pseudomonas excibis pseudomonas excibis pseudomonas excibis is a gram-negative, rod bacterium first isolated from the gastric caeca of the cactus bug (chelinidea vittiger). the type strain is atcc 12293. pseudomonas excibis scientific classification domain: bacteria phylum: pseudomonadota class: gammaproteobacteria order: pseudomonadales family: pseudomonadaceae genus: pseudomonas species: p. excibis binomial name pseudomonas excibissteinhaus