Bordetella and Haemophilus Flashcards
1
Q
H flu bacteriology
A
- small, gram neg, pleomorphic rod
- nonmotile
- non spore forming
- grows on lab media with X and V (heme and NAD)- extracts from RBCs- blood loving
- human restricted
- transmitted by respiratory droplets or direct contact
- encapsulated and unencapsulated forms
2
Q
h flu bacteriology 2
A
- high pathogenicity strains have capsule
- 6 serotypes with capsules, type B (Hib) is most severe and causes meningitis, pneumonia, septic arthritis
- Hib capsule of polyribosyl ribitol phosphate (PRP) is target of vaccine
- unencapsulated strains (NTHi) cause local mucosal infections, can spread if untreated, not covered by vaccine
- asymptomatic carrier of Hib is rare, NTHi cp,,pm
3
Q
Hib pathogenesis
A
- colonization facilitated by IgA protease- clears IgA from resp mucosa
- once established, invades blood
- magnitude and duration of bacteremia determine severity of illness**
- meningitis-unvax/untreated mortality is 90%
- 50% of survivors have neuro sequelae
4
Q
Hib pathogenesis 2
A
- host defense is complement and anti-capsule antibody
- vaccination against capsule blocks and reverses infection at early bacteremic stage
- most infections in kids 6 mo- 6years
- maternal antibody wanes, kids can’t raise response
- disease may recur until effective memory response (5yo)
- rare in patients over 6 unless immunocompromised
5
Q
NTHi pathogenesis
A
- lacks capsule, but still has pili, attachment proteins, IgA protease
- pneumonia with biofilm formation in CF patients
- pneumonia, septic arthritis after untreated mucosal infection
- neonatal sepsis, maternal sepsis after vaginal delivery if NTHi normal flora
6
Q
Hib meningitis exam
A
- rapid onset fever, AMS, HA, stiff neck
- may be lethal in hours in infants
- LP for CSF culture and gram stain
- CT for subdural effusion if not responsive to antibiotics
7
Q
Hib cellulitis exam
A
- raised, indurated, tender area on head or nec
- needle aspirate for culture and gram
- may affect eyes, CT if it does
8
Q
Hib otitis media, sinusitis exam
A
-pain and swelling, bulging tympanic membrane
9
Q
Hib epiglottitis exam
A
- swollen, cherry red epiglottis
- progressive respiratory difficulty
- inability to swallow
- lateral neck radiograph once airway is secured
10
Q
Hib septic arthritis
A
- single large, red, angry joint
- side note- can also cause sepsis, pneumonia, pericarditis
11
Q
NTHi exam in neonates
A
- biotype 4
- associated with premies, premature rupture of membranes, low birth weight, maternal chorioamniotis
- presentation within 24 hours of birth
- vertically acquired
- nonspecific symptoms- bacteremia, sepsis, meningitis, pneumonia, conjunctivitis, cellulitis
12
Q
NTHi exam post partum mom
A
- sepsis with endometritis, tubo-ovarian abscess, chronic salpingitis
- take laproscopic fluid samples for culture and gram
13
Q
NTHi complications from local infection
A
- begins with mucosal infection of ear, eye, sinuses, bronchioles
- may cause invasive disease similar to Hib in combination with predisposing conditions:
- advanced age, alcoholism, malignancy, CF, asthma
14
Q
H flu lab diagnosis
A
- gram stain and culture relevant body fluids
- culture on chocolate (heated-blood) agar with and without factors X and V
- growth only with factors usually suffices for diagnosis
- proceed with antimicrobial sensitivity testing
- bio/immuno tests for typying- immune tests for capsule will still be positive after antibiotics begin
- septic arthritis- elevated sed rate and CRP
15
Q
H flu CSF with meningitis
A
- neutrophils
- decreased glucose
- increased protein
- capsular antigen
- positive gram stain
