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Moraxella catarrhalis


Gram-Negative Cocci & Coccobacilli   
>Aggregatibacter aphrophilus (formally known as Haemophilus aphrophilus)
>Bordetella pertussis (Causative agent of pertussis or whooping cough. )
>Brucella species:
     1] Brucella abortus
     2] Brucella canis
     3] Brucella melitensis
     4] Brucella suis
>Eikenella corrodens
>Haemophilus species:
     1] Haemophilus influenzae
     2] Haemophilus ducreyi
     3] Haemophilus avium
>Moraxella catarrhalis (formerly known as Branhamella catarrhalis) led
>Neisseria species:  (frequently colonize mucosal surfaces.)
     1] Neisseria gonorrhoeae
     2] Neisseria meningitidis
>Pasteurella multocida

Moraxella catarrhalis:  

  • fastidious, nonmotile, Gram-negative, aerobic, oxidase-positive diplococcus.
  • Can cause infections of the respiratory system (exacerbation of COPD, sinusitis, bronchitis, laryngitis, etc), middle ear (otitis media), eye, central nervous system, and joints of humans.

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Important considerations:  The choice of an agent should be based on local antimicrobial sensitivities, site of infection, cost, and comorbid conditions.   Generally, the most common agents/regimens are listed first.   Listed dosages may need to be adjusted for renal dysfunction.  

  1. Augmentin 875/125 mg orally twice daily or  500/125mg three times daily or 1000mg XR (2 tabs=2000mg) q12h.
  2. Ceftin (cefuroxime oral) 500mg orally twice daily [2nd generation ceph]
  3. Cefprozil (Cefzil®) 500 mg po q12-24h. [2nd generation ceph]
  4. Cefpodoxime (Vantin ®) 200-400 mg orally twice daily   [3rd generation ceph]
  5. Azithromycin 500mg orally x 1 then 250mg  once daily for 4 days
  6. Clarithromycin 500mg po q12h  or Biaxin XL ®: 1000mg (500mg XL x 2) po qd
  7. Bactrim DS orally twice daily
  8. Levofloxacin 500mg – 750 mg IV/PO once daily

Moraxella catarrhalis