pseudomonas costantinii pseudomonas costantinii pseudomonas costantinii is a gram-negative bacterium that causes brown blotch disease in cultivated mushrooms. it demonstrates hemolytic activity. the type strain is cfbp 5705. pseudomonas costantinii scientific classification domain: bacteria phylum: pseudomonadota class: gammaproteobacteria order: pseudomonadales family: pseudomonadaceae genus: pseudomonas species: p. costantinii binomial name pseudomonas costantiniimunsch, et al. 2002