listeria welshimeri listeria welshimeri listeria welshimeri is a species of bacteria. it is a gram-positive, facultatively anaerobic, motile, non-spore-forming bacillus. it is non-pathogenic and non-hemolytic. it was isolated from decayed vegetation in the united states by h. j. welshimer, after whom the species is named. the species was first proposed in 1983. listeria welshimeri scientific classification domain: bacteria phylum: bacillota class: bacilli order: bacillales family: listeriaceae genus: listeria species: l. welshimeri binomial name listeria welshimerirocourt et al. 1983