listeriaceae listeriaceae the listeriaceae are a family of gram-positive bacteria. the cells are short rods and can form filaments. they are aerobic or facultative anaerobic. spores are not formed. some species can cause human and animal listeriosis. listeriaceae listeria monocytogenes scientific classification domain: bacteria phylum: bacillota class: bacilli order: bacillales family: listeriaceaegarrity et al. 2001 genera brochothrix listeria