Encapsulated org Flashcards
Disease is associated with which variant of H. influ?
S. pneumo? N. meningitis?
H. influ: Type B in unvaccinated pop
S. pneumo: 12 serotypes
N. meningitis: Type A serogroup
bacterial meningitis colonizes where prior to an epidemic?
Colonizes upper respiratory tract of a sig. proportion of the pop
What were the majority of DEATHS during the influenza pandemic caused by?
Secondary bacteria pneumonia from:
- S. pneumo
- H. influ
- S. pyogenes
- S. aureus
Which organisms are more severe in:
Meningitis
Bacteria Pneumonia
Otitis media (middle ear infxn)
Meningitis:
- S. pneumo> N. meningitis»_space; H. influ
Bacteria Pneumonia:
- S. pneumo > H. influ
Otitis media (middle ear infxn) - S. pneumo > Moraxella > H. influ
Teichoic acids (TA) + Peptidoglycan (PG) + Pneumolysin
enhances production of cytokines –> cytokine storm
Lysis of organism –> inflammation and more serious infxn
Do unencapsulated encapsulated strains of S. pneumo and N. meningitidis cause major disease?
Encapsulated
*unencapsulated strains do cause morbidity but not as high
Coccobacillus
H. influ
Media to grow H influ
Chocolate agar
- needs X (heme) and V (NAD)
Presence of anticapsular ________ in blood stream protects against serious invasive meningitis disease.
IgG or IgM
*person with no anticapsular antibody are at high risk for meningitis
Person with IgA blocking Ab have a high risk for meningitis, even if they have anticapsular ab
Why not immunize children
Respond poorly to T cell independent Ag such as capsular polys
*the protective Ab may come from an immune response normal flora Ag which cross-react (ie: have similar antigenic structure) with the capsules of virulent species
What helps immunize people against H influ type b when they cannot get vaccinated?
Normal flora produce Ag similar to capsule
*but not we have a conjugate vaccine we can give
Who should receive the Hib vaccine in comb with DTap?
CHildren
Why is the pneumonia vaccine a misnomer?
It has efficacy against invasive pneumococcal disease, not against non-bacteremic pneumococcla pneumonia
- not immunogenic in children
Prevnar vaccine
Conjugated vaccine made from 13 capsule types of S. pneumo that are linked to Diphteria toxoid CRM
Haemophilus species that require only Factor X and only Factor V? Which one requires both?
X: H. ducreyi
V: H. parainfluenzae
X+V: H. influenzae
What is a satellite colony? What is an example?
Colonies of bacteria that like to grow near others
ie: H. influ likes to grow near Staphylococci on blood agar
getting their NAD from Staph
GP diplococci vs
GN diplococci
GP diplo: Strep pneumo
GN diplo: N. gonorrhea
Agglutination test
Antibodies to capsules (organisms with specific antigens)
Countercurrent Immunoielectrophoresis
Detects the presence of capsule in bodily fluids
- look for precipitin band
Useful if pt has already been treated with antibiotics bc these organisms shed the capsular polysaccharied where it can be detected (into their urine)
Possible cross reactivity that can occur with:
H. influ
S. pneumo
N. meningitis
H. influ:
- teichoic acids of many GP + nl flora
S. pneumo
- Hu ABO antigens
N. meningitis
- K1 capsule of E. coli & brain gangliosides
What happens if you lyse pneumococcus organisms with a capsule containing TA, PG, + Pneumolysin with autolysin or B-lactam antibiotics?
Release contents –> activates complement, binds Fc portion of Ab, triggers cytokine release –>
Inflammation and tissue damage
PCV13 vs PPSV23 (valent)
PCV13: higher and more sustained response.
Immunocompromised, asplenic, CSF leaks, or cochlear implants should recieve PCV13 first and then PPSV23 6-12 mo later. (low–> stronger)
Or is youre >65, and have already recieved the PPSV23, then get the PCV13 booster 1 year after.
