Haemophilus and Pertussis Flashcards
haemophilus morphology
gram neg rod
pleomorphic
non motile
haemophilus is associated with what other disease?
influenza
typeable vs nontypeable
encapsulated vs non encapsulated
what types of disease does encapsulated haemophilus cause?
respiratory infections and bacterial meningitis in kids
sinusitis
ear aches
can progress to:
bacteremia, meningitis, epiglotitits, cellulitis, or joint infections
before Hib vaccine, leading cause of bacterial meningitis in kids
what types of disease does unencapsulated haemophilus cause?
respiratory infections
ear aches
sinusitis
desseminate disease in compromised individual
no meningitis
what are the haemophilus capsule made of
carbohydrates
a-f are important, b is the worst
helps avoid immune system- antiphagocytic and anti-complement
who carries haemophilus
everyone- 75%
where does haemophilus live?
nose, spreads via aerosolied form
is there a haemophilus vaccine?
yes- to the b encapsulated form
vaccine was originally to capsule, more recently conjugated to protein
encapsulated Hi pathogensis
no exotoxins
endotoxins covered by capsule, so only contributes in bacteremia
Hib- LPS covered with choline
encapsulated Hi immunity
passive from mother for a few months
children susceptible from 6-12 months
acquire active immunity at about 3-4 years of age
treatment of Hib infection
for meningitis- 3rd gen cephlosporin or augmentin
low mortality with early treatment
prophylactic rifampin for contacts
nontypeable Hi pathogenesis
causes respiratory and ear infections, conjuctivitis
colonization starts in nasopharynx
kids get ear infections thru shorter eustachian tubes
only causes meningitis in compromised patients
HI adhesins
adhesins found in both types of Hi promote colonization’
so much variability that they arent good vaccine targets
is nonencapsulated Hi intra or extra cellular?
both
vaccines for unencapsulate Hi?
no
treatment for NTHI
treatment for otitis media- amoxicillin (resistant strain has b-lactamase inhibitor added)
Hi growth and metabolism
facultative anaerobe
no diagnostic fermentation
fragile and fastidious
doesnt grow on blood agar- uses chocolate agar
needs X factor- hemin, and v factor- NAD
these growth properties are used to identify
diagnosis of Hib
history/age
culture and blood/csf
presence of type b Ag
bordetella pertussis causes what?
whooping cough
bordetella pertussis morphology
gram negative coccobacillus
bordetella pertussis type of metabolism
obligate aerobe``
bordetella pertussis transmission
aerosol droplets
bordetella pertussis incubation period
7-10 days
