undibacterium parvum undibacterium parvum undibacterium parvum is a gram-negative, rod-shaped, oxidase positive, non-spore-forming, and low nutrient-loving bacterium of the genus undibacterium and family oxalobacteraceae which was found in drinking water. undibacterium parvum scientific classification domain: bacteria phylum: pseudomonadota class: betaproteobacteria order: burkholderiales family: oxalobacteraceae genus: undibacterium species: u. parvum binomial name undibacterium parvumeder et al. 2011, sp. nov. type strain ccug 49012, cip 109317, cmb nf2a/04, dsm 23061