vibrio casei vibrio casei vibrio casei is a gram-negative species of bacterium in the genus vibrio. strains of this species were originally isolated from portions of french soft cheese. genetically similar species and strains have been found in american cheesemaking plants. vibrio casei scientific classification domain: bacteria phylum: pseudomonadota class: gammaproteobacteria order: vibrionales family: vibrionaceae genus: vibrio species: v. casei binomial name vibrio caseibleicher et al. 2009