Haemophilus Species & Moraxella Catarrhalis

Question 1

What is PAGE?

Answer 1

• polyacrylamide gel electrophoresis.
• used to identify outer membrane proteins (on Gm- bacteria?)

Question 2

What portion of the H. Flu type B capsule is used in the HIB vaccine?

Answer 2

-polyribosyl ribitol phosphate

Question 3

What is lipooligosaccharide (LOS)?

Answer 3

• present in H. influenzae
• like LPS, but much shorter side chain
• damages tissues and stimulates inflammatory response

Question 4

H. Flu requires X factor to grow. What is X factor?

Answer 4

• hematin, released by lysed RBC’s
• present in chocolate agar

Question 5

How is chocolate agar made?

Answer 5

-by heating blood

Question 6

H. Flu requires V factor to grow. What is V factor?

Answer 6

• NAD⁺ (nicotinamide adenine dinucleotide)
• diffuses from RBC’s -present in chocolate agar

Question 7

How are H. parainfluenzae and H. Influenzae different in their agar growth requirements?

Answer 7

• parainfluenzae needs only V factor, and can grow on blood agar.
• influenzae grows only on chocolate agar and also needs X factor

Question 8

What exotoxins are produced by H. influenzae?

Answer 8

• none recognized
• LOS causes inflammation and damages tissues though

Question 9

How does HITB cause meningitis?

Answer 9

• directly enters CNA via veins or lymphatics
• hematogenously, settling in choroid plexus

Question 10

What is polyribosyl phosphate?

Answer 10

• located in HITB capsule
• causes high level of resistance to phagocytosis

Question 11

What is the host immune response to H. influenza type B?

Answer 11

• Antibody to PRP capsule opsonizes for phagocytosis & is bactericidal
• antibodies to LOS and outer membrane proteins are bactericidal to a lesser extent

Question 12

What is the host immune response to NTHI?

Answer 12

• children who develop otitis initially lack IgG to outer proteins, but develop it
• some antibodies are protective

Question 13

What is “exacerbation of COPD?”

Answer 13

1 NTHI

-tracheobronchitis and pneumonia in persons with pre-existing chronic lung disease

Question 14

What two factors are present in chocolate agar that allows H. Influenzae to grow?

Answer 14

• X factor (Hematin)
• V factor (NAD⁺)

Question 15

What give HITB high resistance to phagocytosis?

Answer 15

-polyribosyl phosphate located in its capsule

Question 16

What indicates a highly virulent organism?

Answer 16

• high proportion of colonizations invade
• a high proportion of those who are infected have serious disease

Question 17

What is puerperal fever?

Answer 17

• infection during birth causing fever
• from organisms in vagina

Question 18

What diseases are caused by Haemophilus Influenza Type B (HITB)?

Answer 18

1. Mningitis
2. Acute Epiglottitis
3. Septic Arthritis
4. Sepsis
5. Otitis media

Question 19

Who is at risk for sepsis caused by HITB?

Answer 19

Children with abent or non-functioning spleens (sickle cell)

*HITB is encapsulated

Question 20

How do we treat HITB?

Answer 20

For serious infections = 3dr generation cephalosporin

Otitis media = ampicillin/amoxicillin

Question 21

What disease is caused by H. influenza biogroup aegyptius?

Answer 21

-Brazilian hemorrhagic fever (epidemic)

Question 22

“cherry red epiglottis”

Answer 22

HITB epiglottitis

Question 23

Where does HITB colonize?

Answer 23

Nasopharynx

Question 24

What disease is caused by Haemophilus ducreyi?

Answer 24

-Chancroid

=venerial ulcers

Question 25

How do we tell apart ulcers that are caused by H. ducreyi vs. T. pallidum (syphilis)?

Answer 25

Syphilis ulcers are not painful, ducreyi chancroids are

Question 26

Rank in order of virulence: Moraxella, NTHI, HITB, H. parainfluenzae

Answer 26

HITB >> NTHI > Moraxella > H. parainfluenzae

Question 27

What diseases are caused by Moraxella catarrhalis?

Answer 27

2 exacerbation of COPD

Question 28

What is the most common cause of exacerbation of COPD?

Answer 28

Non-typable H. influenza

Question 29

How is H. influenza transmitted?

Answer 29

aerosolized