ilyobacter delafieldii ilyobacter delafieldii ilyobacter delafieldii is a motile, gram-negative, obligately anaerobic rod-shaped bacteria, with type strain 10cr1 (=dsm 5704). it is notable for metabolising beta-hydroxybutyric acid. ilyobacter delafieldii scientific classification domain: bacteria phylum: fusobacteriota class: fusobacteriia order: fusobacteriales family: fusobacteriaceae genus: ilyobacter species: i. delafieldii binomial name ilyobacter delafieldiijanssen and harfoot 1991