gardnerella gardnerella gardnerella is a genus of gram-variable-staining facultative anaerobic bacteria. gardnerella microscopic picture of vaginal epithelial clue cells coated with gardnerella vaginalis, magnified 400 times scientific classification domain: bacteria phylum: actinomycetota class: actinomycetia order: bifidobacteriales family: bifidobacteriaceae genus: gardnerellagreenwood and pickett 1980 species gardnerella leopoldii vaneechoutte et al. 2019 gardnerella piotii vaneechoutte et al. 2019 gardnerella swidsinskii vaneechoutte et al. 2019 gardnerella vaginalis (gardner and dukes 1955) greenwood and pickett 1980 eponym it is named after hermann l. gardner (1912–1982), an american bacteriologist who discovered it in 1955.