Haemophilus & Moraxella Flashcards
What is PAGE?
- polyacrylamide gel electrophoresis.
- used to identify outer membrane proteins (on Gm- bacteria?)
What portion of the H. Flu type B capsule is used in the HIB vaccine?
-polyribosyl ribitol phosphate
What is lipooligosaccharide (LOS)?
- present in H. influenzae
- like LPS, but much shorter side chain
- damages tissues and stimulates inflammatory response
H. Flu requires X factor to grow. What is X factor?
- hematin, released by lysed RBC’s
- present in chocolate agar
How is chocolate agar made?
-by heating blood
H. Flu requires V factor to grow. What is V factor?
- NAD+ (nicotinamide adenine dinucleotide)
- diffuses from RBC’s -present in chocolate agar
How are H. parainfluenzae and H. Influenzae different in their agar growth requirements?
- parainfluenzae needs only V factor, and can grow on blood agar.
- influenzae grows only on chocolate agar and also needs X factor
What exotoxins are produced by H. influenzae?
- none recognized
- LOS causes inflammation and damages tissues though
How does HITB cause meningitis?
- directly enters CNA via veins or lymphatics
- hematogenously, settling in choroid plexus
What is polyribosyl phosphate?
- located in HITB capsule
- causes high level of resistance to phagocytosis
What is the host immune response to H. influenza type B?
- Antibody to PRP capsule opsonizes for phagocytosis & is bactericidal
- antibodies to LOS and outer membrane proteins are bactericidal to a lesser extent
What is the host immune response to NTHI?
- children who develop otitis initially lack IgG to outer proteins, but develop it
- some antibodies are protective
What is “exacerbation of COPD?”
1 NTHI
-tracheobronchitis and pneumonia in persons with pre-existing chronic lung disease
What two factors are present in chocolate agar that allows H. Influenzae to grow?
- X factor (Hematin)
- V factor (NAD+)
What give HITB high resistance to phagocytosis?
-polyribosyl phosphate located in its capsule
What indicates a highly virulent organism?
- high proportion of colonizations invade
- a high proportion of those who are infected have serious disease
What is puerperal fever?
- infection during birth causing fever
- from organisms in vagina
What diseases are caused by Haemophilus Influenza Type B (HITB)?
- Mningitis
- Acute Epiglottitis
- Septic Arthritis
- Sepsis
- Otitis media
Who is at risk for sepsis caused by HITB?
Children with abent or non-functioning spleens (sickle cell)
*HITB is encapsulated
How do we treat HITB?
For serious infections = 3dr generation cephalosporin
Otitis media = ampicillin/amoxicillin
What disease is caused by H. influenza biogroup aegyptius?
-Brazilian hemorrhagic fever (epidemic)
“cherry red epiglottis”
HITB epiglottitis
Where does HITB colonize?
Nasopharynx
What disease is caused by Haemophilus ducreyi?
-Chancroid
=venerial ulcers
