Gardnerella

The genus Gardnerella, consisting of a single facultatively anaerobic Gram-variable rod species, Gardnerella vaginalis, is classified under the family Bifidobacteriaceae, suborder Actinomycineae, phylum Actinobacteria. Although the bacterium possesses a thin gram-positive cell wall, it may appear either gram-positive or gram-negative under the microscope. The clinical significance of G. Vaginalis, as well as its taxonomic position, has long been a matter of dispute largely due to variable Gram staining and lack of appropriate detection and identification methods (reviewed in Catlin1). Thus far, more than 1000 papers were addressed to this small (0.4 by 1.0–1.5 μm), pleomorphic, rod-shaped, fastidious bacterium organism. Almost a century ago, Curtis et al.2 reported that Gramstained purulent vaginal discharges contained mainly gramnegative bacilli that he and his colleagues were unable to cultivate. It was not until 1953 that Leopold3 succeeded in isolating such bacteria from men with prostatitis and women with cervicitis. The organism was named Haemophilus vaginalis by Gardner and Dukes in 19554 because it was a gram-negative, rod-shaped bacterium that could be isolated on blood agar and it was believed to be responsible for a characteristic vaginal discharge.