Given a mixture of slender gram-negative rods and coccobacilli after surgery, what is the likely organism if catalase is negative and oxidase is positive?

The organism identified in this scenario is likely Eikenella corrodens due to its distinct microbiological characteristics. In the context of slender gram-negative rods and coccobacilli observed in a mixture, Eikenella corrodens fits the profile well. This organism is a part of the normal flora found in the human oral cavity, and it can be introduced into the bloodstream or tissues during surgical procedures, especially those involving the oral or respiratory tracts.

Key to the identification is the combination of biochemical tests: Eikenella corrodens is catalase negative and oxidase positive. Being catalase negative means it does not produce the enzyme that breaks down hydrogen peroxide, which is a distinctive feature setting it apart from other gram-negative rods. On the other hand, being oxidase positive indicates that it possesses cytochrome c oxidase, an enzyme critical in the electron transport chain.

The result of these biochemical tests helps differentiate Eikenella corrodens from other similar organisms in the gram-negative category that may not share these exact oxidative and catalase characteristics. In this case, Cardiobacterium hominis can also be oxidase positive but typically presents with different morphology and is not slender in shape. Actinobacillus and Proteus