Haemophilus species of clinical importance

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Haemophilus species of clinical importance

• H. influenzae
• H. parainfluenzae
• H. ducreyi
• H. influenzae aegyptius

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Haemophilus influenzaeage dependence
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Haemophilus influenzaeseasonal variation
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Decline in Haemophilus influenzae infections
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Haemophilus affected organs
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Haemophilus a Gram negative bacillus

• A Gram negative bacillus

• Grows of chocolate agar with factors X (hemin)
  V (NAD)

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H. influenzae-bsymptoms

• Runny nose, low grade fever, headache
• Septicemia septic arthritis, conjunctivitis,
  cellulitis, epiglotitis, meningitis, convulsions,
  coma
• Airway obstruction suffocation

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H. influenzae-bsecondary complications

• Loss of hearing and learning disabilities (mental
  retardation)

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H. influenzaenon-b strains

• Second commonest cause of otitis media among
  young children
• Pneumonia in adults

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H. influenzae-bvirulence factors

• Capsule is the major pathogenesis factor it is
  antiphagocytic
• LPS causes the usual inflammatory and
  cardio-vascular symptoms
• IgA1 protease may aid mucosal colonization

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H. influenzae-bdiagnosis

• History and physical examination
• Blood culture (positive in 50)
• PRP (polyribitol phosphate in serum and urine
• Gram-negative coco-bacilli in CSF (in 80 of
  meningitis cases)

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H. influenzae-btreatment

• Cephalosporin is the antibiotic of choice

Early and prompt treatment is essential. Delays
often lead to meningitis, epigloititis and death.
If the patient does survives, often there is a
loss of hearing and mental and retardation.
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Haemophilus ducreyi

• causative agent of chancroid

• 5,000 cases per year in the US
• Endemic in areas of Africa and Asia
• Commonest cause genital ulcer in sub-Saharan
  Africa

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Haemophilus ducreyi

• Gram negative bacillus

• Grows of chocolate agar with factors X (hemin)
  but not factor V (NAD)

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Haemophilus influenzae aegyptius

• An opportunistic infection
• can cause conjunctivitis, fever and vomiting
  (Brazilian purpuric fever) in children
• Grows under the same conditions as H. influenzae