Aerobic Gram Neg CoccoBaccilli

Question 1

Is haemophilus normal flora?

Answer 1

Yes.

75% healthy children and adults have haemophilus in nasopharynx.

Question 2

What are the (3) growth requirements of haemophilus?

Answer 2

1. Heme (of hemoglobin)
2. Factor X, aka hemin (product of heme oxidation)
3. Factor V (NAD or NADP)

Question 3

Why is the bacteria haemophilus influenzae named after influenza?

Answer 3

It is normally a secondary (opportunistic) infection, and when it was discovered, it was thought to be the cause of the flu (later it was understood to be a secondary infection to the flu virus)

Question 4

What is Hib?
Does it have a capsule?
What (3) illnesses does it cause?

Answer 4

Haemophilus influenzae type b

It is encapsulated

Hib causes:

• meningitis
• epiglotittis
• bacteremia

Question 5

Children tend to survive meningitis with antibiotic treatment, so why do we need to vaccinate against Hib meningitis?

Answer 5

Sequelae: abnormalities resulting from previous disease:

• hearing loss
• mental retardation

Question 6

What happens in epiglottitis? Why is it dangerous?

Answer 6

Swelling of the epiglottis, which can be life threatening if it obstructs the airway.

Question 7

When does Hib tend to cause pneumonia?

Answer 7

In debilitated or immunocompromised adults

Question 8

Why can you culture Hib or any of the other haemophilus bacteria on a regular blood agar plate only if you add S.aureus?

Answer 8

Because S.aureus is type-B hemolytic and lyses the RBCs, making their contents (Factor X and Factor V) available to the haemophilus, which cannot lyse RBCs by themselves.

Because haemophilus cannot lyse RBC’s, they require chocolate agar plates to culture.

Question 9

Who needs to be vaccinated against Hib?

Answer 9

Children under 5

Maybe the immunocompromised