cardiobacteriaceae cardiobacteriaceae the cardiobacteriaceae are a family of pseudomonadota, given their own order. they are gram-negative and rod-shaped, with diameters around 0.5 to 1.7 μm and lengths from 1–6 μm. cardiobacteriaceae cardiobacterium hominis on blood agar plate scientific classification domain: bacteria phylum: pseudomonadota class: gammaproteobacteria order: cardiobacteriales family: cardiobacteriaceae genera cardiobacterium dichelobacter rappaport suttonella