Eikenella corrodens


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 Led
>Haemophilus species:
     1] Haemophilus influenzae
     2] Haemophilus ducreyi
     3] Haemophilus avium
>Moraxella catarrhalis (formerly known as Branhamella catarrhalis)
>Neisseria species:  (frequently colonize mucosal surfaces.)
     1] Neisseria gonorrhoeae
     2] Neisseria meningitidis
>Pasteurella multocida

Eikenella corrodens

  • Fastidious, Gram-negative facultative anaerobic bacillus.  Oxidase-positive, catalase-negative, urease-negative, and indole-negative, and reduce nitrate to nitrite.
  • Pleomorphic bacillus that sometimes appears coccobacillary and typically creates a depression (or “pit”) in the agar on which it is growing. It grows in aerobic and anaerobic conditions, but requires an atmosphere enhanced by 3-10% carbon dioxide.
  • Colonies are small and greyish, they produce a greenish discoloration of the underlying agar, and smell faintly of bleach (hypochlorite).
  • E. corrodens is a commensal of the human mouth and upper respiratory tract. It is an unusual cause of infection and when it is cultured, it is most usually found mixed with other organisms.
  • Infections most commonly occur in patients with cancers of the head and neck, but it is also common in human bite infections.
  • It is one of the HACEK group of infections which are a cause of culture-negative endocarditis.

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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
  2. Ampicillin-sulbactam (Unasyn) 1.5 – 3.0 grams IV q6h
  3. Ceftriaxone 1-2 grams IV q24h 
  4. Ciprofloxacin 500-750 mg orally q12h or 400mg IV q12h (Severe/complicated: 400mg IV q8h)
  5. Levofloxacin 500mg – 750 mg IV/PO once daily

Eikenella corrodens