The Cardiobacteriales are an order of Pseudomonadota. Like other Proteobacteria, they are Gram-negative and rod-shaped. The order is better known for including the pathogenic HACEK organisms Cardiobacterium hominis and Cardiobacterium valvarum.

Etymology

The Cardiobacteriales take their name from the original type genus Cardiobacterium first described in 1964, when C. hominis was isolated as a pathogenic species from human cases of endocarditis.

The name is formed from Cardiobacterium ("heart bacterium") + -ales ("order (of)").