This document summarizes information about the genus Haemophilus. It describes their characteristics like being small, pleomorphic, Gram-negative rods that require growth factors. It then lists the different Haemophilus species and their required growth factors. The document focuses on Haemophilus influenzae, describing their antigenic structure, virulence factors, pathogenesis, invasive/non-invasive infections they cause, laboratory diagnosis, treatment and prevention.

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