Eikenella - Catalase & Oxidase

This version of the course is no longer available.
The page below is a sample from the LabCE course Case Studies in Clinical Microbiology. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about Case Studies in Clinical Microbiology (online CE course)
Eikenella - Catalase & Oxidase

  • Eikenella corrodens (E) belongs to the HACEK group of miscellaneous gram-negative bacilli which includes Haemophilus aphrophilus (H), Actinobacillus actinomycetemcometans (A), Cardiobacterium hominis (C) and Kingella kingae (K).
  • Cytochrome oxidase and catalase are two rapid tests that help separate the several members of this group.
  • Eikenella corrodens shows cytochrome oxidase activity, but not catalase activity.
  • The positive oxidase reaction separates E. corrodens from Haemophilus aphrophilus and Actinobacillus actinomycetemcomitans, which are both negative.
  • A. actinomycetemcomitans is also catalase positive, an additional characteristic separating it from E. corrodens, which is negative.
  • As Kingella kingae is also oxidase positive and catalase negative, other tests are needed for differentiation. K. kingae produces acid from glucose and maltose (E. corrodens is asaccharolytic).