Haemophilus Species

Question 1

Haemophilus species are gram _____.

Answer 1

Gram negative coccobacilli

Question 2

Are Haemophilus motile or non-motile?

Answer 2

Non-motile.

Question 3

What about the five species of Haemophilus?

Answer 3

H. influenza
H. haemolyticus 
H. parainfluenzae
H. aphrophilus
H. ducreyi

Question 4

What species of Haemophilus required factor X AND favor V?

Answer 4

H. influenza and H. haemolyticus

Question 5

What is the difference between Haemophilus influenza and Haemophilus haemolyticus?

Answer 5

Both required Factor X and V; however H. haemolyticus can produce beta hemolysis on Horse Blood, while H. influenza does not.

Question 6

What species of Haemophilus exhibit Beta-hemolysis on Horse blood?

Answer 6

Haemophilus haemolyticus

Question 7

What species of Haemophilus have the ability the convert ALA to Protoporphyrin?

Answer 7

Haemophilus parainfluenzae and Haemophilus aphrophilus

The ability to convert ALA to Protoporphyrin means that the organism does not required factor X to grow. So they synthesize it on their own using this pathway.

Question 8

Which Haemophilus species require Factor V (NAD) to grow?

Answer 8

Haemophilus influenza (needs X and V) 
Haemophilus haemolyticus (needs X and V) 
Haemophilus parainfluenzae (needs factor V but not X)

Question 9

Which species of Haemophilus is a member of HACEK and therefore associated with endocarditis?

Answer 9

Haemophilus aphrophilus

Question 10

Which species of Haemophilus is associated with STD chancroids which results in genital ulcers and swollen lymph nodes/buboes?

Answer 10

Haemophilus ducreyi

Question 11

Which species of Haemophilus is associated with Pink Eye?

Answer 11

Haemophilus influenza subgroup aegyptius

Question 12

Why do Haemophilus NOT grow on Sheep Blood Agar?

Answer 12

Sheep blood agar contains NADase, which inactivates NAD (factor V).

Question 13

What can Haemophilus species grow on?

Answer 13

Chocolate agar; supplies both X and V factors. (10%CO2)

Can grow on horse or rabbit blood agar.

Question 14

This species of Haemophilus may produce beta lactamase, which makes them resistant to _______.

Answer 14

Some Haemophilus influenza produce beta lactamase, which make them resistant to Penicillin and Ampicillin

Question 15

What virulence factor is produced by some Haemophilus influenza that make them resistant to penicillin and ampicillin?

Answer 15

Beta lactamase

Question 16

What Haemophilus can cause meningitis in children?

Answer 16

Haemophilus influenza type b (Hib)

Question 17

What can be given to children to combat Haemophilus influenza type B meningitis infection in children?

Answer 17

Hib vaccine

Question 18

What is the satelliting phenomenon?

Answer 18

Haemophilus can grow really close “satelliting” Staph aureus on Sheep Blood Agar (Haemophilus usually cannot grow on sheep blood agar)

Staphylococcus aureus produces NAD (Factor V) as a metabolic byproduct and It also hemolyzes blood cells releasing hemin (Favor X) – therefore due to Factor V and Factor X it is able to grow.