legionella sainthelensi legionella sainthelensi legionella sainthelensi is a gram-negative, catalase- and oxidase-positive, non-spore-forming, motile bacterium from the genus legionella which was isolated from fresh water in regions influenced by the volcanic eruptions of mount st. helens in washington. l. sainthelensi can cause infection in the respiratory tract. genomic informationncbi genome id31584ploidyhaploidgenome size4.10 mbnumber of chromosomes1year of completion2014 legionella sainthelensi scientific classification domain: bacteria phylum: pseudomonadota class: gammaproteobacteria order: legionellales family: legionellaceae genus: legionella species: l. sainthelensi binomial name legionella sainthelensicampbell et al. 1984 type strain atcc 35248, ccug 29672, cip 103885, dsm 19231, msh-4, mt. st. helens 4, nctc 11988