Haemophilus influenzae
From IDWiki
Background
Microbiology
- Species of Gram-negative bacillus within the genus Haemophilus
- Deficient heme biosynthetic pathway leading to X-factor-dependent growth on media
- Fastidious growth with standard media
- May be encapsulated; non-encapsulated strains are referred to as "nontypeable"
- The group includes Haemophilus influenzae, Haemophilus aegyptius, and Haemophilus haemolyticus
| Test | Biotype | |||||||
|---|---|---|---|---|---|---|---|---|
| I | II | III | IV | V | VI | VII | VIII | |
| Indole | + | + | – | – | + | – | + | + |
| Urease | + | + | + | + | – | – | – | – |
| ODC | + | – | – | + | + | + | – | – |
Clinical Manifestations
- Community-acquired pneumonia, particularly in children, meningitis, bacteremia, mainly type b strains
- Community-acquired pneumonia, acute otitis media, acute sinusitis, acute exacerbation of COPD, mainly untypeable strains
Management
- For beta-lactamase-negative strains, ampicillin is recommended
- For beta-lactamase-positive strains, ceftriaxone or cefepime
- Alternatives include chloramphenicol, ertapenem, meropenem
- Possibly also a fluoroquinolone, azithromycin, clarithromycin, doxycycline, amoxicillin-clavulanic acid
- Duration depends on syndrome being treated:
- Uncomplicated meningitis: 10 days
- Pneumonia: at least 5 days, with clinical improvement
- Septic arthritis: 10 to 14 days
- Pericarditis: 3 to 6 weeks
- Empyema: 3 to 6 weeks
- Osteomyelitis: 3 to 6 weeks
Further Reading
- Antimicrobial Resistance in Haemophilus influenzae. Clin Microbiol Rev. 2007. doi: 10.1128/CMR.00040-06
