Download - Lecture 22 Haemophilus
بسم الله الرحمن الرحيمبسم الله الرحمن الرحيم
GENUS: GENUS: HAEMOPHILUSHAEMOPHILUS
Prof. Khalifa Sifaw Ghenghesh
• 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
Species Growth Factor Required
----------------------------------------------H. influenzae X + VH. parainfluenzae VH. ophrophilus XH. ducreyi X----------------------------------------------
Haemophilus influenzae
• Smooth and rough colonies occurSmooth and rough colonies occur
• Capsulated >>Capsulated >>
• Non-capsulated >>Non-capsulated >>
ANTIGENIC STRUCTURE
1. The capsular polysaccharide antigens:
• 6 serotypes: a - f.
• Encapsulated H. influenzae >>Quellung (capsular swelling) reaction.
2. Somatic antigens:
VIRULENCE FACTORS
• i. Capsule:i. Capsule:
• ii. Outer membrane components:ii. Outer membrane components:
• OMP & LOSOMP & LOS
• iii. Adherence:iii. Adherence:
• iv. IgA proteases:iv. IgA proteases:
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
INVASIVE INFECTIONS
H. Influenzae type b
Respiratory portal of entery (Inhalation)
Colonization of nasopharynx
Penetration of submucosaInvasion of Bloodstream
Meningitis, Epiglottitis, Bacteraemia
Pneumonia, Septic arthritis
Non-Capsulate HI:> Meningitis and Septicaemia > the Neonate
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 ?
LABORATORY DIAGNOSIS
1. Direct examination:– Specimen: CSF, middle ear aspirate,
sputum (purulent).
2. Culture:– Chocolate agar + CO2
– Blood culture bottles– Antigenic detection– Molecular Techniques
Blood agar plate culture of Haemophilus influenzae
Haemophilus influenzae satelliting around Staphylococcus aureus
TREATMENT
• - Systemic illness - Systemic illness – 33rdrd Generation cephalosporins Generation cephalosporins– TMP-SMZ, Ciprofloxacin, ClarithromycinTMP-SMZ, Ciprofloxacin, Clarithromycin
• - Otitis media in children- Otitis media in children• - Pneumonia in adults- Pneumonia in adults• - Acute sinusitis- Acute sinusitis
– Amoxicillin, Augmentin, Clarithromycin, Amoxicillin, Augmentin, Clarithromycin,
PREVENTION• VaccinationVaccination
• Haemophilus influenzae biogroup Haemophilus influenzae biogroup aegyptiusaegyptius ((Haemophilus aegyptiusHaemophilus aegyptius))– Epidemic conjunctivitisEpidemic conjunctivitis– Brazillian purpuric feverBrazillian purpuric fever
• Haemophilus ducreyi> Haemophilus ducreyi> ChancroidChancroid
• Haemophilus parainfluenzaeHaemophilus parainfluenzae