Haemophilus

Question 1

Characteristics of H.Influenzae

Answer 1

Gram Neg Coccobacili
Polysaccharide Capsule (Type B ->Ab protective)
Pili
Endotoxin LPS
Nonmotile
Non sporeforming
Requires Factor X and V in chocolate agar to grow

Question 2

Is there a vaccine for H.Influenzae?

Answer 2

Vaccine for H.flu type B

Polysaccharide conjugated todiphtheria toxoid

Question 3

What does H.Influenzae cause in children

Answer 3

Meningitis, Septicemia, Cellulitis

Question 4

What does H.Influenzae cause in chidlren 2-5 years old?

Answer 4

Epiglottis, pneumonia

Question 5

What is the pathogenesis of H,Influenzae?

Answer 5

Transmission via respiratory droplets -> Adhere via pili/OMPs -> transcytose -> encapsulated and invade blood -> endotoxin -> local and systemic infammation

Question 6

What are hte clinical manifestations of H.Influenza?

Answer 6

Meningitis
Epiglottitis: fever sore throat stridor, cherry red
Cellulitis
Arthritis

Question 7

What are hte clinical manifestations of nontypable H.Influenzae?

Answer 7

Otitis Media
Sinusitis
Bronchitis (Exacerbate COPD)

Question 8

How is H.Influenzae diagnosed?

Answer 8

Gram Stain: CSF, joint fluid
Culture: Chocolate agar
Requires growth factors from blood
Factor X: Hematin (breakdown product of Hb)
Factor V: NAD

Question 9

How is H.Influenzae treated?

Answer 9

Broad Spectrum Cephalosporin for severe

Less Severe(Sinusitis, Otitis Media): Amoxicillin/Clavulanate, Trimethoprim-Sulfamethoxazole, Fluoroquinolones

25-50% produce B-lactamase => Ampicillin resistant

Question 10

How is H.Influenzae prevented?

Answer 10

Vaccine for Type B H.Influenza -> universal in children

Prophylaxis: Rifampin