Gardnerella vaginalis

G. vaginalis is a Gram-variable, nonmotile, nonencapsulated rod bacterium. Its taxonomy has changed repeatedly in recent decades. It has thus also been designated as Corynebacterium vaginalis and Haemophilus vaginalis. Based on DNA hybridization, the pathogen is now classified with the regularly shaped, Gram-positive, nonsporing rod bacteria. The natural habitat of this organism is the vagina of sexually mature women. It can also cause vulvovaginitis (va-ginosis). G. vaginalis is found in over 90 % of women showing the symptoms of this infection, usually together with other bacteria including in particular obligate anaerobes (Mobiluncus, Bacteroides, Peptostreptococcus). The organism can be detected in vaginal discharge by means of microscopy and culturing. In the microscopic analysis, so-called clue cells (vaginal epithelia densely covered with Gram-labile rods) provide evidence of the role played by G. vaginalis. This bacterium can be cultured on blood-enriched agar incubated in an atmosphere containing 5% CO₂. The therapeutic agent of choice is metronidazole.