cadherin
Which tlr do they induce during copd and cause inflammation via nfkb
Tlr 2
Why does smoking allow more nthi in things like copd
Impairs the phagocytosis of nthi and the t and B cells against it
Which article talks about haemophilia and meningitis invasion
Hauser et Al 2018
What allows better adherence to cells of resp tract
Fimbriae
How do hib pass through to blood steam if not through cell invasion
Paracellular
How does hib and hif enter brain
Choroid plexus
On what side
Baso lateral side which is side facing the blood stream
Other than evading immune system what does hib and hif capsule allow in blood stream
Rapid replication
How like other capsulated eg neisseria and pneumoniae can they penetrate epi cells much better
By shedding their capsule in resp tract
