legionella waltersii legionella waltersii legionella waltersii is a gram-negative catalase- and oxidase-positive bacterium from the genus legionella with a single polar flagellum which was isolated from a drinking water distribution system in adelaide in australia. l. waltersii is named after reginald p. walters. legionella waltersii may can cause pneumonia. legionella waltersii scientific classification domain: bacteria phylum: pseudomonadota class: gammaproteobacteria order: legionellales family: legionellaceae genus: legionella species: l. waltersii binomial name legionella waltersiibenson et al. 1996 type strain 2074-aus-e, atcc 51914, ccug 44924, cip 104965