Haemophilus

Microbiology

• Gram-negative coccobacilli
• Grow well on chocolate agar
• Form satellite colonies around Staphylococcus aureus

Organisms

• Haemophilus influenzae: causes meningitis and epiglottitis
  • Typeable (a through f)
    • Hib causing most invasive infections and bacteremic pneumonia
    • Hia and Hif also cause severe infections
  • Non-typeable are generally less virulent, but can still cause otitis media, epiglottitis, acute exacerbation of COPD, sinusitis, URTI, and pneumonia
• Haemophilus parainfluenzae, Haemophilus aphrophilus: HACEK group organisms, cause endocarditis
  • Haemophilus paraphrophilus is now Aggregatibacter paraphrophilus
  • Haemophilus aphrophilus is now Aggregatibacter aphrophilus
  • Haemophilus segnis is now Aggregatibacter segnis
• Haemophilus ducreyi: causes chancroid

Management

• About half of all isolates have beta-lactamases