1. ‫بسم ا الرحمن الرحيم‬
GENUS:
HAEMOPHILUS
Prof. Khalifa Sifaw Ghenghesh

2. • Small, Pleomorphic G-ve Rods
• Require Growth Factors
– Two factors > X & V
– X = haemin
– V = Nicotinamide adenine
dinucleotide (NAD)
= NAD phosphate (NADP)
• BA
• Chocolate agar

3. Species
Growth Factor Required
---------------------------------------------H. influenzae
X+V
H. parainfluenzae
V
H. ophrophilus
X
H. ducreyi
X
----------------------------------------------

4. Haemophilus influenzae
• Smooth and rough colonies occur
• Capsulated >>
• Non-capsulated >>

5. ANTIGENIC STRUCTURE
1. The capsular polysaccharide antigens:
• 6 serotypes: a - f.
• Encapsulated H. influenzae >>
Quellung (capsular swelling) reaction.
2. Somatic antigens:

6. VIRULENCE FACTORS
• i. Capsule:
• ii. Outer membrane components:
• OMP & LOS
• iii. Adherence:
• iv. IgA proteases:

7. PATHOGENESIS
• Normal Carriage
– H. influenzae > Human parasite
– Non-capsulate HI > nasopharynx or
throat of 25-80% of healthy people
– Capsulate strains in 5-10%
– Immunization with conjugate vaccine >
• Invasive infections
• Non-Invasive Disease

8. INVASIVE INFECTIONS
H. Influenzae type b
Respiratory portal of entery (Inhalation)
Colonization of nasopharynx
Penetration of submucosa
Invasion of Bloodstream
Meningitis, Epiglottitis, Bacteraemia
Pneumonia, Septic arthritis
Non-Capsulate HI:
> Meningitis and Septicaemia > the Neonate

9. NON-INVASIVE DISEASE
• Local Infections:
– Physiological or Anatomical Abnormalities
– Otitis Media, Sinusitis
– Purulent episodes > patients with
exacerbations of chronic obstructive
airway disease
– Non-capsulate strains of HI
– Viral Infections ?

10. LABORATORY DIAGNOSIS
1. Direct examination:
– Specimen: CSF, middle ear aspirate,
sputum (purulent).
2. Culture:
– Chocolate agar + CO 2
– Blood culture bottles
– Antigenic detection
– Molecular Techniques

11. Blood agar plate culture of
Haemophilus influenzae

12. Haemophilus influenzae satelliting
around Staphylococcus aureus

13. TREATMENT
• - Systemic illness
– 3rd Generation cephalosporins
– TMP-SMZ, Ciprofloxacin, Clarithromycin
• - Otitis media in children
• - Pneumonia in adults
• - Acute sinusitis
– Amoxicillin, Augmentin, Clarithromycin,
PREVENTION
• Vaccination

14. • Haemophilus influenzae biogroup
aegyptius (Haemophilus aegyptius)
– Epidemic conjunctivitis
– Brazillian purpuric fever
• Haemophilus ducreyi> Chancroid
• Haemophilus parainfluenzae