ornithinibacter ornithinibacter ornithinibacter is a genus of gram positive, nonmotile, non-sporeforming bacteria. the bacteria are strictly aerobic and mesophilic. cells of the genus are irregular rods that form branching hyphae. the genus name refers to l-ornithine, the major diagnostic diamino acid in the peptidoglycan. the genus is monospecific, with o. aureus as the only species. ornithinibacter scientific classification domain: bacteria phylum: actinomycetota class: actinomycetia order: micrococcales family: intrasporangiaceae genus: ornithinibacterxiao et al. 2011 species o. aureus