riemerella riemerella riemerella is a gram-negative, non-spore-forming and non-motile genus of bacteria from the family of weeksellaceae.riemerella is named after o.v. riemer. riemerella scientific classification domain: bacteria phylum: bacteroidota class: flavobacteriia order: flavobacteriales family: weeksellaceae genus: riemerellasegers et al. 1993 species r. anatipestifer r. columbina r. columbipharyngis