Haemophilus influenzae

General Susceptibility

  • Second & third generation cephalosporins

  • Amoxicillin-clavulanate

  • Fluoroquinolones

  • Clarithromycin/azithromycin

  • Doxycycline

For invasive infections, prefer ceftriaxone as empiric therapy until beta-lactamase production is known - then use ampicillin if beta-lactamase negative.

H. flu beta-lactamase is a whimpy beta-lactamase. If beta-lactamase positive use amox/clav, amp/sulbactam or a second or third generation cephalosporin.

Variable susceptibility to:

  •  Amoxicillin/ampicillin (via beta-lactamase)

  •  TMP-SMX