undibacterium pigrum undibacterium pigrum undibacterium pigrum is a gram-negative, rod-shaped, oxidase positive, non-spore-forming, and nonmotile bacterium of the genus undibacterium, which was found in drinking water. undibacterium pigrum scientific classification domain: bacteria phylum: pseudomonadota class: betaproteobacteria order: burkholderiales family: oxalobacteraceae genus: undibacterium species: u. pigrum binomial name undibacterium pigrumkämpfer et al. 2007 emend. eder et al. 2011 type strain ccug 49009, cip 109318, cmb nf1b/04, dsm 19792