citrobacter rodentium citrobacter rodentium citrobacter rodentium is a gram-negative species of bacteria. it infects the intestinal tracts of rodents, and infrequently is an opportunistic pathogen in humans. citrobacter rodentium scientific classification domain: bacteria phylum: pseudomonadota class: gammaproteobacteria order: enterobacterales family: enterobacteriaceae genus: citrobacter species: c. rodentium binomial name citrobacter rodentiumschauer et al. 1996