G. vaginalis was earlier known as Corynebacterium vaginalis or Haemophilus vaginalis. Since the bacterium does not requireX and V growth factors, it has been shifted from the genus Haemophilus and has been placed in the genus Gardnerella. Thebacterium is present as a commensal in the male urethra and vagina. G. vaginalis are small, pleomorphic, Gram-negative rods, which are sometimes Gram variable. They are nonsporing, nonmotile, and noncapsulated. G. vaginalis causes nonspecific vaginitis and cervicitis, frequently in association with anaero-bic vaginosis. The condition is characterized by foul-smelling vaginal discharge with a fishy odor and acidic pH.
High vaginal swab or endocervical swab with exudate material is the specimen required for diagnosis of the condi-tion. The specimens are transported in the Stuart medium. Gram staining of the smear shows Gram-variable small bacilli and presence of clue cells. These clue cells are the vaginal epithelial cells covered with many small Gram-variable rods. The bacteria is cultured on a blood agar and incubated anaer-obically at 37°C for 48 hours for colonies. The colonies of G. vaginalis are identified by Gram staining, negative catalasetest, and positive hippurate hydrolysis test.
G. vaginalis is sensitive to penicillin, ampicillin, andtrimethoprim. It is resistant to gentamicin, nalidixic acid, and colistin. Metronidazole is the drug of choice.